In this paper the optical properties of some organic and inorganic optical storage thin films have been studied. The organic thin films include cyanine, phthalocyanine and azo- dye, which were prepared by spin-coating or LB methods. The inorganic thin films were GeSbTe phase-change materials, which were synthesized by sputtering method. The complex refractive indices were measured by spectroscopic ellipsometry technique. The optical properties are analyzed by using of different dispersion models that are based on Kramers-Kronig transformation. Finally, the application in optical storage with these thin films are discussed and demonstrated.

Secondary-ion mass spectrometry and secondary-neutral mass spectrometry use the atoms and molecules sputtered from the surface of a solid by energetic-ion impact to derive information on the elemental composition at the surface and, in conjunction with continuous sample erosion, in thin films. This contribution summarizes the basic principles of these techniques. Selected examples for the characterization of thin films and surfaces from various technologically important areas are presented, emphasizing aspects of quantification, detection sensitivity, and spatially resolved analyses. Specifically, reliable quantification schemes utilizing either post-ionized neutral species or specific molecular ions are highlighted; furthermore, it is shown that these mass spectrometric techniques enable the sensitive detection of essentially all elements at very low concentration levels, reaching even into the sub-parts-per- billion range in favorable cases. Finally, aspects of spatially resolved analyses are discussed, covering depth profiling, surface imaging and a fully 3D characterization of solids. It is exemplified that by using suitable primary- ion bombardment conditions, a lateral resolution of less than 100 nm and an in-depth resolution of a few nm can be achieved in thin-film analyses.

We report a unique technique to measure the refractive index (n), extinction coefficient (k), and thickness of thin films based on either the reflection or transmission spectra. The method combines a spectrometer, an optical microscope and a video camera. It is inexpensive, versatile and fast (< a few sec). Using this technology, n&k of 1.68 and 0.376, respectively, at 1500 nm was measured on a planar photonic crystal. The photonic crystal with a dimension of 117 X 90 micrometers ² mm has a periodic cermet structure on Si substrate made by Deutsch Telekom using the electron induced deposition.

The challenge of meeting the ever increasing demands for low-cost information storage media with greater information storage density and rapid access has prompted development of sophisticated optical technologies, e.g. CD (Compact Disc) and DVD (Digital Video Disc) in Read Only (ROM), Recordable (R), Re-writable (RW) and Random Access Memory (RAM). Here the suitability of Time of Flight-Energy Elastic Recoil Detection Analysis (ToF-E ERDA) to characterize optical storage media has been investigated. High-energy heavy ions (48 MeV ⁸¹Br⁸⁺ and 60 MeV ¹²⁷I¹⁰⁺) from an accelerator were used to analyze CD-ROM, CD-R and CD-RW structures. Simultaneous characterization of H, C, O, Al, P, Co, Cr, Ge, Sb/Te could be made. The results demonstrate the unique power of the technique for characterizing the structure and depth profile of the optical multi-layers as well as the ingress and influence of foreign species.

The fractal growth of 2D thin films on metal surface is studied by means of kinetic Monte Carlo simulation, using realistic growth model and physical parameters. Emphasis is given to time dependence of the size S(t) and branch width b(t) of the island. It is found that the island size S(t) grows with time t as t^k, where growth-exponent k is slightly less than one when averaged from all islands. Similar results for the branch width of islands are also obtained from the simulations are not very low coverage, i.e., b(t) (infinity) t^(alpha ). The kinetic scaling values k and (alpha) of fractal growth of thin films may be helpful to understand the growth mechanism of thin films.

By means of an optical investigation involving the envelope function approximation using the full 8 X 8 Kane Hamiltonian, it has been demonstrated that the valence band is primarily responsible for the separation between the H1- E1 and L1-E1 intersubband transition energies of semiconducting HgTe/Hg_1-xCd_xTe superlattices with a normal band structure. This results in an unequivocal determination of the valence band offset between HgTe and CdTe, (Lambda) , which is 570 +/- 60 meV at 5 K for both the (001) and the (112)B orientations. In order to correctly predict the temperature dependence of both intersubband transition energies, the following is required: (Lambda) is also temperature dependent according to d(Lambda) /dT equals -0.40 +/- 0.04 meV/K; the heavy hole effective mass has a significant temperature dependence; and the energy gap E_g(HgTe, 300 K)equals -160 +/- meV which is appreciably lower than the extrapolated values found in the literature.

We use exciton signatures in optical absorption spectra to probe material and structural properties of InSb/Al_xIn_1-xSb multiple quantum wells. Excitonic transition lines have been observed up to room temperature for the system in which exciton binding energy is only 1 meV largely due to very weak LO-phonon-electron coupling. Parabolically graded quantum wells were grown and used to study the band offset ratio at the InSb/Al_xIn_1-xSb heterointerface. A 0.62 +/- 0.04 offset ratio is extracted from the exciton transitions measured on samples with Al concentrations in the range 2% to 12%. Furthermore, deformation potentials in the system have been studied. The hydrostatic and the shear deformation potentials are determined simultaneously to be around -6.5 +/- 0.3 and -1.5 +/- 0.2, respectively.

The principle, capabilities, advantages and limitations of the optically detected magnetic resonance (ODMR) technique will be briefly described. The ability of the ODMR technique to provide important information on physical properties of semiconductor thin films and layered structures will be highlighted. These include chemical identification, electronic and geometric structures of defects, carrier recombinations, etc. The important role in providing valuable feedback for improvement of growth process and in engineering material properties for device applications will be demonstrated. Representative cases from Si/SiGe- and InP- based structures grown by molecular beam epitaxy will be discussed as examples. The most recent progress, on-going efforts and prospects in achieving unprecedently high spectral, time and spatial resolution of the ODMR technique, meeting the demands and challenges raised by the increasing miniaturization of future electronic and optoelectronic devices, will also be outlined.

The invention and the investigation of the semiconductor quantum well structures have influenced and changed the condensed matter physics, microelectronics, opto-electronics as well as other related scientific and technological fields tremendously in last three decades. The quantum well, superlattice and their new development or new generation, that is quantum wires and quantum dots and many other microstructures provide us furthermore really new challenge for the infrared application and technology. The cascade infrared laser, the multi-color and tunable infrared detectors, as well as the focus plane array based on the intersubband or interband transitions in usual multi quantum well or type-II superlattice structures are some of the examples. We report here mainly a comprehensive investigation on the application of GaAs/AlGaAs multi- quantum well structures as the long wavelength infrared detectors and their focus plane arrays based on the intersubband transitions of the quantum wells. The fundamental parameters of the devices, the performance of the detectors and the arrays, the modulation and tuning of detection wavelength via atom intermixing between wells and barriers, the coupling of the radiation with the electronic transitions and the demonstration of the imaging will be reviewed and discussed together with the comparison to the traditional infrared detectors.

The spontaneous and stimulated emission in ZnCdSe/ZnSe asymmetric double quantum wells have been studied. The exciton photoluminescence both in the narrow well and in the wide well is influenced by two factors, the exciton tunneling and the thermal dissociation processes. The change of the emission intensity is determined by the stronger one. The carrier tunneling through the thin barrier is conductive to the stimulated emission from the wide well, and the threshold can be lowered by optimizing the structure.

Low-dimensional diluted magnetic semiconductors have been made by epitaxy and microfabrication techniques. Multiple quantum wells of the Cd_1-xMn_xTe/ZnTe (x equals 0.1) system were grown by molecular beam epitaxy. Quantum wires of Cd_1-xMn_xSe (x equals 0.08) were fabricated from the quantum well of Cd_1-xMn_xSe/ZnSe by the electron beam lithography. Quantum dots of Cd_1-xMn_xSe (x equals 0.03) were grown by the self-organization mode on a ZnSe layer. Magneto-optical properties of these low dimensional structures were studied by time-resolved photoluminescence. The transient photoluminescence in the Cd_1-xMn_xTe/ZnTe multiple quantum wells shows the formation processes of magnetic polarons of excitons. The exciton luminescence from the quantum wires of Cd_1-xMn_xSe displays the influence of the 1D quantum confinement effect for the exciton states with the effective g-value of 100 - 150. The exciton luminescence from the wires is linearly polarized parallel to the wire direction. The exciton luminescence in the quantum dots shows the strong confinement effect of the exciton energy corresponding to the dot size of 4 - 6 nm as well as large effective g-value of 89. The quantum dot excitons also exhibit marked increase of the luminescence lifetime with increasing the magnetic field, which is caused by suppression of the non-radiative process due to the shrinkage of the exciton wavefunction.

GaN films were grown on (111)GaAs substrates by radio frequency magnetron sputtering in an ambient of argon and nitrogen, using gallium target. The structural properties of the GaN films were investigated by conventional (theta) - 2(theta) x-ray diffraction, high-resolution (omega) rocking curve and rotary phi scan. Crystalline wurtzite GaN films were obtained on (111)GaAs at substrate temperatures between 600 and 700 degree(s)C. The crystal quality of the GaN films was examined as a function of nitrogen content in sputtering gas and the best value of full width at half-maximum of rocking curve for the (0002)GaN was obtained at 880% nitrogen content in the investigated regions.

The effect of oxygen incorporation on electrical and optical properties of Be- and Si-doped InP grown by solid source molecular beam epitaxy has been studied. Oxygen was observed to reduce both the Be and Si doping efficiencies in InP and to introduce recombination centers that degrade the photoluminescence property. The compensation in Be-InP was more pronounced than in Si-InP. With high oxygen impurity concentration, Be-InP was found to be n-type in Hall measurements. Electrical inactivity of Be is likely due to the formation of Be-O complexes in InP. Oxygen was originated from the phosphorous source and could be reduced by employing lowered phosphorous cracker temperature.

We present a new approach to determine the thickness and composition of individual layers in molecular beam epitaxy (MBE) grown multiple quantum well (MQW) structures by double crystal X-ray diffraction. The mean perpendicular lattice constant (d^{(perpendicular})_SL0) and the period (P) of the MQW structures are calculated from the zeroth satellite peak position and the satellite peak spacings respectively. The thickness and composition of the individual layers are found by combining the growth times of the individual layers with d^{(perpendicular})_SL0 and P. MQW structures of the form GaAs/XGaAs (X equals group III elements) grown on GaAs substrates are used to derive the theory for this approach and two MQW samples in the GaAs/In_xGa_1-xAs system are studied as an example of this approach. The results for both samples are checked by dynamical simulation. The simulated x-ray rocking curves for both samples have excellent agreement with the corresponding experimental x-ray rocking curves. This approach may be applied to other MQWs structures with two layers where one is a binary and the other is a ternary which includes the binary, such as AlAs/Al_xGa_1-xAs. It is therefore a technique not only for characterizing device structures containing MQW's but also for calibrating group III fluxes in MBE systems.

The development of high quality semiconductor thin films for different applications is a demanding problem in material science. InN has not been an intensively studied as AlN and GaN. There is relatively little information on the fundamental optical properties, charge carrier transport, and the properties and behavior of electrically active defects in the material. The absence of good-quality material lead even to conflicting data reported in the literature concerning the optical gap and band structure. In this publication it will be shown that InN thin films can be successfully grown using the MO MBE method. For the first time the proper choice of growth conditions allows to obtain good quality InN thin films with a charge carrier concentration as low as 8.8 X 10¹⁸ cm^-3.

p-type poly-Si thin films were prepared by aluminum induced crystallization (AlC) and doping of a-Si:H. The a-Si:H precursors were deposited by plasma enhanced chemical vapor deposition on glass substrates and then covered with thin Al layers of different thickness. The crystallization was performed by conventional thermal annealing. X-ray diffraction and secondary ion mass spectroscopy measurements were carried out to study the structure change and the Al profile in the annealed films. Resistivity, Hall mobility and carrier concentration were also measured. Results showed that poly-Si films could be obtained by annealing a-Si:H in contact with a thin Al layer at 450 - 550 degree(s)C for 5 - 60 minutes. The crystallized films are p-type and have low resistivity, high Hall mobility and carrier concentration of 0.06 (Omega) cm, 20 cm²/Vs and approximately 10¹⁸ cm^-3, respectively, largely improved compared with the reported results.

Polycrystalline thin films of CuInSe₂ were electrodeposited on to titanium substrates from acidic baths. For polysulphide electrolyte containing NaOH, Na₂S and S (each 1 m) these films show best photoresponse, when electrodeposited with 60 m mole sodium citrate concentration. Due to surface treatment these films show good photoelectrochemical behavior with high conversion efficiencies and stability. Chemical etching is found to improve short circuit current and fill factor, whereas photoelectrochemical etching technique improves the stability of photo-anode in polysulphide solution. The efficiency is 4.04% and 3.5 and fill factor is 0.57 and 0.49 for chemically etched and unetched CuInSe₂ thin films, respectively.

High power InGaAsP/GaAs separate confinement heterostructure single quantum well lasers have been grown by liquid phase epitaxy (LPE). The maximum output power as high as 4 W has been obtained with the threshold current density 300 A/cm² and the external differential quantum efficiency 80%. Measurements and theoretical analysis showed that the wafers grown by LPE are in good agreement with design and can be comparable to that grown by MBE and MOCVD.

The surface morphologies of both MBE and LPE HgCdTe films were observed by optical microscope and atom force microscope. Both HgCdTe films were grown on CdZnTe substrates. It was found that the surface morphology of LPE film is very sensitive to the orientation of CdZnTe substrate, while MBE film surface morphology is mainly dependent on the surface morphology of the substrate. The characteristic of the surface morphologies and the non- flatness of HgCdTe LPE and MBE films in different scales are studied.

As a coating material with excellent durability in 8 - 12 micrometers waveband, GaP films can be used as anti-reflective and protective layers on the windows and domes of ZnS, ZnSe and Ge. In this paper GaP films have been deposited by radio frequency magnetron sputtering of single crystalline gallium phosphide. The deposition rate, composition, structure, hardness and optical properties of GaP films have been investigated, and it's application used as anti-reflective and protective films on ZnS substrate has also been studied.

Grazing incidence x-ray diffraction measurements at different grazing angles for self-organized Ge dots grown on Si(001) are carried out by using synchrotron radiation as a light source. Deformation strains in the substrate underneath or surrounding the dots induced by formation of Ge quantum dots are investigated. Besides a tensile strain existing underneath the dots, a peak located at the higher angle side of Si(220) or Si(400) is observed for the first time, the origin of this peak is attributed to the near surface compressive strain in the peripheral substrate regions surrounding the Ge dots. This compressive strain corresponds to a -0.8% lattice constant change parallel to the interface.

Reflection high energy electron diffusion (RHEED) is used to study the Si growth on a Si(111)(root)3X(root)3-B surface, prepared by various procedures. The analysis of RHEED patterns, specular beam intensity oscillations and dependencies of specular beam intensity on incidence angle (rocking curves), shows that the Si growth mode and epilayers quality depend on both an initial boron coverage and the way of (root)3X(root)3-B surface phase formation. Increase of transition temperature, at which Si growth mode converts from layer-by-layer to step-flow growth mode, is discussed in terms of the theory of surfactant-mediated growth on semiconductor surfaces.

In this paper, the surface area of solar cell is determined by the capacitance measurements of MOS structure. The texture etching technology can be controlled according to the change of silicon surface area, furthermore, the textured silicon surface and interface characteristic of solar cell can be studied by measuring the relationship of capacitance and voltage for MOS structure.

Atomic force microscopy (AFM) was used to investigate the surface topography of GaN grown by radio frequency plasma assisted molecule beam epitaxy and etched with a 1.0 M KOH solution in a photoenhanced process. Whiskers were observed in AFM photo and correlated with dislocations. Dislocations density was evaluated from whiskers density, and confirmed by x-ray 2D triple axis mapping estimated results.

Threading dislocations with edge components were investigated by a high-resolution transmission electron microscopy in undoped GaN epilayers grown on Al₂O₃ substrates. Two types of core images were observed. One is a fully filled core with regular contraction and expansion of diffraction bright dots and the other is incompletely filled with one bright dot less and irregular contraction and expansion of bright dots. The impurities around the cores were detected to contain oxygen and carbon elements by energy-dispersive x-ray spectrometer. This suggests that both types of dislocations be decorated with impurities.

A novel concept to develop far-infrared (FIR) Si detectors is proposed based on homojunction internal photoemission. As the first approach, a 48 micrometers (lambda) _c Si FIR detector is demonstrated on molecular beam epitaxy grown homojunction multilayers consisting of highly doped emitter layers and undoped intrinsic layers. The detector shows high responsivity over a wide wavelength range with a peak responsivity of 12.3 +/- 0.1 A/W at 27.5 micrometers and detectivity D* of 6.6 X 10¹⁰ cmHz^1/2/W at 4.2 K. The (lambda) _c and bias dependent quantum efficiency agree well with theory. Based on the experimental results and the model, Si FIR detectors (40 approximately 200 micrometers ) with high performance and tailorable (lambda) _c can be realized using higher emitter layer doping concentrations.

In this paper, through the analysis and in consideration of the facts which influence on the ultimate output power of semiconductor laser, we have designed a laser structure with gradient refraction index separate confinement single quantum well (GRIN-SCH-SQW) and have grown the laser structure by MBE. Moreover we have also fabricated array lasers by broad area structure. The lasers are cleaved into cm bars and coated with high- and low-reflectivity films (approx. 95% and 5%). The QCW output power of the array laser has reached 60 W (100 microsecond(s) , 500 Hz), the peak wavelength of the device is 806 approximately 810 nm.

Co-diffusion processing is emerging as a promising simplified process for manufacture of terrestrial back surface field (BSF) solar cells. In this work, we present results about co-diffusion of two dopant elements (phosphorus and boron) in a single thermal cycle in order to form emitter and BSF thin layer simultaneously. According to the measured sheet resistance, it was found that uniform, stable and controllable diffusion layers on front and back surface of silicon wafer can be obtained with co-diffusion method. Using the co-diffusion method, some silicon BSF solar cells with an efficient of more than 12% (at AM1) were prepared. The measurement results of minority carrier lifetime show that boron diffusion in back side of silicon wafer has a gettering effect on the p-n junction area and can improve the characteristics of solar cells.

The electroluminescence is reported from ZnS doped with terbium (Tb) thin films prepared by radio frequency magnetron sputtering method. We have systematically investigated the characteristics of the ZnS:TbF₃ thin film electroluminescence devices, such as film characteristics of the ZnS/Tb active layer, substrate temperatures during magnetron sputtering and Tb concentration of the active layer, etc. From the results obtained, the mechanism of electroluminescence of thin film EL devices is discussed, and then the relationships between the EL characteristics and the device parameters are considered.

The tunable ridge waveguide distributed Bragg reflector (DBR) lasers designed for wavelength-division-multiplex (WDM) communication systems at 1.55 micrometers by using selective area growth is reported. The threshold current of the DBR laser is 62 mA and the output power is more than 8 mW. The isolation resistance between the active region and the Bragg region is 30 K(Omega) . The total tuning range is 6.5 nm and this DBR laser can provide 6 continuous standard WDM channels with 100 GHz channel spacing; in the tuning range, the single mode suppression ratio is maintained more than 32 dB and the maximum output power variation is less than 3 dB.

Employing photoelastic effect with thermally stable and controllable metal stressor stripes for low propagation loss (on the order of 1 dB/cm) optical waveguide has been achieved in both InP and GaAs based planar waveguides. The study of stressors is based on Ni and WNi stripes. Planar processes, involving both photoelastic WNi stressor and He- implantation, have been used in the fabrication of single- quantum-well photoelastic GaAs/AlGaAs lasers and of the InGaAsP/InP Franz-Keldysh effect electroabsorption waveguide modulators. Get high performance photoelastic semiconductor laser and electroabsorption modulator.

Due to the mature material growth and device fabrication technology, GaAs/Al_xGa_1-xAs quantum-well infrared photodetector (QWIP) has been extensively studied and used in remote sensing, particularly in long wavelength range, e.g. the atmospheric window region of 8 approximately 14 micrometers . This paper reports the using of intermixing techniques to modify GaAs/AlGaAs multiple quantum well photodetectors (QWIPs). A red shift in response wavelength of QWIP has been obtained both by rapid thermal annealing (RTA) and proton implantation. The peak response wavelengths has been shifted into the atmospheric window (8.3 micrometers ) from the originally 7.7 micrometers . The response spectra have been measured as the function of the different temperature of the RTA and the ion doses in the range from 4 X 10¹⁴ to 5 X 10¹⁵ cm^-3, respectively. The device performance such as dark current and blackbody response are also measured at different conditions. The effect of RTA and ion implantation on the device performance has been interpreted theoretically by the interdiffusion of Al atoms across the GaAs/Al_xGa_1-xAs heterointerfaces.

Reflection Fourier transform infrared (RFTIR) measurements were performed on backside-illuminated InSb infrared focal plane arrays for thinning process monitoring. InSb detector film thickness and its variation across the film can be measured from the RFTIR spectra taken by this contactless and non-destructive technique.

Results of our recent experiments relating to the synchrotron-radiation (SR)-excited growth of ZnTe on the (100) ZnTe substrate using metalorganic sources are described. We have clarified the growth characteristics and quality of ZnTe films. The shape of deposited film suggests that surface excitation process, i.e., the excitation of the adsorbed species or sample surface, will be the dominant mechanism. The quantum yield for forming ZnTe molecules was estimated to be as high as 0.3% in the room temperature growth. ZnTe epitaxial film without carbon and oxygen contamination is attainable even at room temperature using SR as a light source. Near band gap luminescence can be observed even in the films grown at room temperature. It seems that a use of N₂ carrier gas is promising for the inclusion of nitrogen as shallow acceptors and the suppression of defects. Through these experiments, we propose that the SR-excited growth is a powerful technique for a novel low temperature growth of compounds.

Strain dependence of the band structure of (beta) -FeSi₂ has been investigated using first principles calculations based on the density functional theory. Indirect transition in the band structure is predicted, when the crystal is strain-free. On the other hand, the band structure changes to the direct transition, when the a-axis is expanded or c- axis is compressed. In (beta) -FeSi₂ pseudomorphic layer grown on Si(100) substrate, the direct band structure is expected.

In this work, we present a new approach to determining Poisson's ratio of AlAs. This approach requires the growth of a particular structure with a multiple quantum well (MQW) - 10X[500 angstroms GaAs/800 angstroms Al_xGa_1-xAs] followed by two single layers - 0.5 (mu) AlAs and 0.5 (mu) Al_xGa_1-xAs on a GaAs substrate. The x-ray rocking curves of the as-grown sample give the perpendicular lattice constants in the two single epilayers, and following chemical etching to remove the two single layers, x-ray diffraction measurement of the MQW is used to determine the Al fraction x. With this data, we obtain a value for Poisson's ratio of AlAs which is V_AlAs equals 0.255 +/- 0.003 assuming Vegard's law and a linear variation of the Al_xGa_1-xAs lattice constant with x. However we obtain V_AlAs equals 0.328 +/- 0.003 if, as proposed by Z. R. Wasilewski, a nonlinear relationship with the bowing parameter c equals 1.245 X 10^-3 is assumed. The value of 0.328 is in good agreement with most recent results obtained which do not assume Vegard's law. Our results therefore support the violation of Vegard's law in describing the relationship between the lattice constant of AlGaAs and its composition.

Films of a-SiO_x with different oxygen content were deposited by electron cyclotron resonance microwave plasma technique at room temperature, where the films were annealed in an Ar ambient for 30 minutes at temperatures range from 250 to 1050 degree(s)C. The system of nc-Si quantum dots dispersed in SiO₂ matrix was obtained for the films annealed at 1050 degree(s)C. The structural change induced from annealing was characterized by infrared and Raman spectra, which was correlated with the identification of luminescence centers. A broad photoluminescence band centered at 750 and 770 nm is attributed to the quantum confinement effect of the Si clusters. Another PL band between 560 - 620 nm is attributed to the defects in the interfacial regions: self- trapped excitons.

In this paper, we have fabricated a 20 period CdSe/ZnSe MQW's on (001) orientated GaAs grown by metalorganic chemical vapor deposition under se-rich condition at the growth temperature of 500 degree(s)C. CdSe/ZnSe MQW's structure was characterized by means of x-ray diffraction and Raman scattering. These experimental results indicated the formation of new Cd_1-xZn_xSe layers and the existence of Cd and Zn vacancies in CdSe/ZnSe MQW's. The photoluminescence spectra of CdSe/ZnSe MQW's at low temperature was composed of a very strong and narrow band A at 2.4 eV and a weak and broadened band B at 2 eV. In order to understand the influence of Cd diffusion on the structure and photoluminescence (PL) of CdSe/ZnSe multiple quantum wells (MQW's), a new model of Cd diffusion in CdSe/ZnSe MQW's was given. Based on the simulation of Cd diffusion in CdSe/ZnSe MQW's and the calculation of the envelop-function approximation, the origin of PL of CdSe/ZnSe MQW's was discussed.

The Fourier transform and double modulation Fourier transform photoluminescence measurements were performed on HgCdTe films from liquid helium temperature to room temperature in the infrared band to 10 micrometers where the influence from room temperature background blackbody emission is very strong. From the band to band transition photoluminescence peak, which dominated in HgCdTe films with the small cadmium composition, the cadmium composition, crystal-quality-related band tail energy, and the active energy of the non-radiative Shockly-Read center, are obtained. The photoluminescence characterization method is also used to investigate the intentionally doped impurity behavior in HgCdTe. The amphoteric impurity behavior of As implanted in HgCdTe is discovered with the donor and acceptor energy level of 8.5 meV and 31.5 meV, respectively. The Ag impurity level of 70 meV in MBE HgCdTe is also found.

This paper presents the carrier distribution of MIS/IL solar cell in the strong inversion condition. The variation of the surface potential Vs with the fixed positive charge density Q_s/q, energy structure and the sheet resistance have been calculated using Fermi statistics distribution. Based that, the MIS/IL solar cells are fabricated with the solar grade silicon material. Consequently, the difference of the solar cell performance before and after doping cesium is compared.

CdTe thin films are obtained by on glass substrates by vacuum vapor deposition. This work mainly presents the optical and electrical characteristics of the CdTe films by varying stoichiometry of Cd and Te, doping-In and thermal treatment with N₂. The variation of band gap and absorption coefficient is studied as well as the resistivity. The results show that the undoped-In samples have very high resistivity on which thermal treatment has little effect, which proves that the undoped CdTe thin film is high resistivity semiconductor. On the other hand, the resistivity of the doped-In samples decreases after thermal treatment. In general, the optical and electrical characteristics of the prepared CdTe thin film can be improved by proper doping and thermal treatment.

The micro-photoluminescence ((mu) -PL) scanning has been performed on a GaAs/AlGaAs single V-grooved quantum wire (QWR) along the direction perpendicular to the wire. The variation of (mu) -PL spectra in different spatial positions with different quantum structures have been observed. In the region of QWR the PL spectra contain the peaks from QWR, necking quantum well and vertical quantum well while in that of about 1 micrometers leaving away from the QWR the PL spectra show only the peaks from side-wall quantum well and top quantum well. All the acquired spectra have been fitted by Gaussian line shape and the different PL components are decomposed. The intensity variation with the spatial position directly demonstrates the origin of the PL correlated to the different quantum structures. The PL energy for the each quantum structures has been precisely determined.

The semiconductor solid phase epitaxial model of continuous laser-annealing is used to simulate the laser-annealing process of different doping concentration of InP at the continuous Nd:YAG laser. Specially, quasi-static model is used to simulate the radial heat dissipation from radiant region to radiationless region. At the same time, thermal conductivity and optical absorption coefficient varied with temperature is also considered. The method of hidden-form different is used in solving 1D, non-homogeneous, nonlinear partial differential equation of heat conduction. At the room temperature T₀ equals 300 K and the power intensity of laser I₀ equals 800 W/cm², the result is that the temperature of surface reaches about 1290 K after 3.8 sec.

ZnSe/Zn_1-xMn_xSe quantum wires were fabricated on mesa-patterned GaAs substrate. The light hole-heavy hole excitonic level crossing, which occurs at certain magnetic field B_c, is observed in the time-resolved magneto- photoluminescence measurements carried out on the samples. The shift of B_c for the quantum wire samples is well interpreted by taking into account of both the strain effect and the 1D quantum confinement effect.

We have studied the characteristics of reactive ion etching of indium nitride, using CH₄ and H₂ gases. The effects of CH₄/H₂ gas composition and total gas pressure on the etching rates were investigated. It was found that variation of CH₄ concentration in gas mixtures leads to changes in both the etching rate and the surface morphology. Smooth etched InN surface with the rate of around 610 approximately 710 angstroms/min was obtained in the range of 5 approximately 15% CH₄ concentration and 25 approximately 55 Pa pressure.

CdTe film can be prepared on the glass by vacuum vapor deposition. We change the stoichiometry of Cd:Te, dope In, and thermally treat the samples in N₂. Then, the compositions, structure, and grain size are studied by XRD, SEM and AES. The results reveal that the surface morphology and microstructures of the samples are improved after thermal treatment, In is incorporated into CdTe, and forms CdTe:In. Moreover, the preferential growth orientation along <111> appears.

Indium phosphide/silica composite thin films have been fabricated on water-cooled substrates and heated substrates respectively by radio frequency magnetron cosputtering technique. X ray diffraction patterns and optical absorption and photoluminescence spectra at room temperature strongly suggest that InP nanocrystals exist in the SiO₂ matrices of the films deposited on water-cooled substrates after annealing and of the films deposited on heated substrates. X-ray photoelectron spectra show that there are quite a log of oxides of In and P and quite many oxygen deficiencies of SiO₂ in the films deposited on water-cooled substrates, but there are few deficiencies of SiO₂ and much less oxides of In and P in the films deposited on heated substrates. The component of InP increases and the oxides of In and P and oxygen deficiencies in SiO₂ diminish at a large extent under suitable annealing temperature and time in a high vacuum system, but the role of annealing is limited because of the escape of P. The problem can be solved quite well by coating a SiO₂ layer on the surfaces of the films before annealing and then annealing the films in H₂ of 10³ Pa.

CuInSe₂(CIS) films directly electrodeposited on sputtered Mo-glass, sprayed SnO₂-glass substrates had been accomplished at room temperature in the potentiostatic mode from a bath containing CuCl, InCl₃(DOT)4H₂O and SeO₂. The acidity of bath was adjusted to 1PH. Energy dispersive spectrometry, atomic force microscopy (AFM), x- ray diffraction and hot-probe method was utilized to characterize the CIS films. The key factor for preparing single-phase CuInSe₂ is the proportion of CuCl, InCl₃(DOT)4H₂O and SeO₂. The CIS films are nearly stoichiometry of CuInSe₂ and polycrystalline on Mo- glass. The Cu excess films are p-type semiconductor, and the In excess films n-type. The deposition potential obviously affects the surface morphology of CIS films. AFM results had indicated that the CIS films on Mo-glass grow in layer and on SnO₂ glass in island.

Carbon-rich SiC thin films were synthesized by rf-reactive sputtering at different anodic voltages, 1.2 kV, 1.6 kV and 2.0 kV respectively. XPS, FTIR, Raman spectra and Nano Indentor microhardness were used to characterize as- deposited thin films. The results showed that higher anodic voltage enabled to increase Si-C bond and sp³-bonded carbon atoms in the films. The sample grown at 2.0 kV exhibited Si/C ratio of nearly 1 from XPS results, a pronounced Si-C peak in the FTIR spectra, only a weak peak at 1420 cm^-1 and no other graphite peak in the Raman spectra, the microhardness of 25.2 GPa.

Ultra-thin erbium layers are formed on Si(100) substrate by depositing 0.5 approximately 3 ML Er atoms in an ultra-high vacuum system. The films deposited at room temperature are in the amorphous form. After annealing at low temperatures, ordered structures form on the surface. The surface reconstruction is studied by in situ reflection high energy electron diffraction (RHEED). The transition of the RHEED patterns from (2X1) to (4X2) is observed with the increase of Er coverage up to 1 monolayers after low temperature annealing. Several cluster models are adopted for simulating Er adatoms located at different sites on Si(100) substrate to determine the favorable surface geometry. The first principle discrete variational cluster method based on ab initio local density approximation is used to calculate the total energies of different surface configurations.

By forming platinum siliside of on n-type silicon plates are created Solar Elements with a Shottky barrier. Siliside of platinum with mono and polycrystalline structure are received. The crystalline condition of the siliside was determined by electron-graphical method. The influence of background temperature to parameters of preparing elements have been investigated in the temperature range of (100 - 300)D'Alembertian. It was obtained that ideality factor (n) and open circuit voltage (U D'Alembertian D'Alembertian) are increased, but short circuit current (I_sc) is not changed with decreasing of temperature. It was established that the temperature dependence of solar elements parameters are strongly display in polycrystalline siliside.

InGaAsP/GaAs SCH SQW lasers have been prepared by LP-MOCVD. The dependence of threshold current density (J_th) on cavity length (L) was explained by threshold current condition and gain characteristics diodes samples with output power of 1 to 2 W, threshold current density (J_th) of 330 to 450 A/cm² and external differential quantum efficiency ((eta) _d) 35% to 75%, are in good agreement with the designed requirement.

In the paper, development on MBE-based SiGe/Si heterojunction bipolar transistors (HBT) is described. The SiGe/Si film used in the present work was grown by SIVA32 molecular beam epitaxy system made in Riber, France. 3 micrometers process technology with poly-silicon emitter was used to develop SiGe HBT devices. The experimental results indicated that both the direct current characteristics and the cutoff frequency of SiGe HBT are satisfactory. The current gain (beta) of HBT devices is 50, when the collector voltage V_c equals 2V and the collector current I_c equals 5 mA. The cutoff frequency f_T equals 5.1 GH_z. And the uniformity of the cutoff frequency of HBT is quite good.

Cadmium selenide thin film transistors were fabricated using normal evaporation and sputtering technique in multiple pumpdown of vacuum systems. The device structure, materials of each layer and deposition conditions are depicted. Characteristics of CdSe TFTs were studied. The results indicate that stable CdSe TFTs with good characteristics can be obtained by use of simple vacuum deposition processes and adding indium thin layer in the insulator/semiconductor interface.

The lasing modes and the spontaneous emission factors of microdisk lasers are analyzed simply, in this paper, InGaAs/InGaAsP multiple quantum wells (MQW) microdisk lasers are fabricated by using the methods of active ion etching and selective chemical etching. The diameter of the microdisk lasers was 3 micrometers . InGaAs/InGaAsP MQW microdisk lasers was optically pumped when cooled with liquid nitrogen. We obtained the single-mode lasing at 1.5 micrometers wavelength, with threshold pump power 18 (mu) w.

N-type ZnTe films with resistivities of 2 and 13 (Omega) cm have been grown by metalorganic vapor phase epitaxial technique using triethylaluminum. The photoluminescence spectra from these films exhibit strong excitonic emission and donor-acceptor-pair emission associated with Al donor and very weak deep emission band due to the Zn vacancy and Al donor complex. We have examined various metals (Al, Mg and W) and an alloy (In-Hg) for ohmic contacts to n-type ZnTe. From the current-voltage characteristics between two contacts at room temperature for above-mentioned metals and alloy, it has been found that acceptable contacts are formed using W and In-Hg alloy. The best contact among the investigated electrodes is achievable by using W electrode.

The pattern of light induced degradation, i.e. the degree of degradation of a-Si:H pinpin solar cell parameters were studied on different i-layer thickness using high intensity (approximately 10 AM 1.5) illumination. It was found that stacked cells do not show a uniform degradation pattern as in the case of single junction solar cells. In particular, the degradation in short-circuit current Isc of stacked cells shows a big difference for thick (approximately 500 nm) and thin (approximately 400 nm) pinpin cells. It was found that degradation of the stacked cells with thick bottom layers exhibit a degradation pattern similar to that of single junction cells, i.e. the degradation in efficiency comes from the fill factor and the short circuit current, while open circuit voltage being degraded slightly. The degradation in short circuit current of cells with thin bottom layers is negligibly small.

The paper has analyzed the light waveguide characteristics of microdisk lasers with the light ray theory for the first time, obtained the same result derived by Helmholtz wave equation theory and it is in good agreement with experimental results.

Structural dependence on annealing of a-SiO_x:H was studied by using infrared absorption and Raman scattering. The appearance of Raman peaks in the range of 513 - 519 cm^-1 after 1170 degree(s)C annealing was interpreted as the formation nanocrystalline silicon with the sizes from 3 - 10 nm. The Raman spectra also show the existence of amorphous-like silicon phase, which is associated with Si-Si bond re-construction at boundaries of silicon nanocrystallites. The presence of the shoulder at 980 cm^-1 of Si-O-Si stretching vibration at 1085 cm^-1 in infrared spectra imply that except that SiO₂ phase, there is silicon sub-oxide phase in the films annealed at 1170 degree(s)C. This sub-oxide phase is located at the interface between Si Crystallites and SiO₂, and thus support the shell model for the mixed structures of Si grains and SiO₂ matrix.

Some newly obtained photoluminescence (PL) data from the ZnSe:Cl epilayers grown by molecular beam epitaxy are reported here. The PL spectrum at 10 K is dominated by a strong and narrow Cl⁰X peak at 2.797 eV with the FWHM of about 13 meV. The quenching tendency of Cl⁰X peak with the increasing temperature is clearly characterized by two temperature regimes, corresponding to two thermal activated nonradiative mechanisms with activation energies of about 16 meV and 90 meV respectively. The weak emission at 2.713 eV is thermally quenched by the presence of nonradiative center with the same activation energy of about 90 meV as the Cl⁰X. The similar quenching tendency of the 2.713 eV emission and the Cl⁰X peak implies that they are quenched by the same physical mechanisms.

We have studied the energy band transitions between confined sub-bands in 10 nm surface quantum well based on in-situ Photo-modulated Reflectance (PR) Spectrum in Molecular Beam Epitaxy system. The single surface quantum well (SQW) is confined by the vacuum on one side and by Al_xGa_1-xAs barrier on the other side. The structure parameters of the SQW are monitored by the Reflective High- Energy Electron Diffraction (RHEED) during growing procedure. In PR spectrum, we have observed clearly the transitions from the hole sub-bands to the electronic sub- bands. The transition of excitation states is first observed in single surface quantum well. The results are well explained by the effective mass approximation with parameters provided by RHEED.

Based on empirical rules for the intrinsic absorption coefficient and refractive index of Hg_1-xCd_xTe in Hougen's model, a novel calculation method determining the composition profile of epitaxy layer from room- temperature infrared transmittance spectroscopy is presented. The composition depth profile of Hg_1-xCd_xTe film samples grown by liquid-phase epitaxy and after annealing is determined using this method. The expression of the composition interdiffusion coefficient for Hg_1-xCd_xTe was deduced.

Thermal capture and emission processes of Sn-related DX centers in Al_xGa_1-xAs (x equals 0.26) were measured by a constant capacitance voltage transient in various temperatures. By employing a Laplace defect spectroscopic method, the non-exponential transients were decomposed into several discrete exponential components. The results shown that more exponential components appeared int he small emission rate region as capture period increased. This indicates that electrons preferentially fill shallow energy levels due to their lower capture barriers. Discrete exponential components of the capture process were identified and four of their barriers were preliminarily measured to be about 0.14, 0.15, 0.16, and 0.17 eV, respectively.

The photoluminescence properties of ultrathin CdSe layer were reported in this paper. Several monolayers of CdSe well layer were deposited in ZnSe matrix by lower-pressure metalorganic chemical vapor deposition. Two peaks were observed in the ultrathin structure. It was considered that the high-energy peak came from the exciton combination in the ultrathin CdSe well layer and the low-energy peak might come from the interface or impurity. The decrease of growth periods could lead the peak value of exciton peak red shift and the full-width at half-maximum become narrow. This was codetermined by the effect of interdiffusion and interface roughness or well width fluctuation.

Donor-acceptor pair (DAP) in wurtzite GaN films grown by radio frequency plasma assisted molecule beam epitaxy on sapphire substrates using low temperature GaN buffer layers have been studied using photoluminescence. The energy levels of N vacancy, as donors, were calculated using an approximate formula, and good agreement with DA emission results. Native defects related to DAP and their formation energies were discussed.

The photothermal ionization spectroscopy (PTIS) has been employed to study Be shallow acceptor states in GaAs grown by MBE. We have observed the G line, D line and C line transitions which are from the ground state 1s_3/2((Gamma) ₈⁺) of Be acceptor to the first three excited odd-parity states 2p_3/2(Gamma) ₈^-), 2p_5/2((Gamma) ₈^-) and 2p_5/2((Gamma) ₇^-), respectively. The transition from the ground state 1s_3/2((Gamma) ₈^-) to the excited state 2p_1/2((Gamma) ₆^-) is identified as well. According to the PTIS, we deduce the binding energy of Be ground state in GaAs is 28.6 mev.

We have studied the longitudinal optical phonon-plasmon coupled (LPP) modes in device quality GaN epitaxy thin films deposited on sapphire substrate using infrared reflection spectroscopy. By theoretical calculation and fitting with the experimental IR reflection spectra for a series of Si doped GaN epilayers we obtain the phonon vibration parameters and the plasmon frequency and damping constant in GaN. The LPP modes have been deduced by the imaginary parts of the reciprocal dielectric function in IR reflection measurement. Both high and low branches of the LO phonon- plasmon coupling mode (LPP⁺ and LPP^-) are well resolved. With the increase of doping level, the frequency of the LPP⁺ mode shifts to higher while that of the LPP^- mode trends toward TO phonon of GaN. The carrier concentration and mobility in GaN have also been deduced. The IR measured concentration of carriers coincides with the Hall measurement. The mobility ratio of Hall to IR is about 1.75 approximately 1.96, implying a dominating mechanism of ionized impurity scattering. Raman measurement has also been performed on the same series of samples. The spectral reveal the similar behavior of the LPP modes to that in IR measurement. Our results show that both IR reflection and Raman scattering are powerful and nondestructive tools to investigate the carrier properties in GaN thin films.

Micro-photoluminescence ((mu) -PL) experiments have been carried out on the cleaved facet of quantum well infrared photodetector to extract multiple quantum well signal. Some structures and peak response wavelength have been estimated by a numerical calculation based on the square well model. Thus, a relationship between PL spectrum and parameters was built.

In this paper, photoluminescence (PL) measurements were performed on several series of single-side Si doped MBE pseudomorphic high electron mobility transistors (p-HEMTs) quantum well samples, with different spacer layer widths, well widths and Si (delta) -doped concentrations, under different temperatures and excitation power densities. PL signals from the transitions of the second electron subband to the first heavy-hole subband (e2-hh1) and the first electron subband to the first heavy-hole subband (e1-hh1) have been observed with good symmetry and narrow full with at half maximum indicating high sample quality compared with previous reported results. The dynamic competitive luminescence mechanism between the radiations of e2-hh1 and e1-hh1 was discussed in detail. The confining potential, subband energies, corresponding envelope functions, subband occupations and transferring efficiency have been calculated by self-consistent definite differential method at different temperatures in comparison with our experiment results. The relative variation of the integrated luminescence intensity of the two transitions (e1-hh1 and e2-hh1) was found to be dependent on the temperature and the structure's properties, e.g. spacer layer width, dopant concentration and well width, which is an efficient characterization method before p-HEMTs device fabrication.

Polarization-sensitivity of electroabsorption (EA) modulators is analyzed by fractional-dimensional approach. Chirping parameter (alpha) is then calculated using Kramers- Kronig relations. It is found that polarization insensitive and negative chirp operation can be realized simultaneously for InGaAsP multiple-quantum-well EA modulators with optimized well width and amount of strain. We propose a polarization insensitive InGaAsP EA modulator with 9 nm wide 0.38% tensile-strained quantum wells. The modulation characteristics remains polarization independent up to 80 kV/cm, corresponding to an extinction ratio of over 15 dB, and the chirping parameter (alpha) is estimated to be around -0.25.

The GaN growth and Si-doped GaN are studied in this work. By means of x-ray diffraction and photoluminescence (PL) measurements we found that the GaN sample directly grown on GaAs substrate is pure cubic phase and that grown on AlAs buffer is pure hexagonal phase. The present study shows that the phase of GaN samples grown on GaAs substrates can be controlled using different buffer layers. The PL properties of Si-doped cubic GaN with different carrier concentrations were investigated at room temperature. It was found that when the carrier concentration is increased from 5 X 10¹⁵ to 2 X 10¹⁸cm^-3, the PL peak shifted towards low energy, from 3.246 to 3.227 eV, and the PL linewidth increased from 77.1 to 121 meV. The PL peak shift is explained by the bandgap narrowing effect due to the high doping concentration. The PL linewidth includes two parts: one is doping concentration-independent, which is caused by the imperfection of samples and phonon scattering; the other is doping concentration-dependent. We assign the second part to the broadening by the microscopic fluctuation of the doping concentration. The experimental measurements are in good agreement with the model.

The recent progress in MBE growth of HgCdTe at the Research Center for Advanced Materials and Devices, and the National Laboratory for Infrared Physics is reported. It is found that the excellent compositional uniformity and reproducibility of HgCdTe can be archived by MBE technique. The results of surface morphology, dislocation density, electrical properties and focal plane array detectors are described in the paper.

Room temperature operation of Nb/Nb oxide-based single- electron transistors (SETs) was successfully achieved and was reported in detail. First, the SETs were fabricated by a scanning probe microscope (SPM)-based anodic oxidation technique, and then the junction area was further reduced by thermal oxidation. Ultra-small tunnel junctions were easily obtained by utilizing these two kinds of oxidation processes, and clear single-electron charging effects were observed through the Nb/Nb oxide-based SETs at room temperature.

The influence of glow discharge hydrogen plasma processing on undoped tin dioxide (SnO₂) thin film structure and properties have been investigated. The films of 150 - 200 nm thickness were deposited by a method of magnetron sputtering on Al₂O₃ substrate at the temperature of this one 250 degree(s)C with a rate of 1.5 - 2.0 nm/min in argon-oxygen mixture atmosphere. It was shown these films are amorphous just after fabrication, theirs polycrystalline structure appears after annealing and disappears after processing in the hydrogen plasma. Such a processing expands a temperature range of film sensitivity to ethanol and heptane vapors, increases the sensitivity to low concentration of those.

The photoemission characteristics of aluminum (Al) and gold (Au) thin film photoelectric cathodes were studied. The metallic cathode stability after exposed to air was investigated. The results of the experiments and study on its photoemission were given, and the application prospect of surface emitter in near UV region was proposed.

The atomic processes of nucleation and initial growth of thin films on metal surfaces are simulated by Monte Carlo method, using realistic growth model and physical parameters. The effects of adatoms evaporation from the substrate and diffusion along the edge of the islands are included in the simulation model. It is shown that the compact structure of Fe island grows on Fe(001) surface over the wide range of temperatures from 250 to 2000 K, which is consistent with the nucleation theory. The simulation results not only nicely reproduce the experiments of thin film growth at intermediate temperature, but also predict the growth situations of thin films at high temperature.

By using the MOM device of Bi₂O₃ films, some electrical properties on these films or the device are studied as follows: (1) The behavior of the electric current across the thick Bi₂O₃ films under DC field, is elucidated by the formula Ivaries direct asVⁿ for the regions of low (n equals 1), ohmic (n equals 1), high (n > 2) conductivities and SCLC (n >= 1.5 approximately 2). A hysteresis of the I-V curve results from the residual space charge and polarization in the device. (2) The memory switching and oscillation (in CCNR) phenomena on the device of thin Bi₂O₃ films are observed under the AC applied voltage in the room temperature and 77 K. These rest upon a thermal effect due to the current injection to the device.

Enhancement of the free-space diffraction efficiency of titanium-ion implanted gratings by inserting them into multilayer dielectric Fabry-Perot cavities has been demonstrated theoretically in previous works. In this paper, we discuss the sensitivity of the diffraction efficiency to the optogeometrical parameters of the structures obtained using titanium-ion implantation. A process to perform a phase grating in a seven-layer mirror Fabry-Perot cavity is described and experimental results pertaining to efficiency measurements on this structure are compared to numerical simulations.

A tunneling magnetoresistance of Fe-SiO₂ granular films was studied. The samples were prepared similarly by the preparation of multilayer films using two disks of Fe and SiO₂ sputtering targets. The superparamagnetic feature and tunneling magnetoresistance were observed for the samples with Fe composition rate of lower than 0.45. Small Fe granules isolated by SiO₂ matrix were observed by the transmission electron microscope. The magnetoresistance curves of these samples exhibited `two step' resistivity change, which was not observed from the annealed sample. This unique feature of tunneling magnetoresistance at a low magnetic field was presumably attributed to the existence of 2D structure of granules.

In order to improve the magnetic properties of Co-based thin films, different seedlayers (SiO, ITO, SiO₂, Ag and Al) have been applied on a PET substrate. The thickness of Cr underlayers and of magnetic layers is varied to obtain thin films with optimal magnetic properties. The magnetic properties of CoCrTa and CoCrPt thin films are improved clearly when the magnetic layer is thin. Specifically, the coercive force of CoCrPt thin films reaches 100 kA/m sputtered with a sputter pressure 50 mTorr on pure argon at room temperature. AFM topographies indicate that the average grain size and the grain shape of thin films vary with thickness of Cr underlayer and of magnetic layer. This influences the magnetic interactions inside thin films and subsequently adjusts the magnetic properties. The crystal structure of each thin film with a seedlayer is improved as well.

For prepared Fe_xAg_100-x granular films, the Kerr rotation and ellipticity change monotonically with the photon energy and after annealing have two peaks near 2.0 and 3.8 eV, respectively. The peak value increases with annealing temperature T_A. Numerical calculations show that the peak at low energy is induced by the change in the off-diagonal element of dielectric tensor of Fe particles and the peak at high energy results from the changes in optical properties of Ag particles near its plasma absorption edge. These results clearly show the simultaneous existence of both the magneto-optical size effect of Fe particles and optical size effects of Ag particles in metallic granular films.

Thin films of tungsten used as buffer layers for diamond coating on tool steels have been prepared by rf magnetron sputtering. The tungsten deposition rates as functions of argon pressure and rf input power are reported. The effects of argon pressure and rf input power on the film structures have also been studied. Finally, it has been demonstrated that continuous diamond films can be grown on tool steels by using tungsten films as buffer layers.

Oxide growth on rare-earth erbium film at room temperature was quantitatively followed by means of quartz oscillation technique. Structure and chemistry of the oxide layer were characterized by x-ray diffraction and x-ray photoelectron spectroscopy. The humidity in oxidizing environment is found to be the key factor leading to the increase of oxidation rate of the erbium film. The oxide layer is composed of crystallites of erbium and erbium oxide. The O 1s photoelectron spectra are characterized by two components that are assigned to oxide and hydroxide species respectively. The oxide layer shows a layered structure with an oxide layer covered by a hydroxide overlayer.

The effect of argon ion bombardment on interface of silver and high oriented pyrogenic graphite (HOPG) was investigated by atomic force microscopy. The Ag/HOPG interface morphology has been explored as a function of irradiation time. It can be seen that the size of crystal particle on HOPG is almost unchanged with increase of irradiation time, while the size of Ag crystal particle in part of the terrace increased and became highly ordered. There is no obvious mixing between Ag and HOPG, and Ag particles in nanoscale are isolated on HOPG surface. This will result in the reduction of depth resolution of the surface analysis by ion sputtering technique.

The structure and the electrical bistable properties of vacuum deposited thin films of Ag-TCNQ (7,7,8,8- Tetracyanoquinodimethane) complex have been investigated. The characteristics of obtained films under different preparation conditions have been compared. The optical transmission spectra and the x-ray diffraction measurements were conducted to analyze the structure and the thermal stability of the films. The atomic force microscope was used to examine the morphology and grain size of the films. The corresponding electrical switching property was measured upon the Ag-TCNQ films with different combined sandwich- shaped electrodes. The results how that the films can have very stable switching properties. The switching time between high and low impedance states is about 10 ns, and the switching voltage is around 4.0 V. The film preparation parameters and different layered structure have an important influence on the characteristic of the films. The switching mechanism was discussed.

Island silver films (nanoclusters, quantum dots) embedded in silica are prepared on silicon wafers and glasses by sputtering. Atomic force microscope is used to characterize the morphology and distribution of silver nanoclusters, the size of nanoclusters varies from several ten to several hundred nanometers. Linear optical absorption spectra of annealed samples have a blue-shift compare to that of as- prepared samples, it suggests thermal treatment decomposes large clusters to small clusters. Z-scan technique is applied to study the third-order non-linear optical properties. It is found that the embedded silver nanoclusters present remarkable third order nonlinear effect even if the size of silver nanoclusters are as large as several tens to several hundreds nanometers. Thermal treatment leads to a slight reduction in NRIC, indicating annealing also dissolve tiny nanoclusters. The size distribution of silver nanoclusters therefore becomes centralized after thermal treatment.

Aluminium oxynitride thin films have been produced by using a reactive dc magnetron sputtering system incorporating a microwave plasma to improve the ionization of the reactive gases. This allows films of high optical quality to be deposited at commercially acceptable deposition rates. A series of homogeneous films of aluminium oxynitride films covering the range of compositions from aluminium oxide to aluminium nitride have been prepared and their optical constants characterized over the wavelength range 300 nm to 1500 nm. As a demonstration of the stability and reproducibility of the system, some complex graded-index optical filters have been designed and fabricated using a simple control program based only on setting the gas flows and times for each layer. The experimental results are shown to agree very well with theoretical results based on the dispersive optical constants of the individual layers.

More than ten kinds of oxide thin films and their heterostructure have been successfully fabricated on SrTiO₃ (001) substrates by laser molecular beam epitaxy. Measurements of atomic force microscopy, high-resolution transmission electron microscope and x-ray small-angle reflectivity reveal that the surfaces and interfaces are atom-level-smooth. The unit cell layers and the lattice structure are perfect. The enhancement of second-harmonic generation in BaTiO₃/SrTiO₃ (BTO/STO) superlattices and the thickness dependent structural characteristics of BaTiO₃ (BTO) thin films were observed.

The effectiveness of Single Source Chemical Vapor Deposition as a one step process for producing zinc oxide films on silica fibers was evaluated. The physical and chemical properties of films grown on optical fibers and films grown on planar silica substrates under identical conditions were probed for differences using X-Ray Photoelectron Spectroscopy (XPS), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The XPS analysis of the film surface and bulk found no significant variation in the chemical composition between films grown on planar substrates and films grown on optical fibers. The XRD of films grown on planar silica substrates showed these films to be composed of crystallites roughly 30 - 40 nm in size and oriented in the c-axis direction. SEM revealed some differences in the morphology between standard grown on planar silica substrates and growth on silica fibers although films in both cases were composed of columns of crystallites. Although it was found that film thickness varied around the circumference of the silica fiber relative to the position of the precursor source, the films were nevertheless continuous and consistent in chemical composition.

Titanium dioxide films were deposited onto Si(100) substrate by plasma enhanced chemical vapor deposition. Titanium isopropoxide (Ti(OC₃H₇)₄ was used as precursor. Argon was used as a carrier gas for the precursor and the reactant for the plasma process. The deposition rate was studied as functions of deposition parameters such as r.f. power, substrate temperature, carrier gas flow rate. The structures of the films were characterized by x-ray diffraction and by Raman scattering. The thickness and refractive index of the films were characterized by ellipsometry. It was found that the refractive index of the films increased from 1.8 to 2.5 with substrate temperature range from 150 degree(s)C to 700 degree(s)C. And it increased monotonically with annealing temperature range from 400 degree(s)C to 900 degree(s)C. Films deposited onto Si(100) substrates were amorphous at substrate temperatures between 80 degree(s)C and 200 degree(s)C, a mixture of anatase and amorphous at 230 degree(s)C - 450 degree(s)C, anatase between 500 degree(s)C and 600 degree(s)C, and only rutile above 650 degree(s)C.

With MgO film as an example, the effect of different technical parameters in preparation of protecting film overcoating the dielectric layer in AC PDP (Plasma Display Panel) by electron-beam evaporation method on the performance of AC PDP are thoroughly studied and discussed in this paper. These parameters explored include the substrate temperature, the deposition rate, etc. The relation between the composition, the crystal structure, the appearance of protecting film and emissive properties is researched, and their influence on the properties of AC PDP is also studied, the optimal process of preparing film is examined. And also this observed dependence of the discharge characteristics on the various parameters of the panel fabrication process is explained in terms of a postulated effect of oxygen on the surface properties of MgO films and the changes in the surface properties of the MgO films produced by ion bombardment during the discharge.

ZrO₂ thin films were prepared by sol-gel technology from suitable zirconia aqueous colloidal suspensions containing nano-crystalline ZrO₂ at room temperature synthesized by hydrothermal process from inorganic precursor (ZrOCl₂ (DOT) 8 H₂O). By adding a soluble organic binder PVP to the suspension prior to application, it substantially increased the coating refractive index and the abrasion- resistance as well as the laser damage threshold. The features of the coatings and the colloidal suspensions were investigated. Multilayer highly reflective dielectric coatings were also elaborated by laying down quarterwave- thick alternating coatings of the binder-aided zirconia and silica, which was prepared with the sol-gel process from TEOS. Laser damage thresholds of 20 and 18 J/cm² (1064 nm, 1 ns) were achieved for single ZrO₂-PVP coating and ZrO₂-PVP/SiO₂ multilayers respectively.

Ti was prepared on substrates by sputtering methods, then followed by an oxidization step to form TiO_x. TiO₂ films with dopents (In, Ta and Nb ions etc.) or without, could be directly coated on the surface by TiOx by a sol-gel process to obtain the films with TiO_x-TiO₂ structure. TiOx films in the oxidation process of Ti were calculated by diffusion equations and analyzed by x-ray diffraction. Crystalline phases, grain size and morphology of TiOx,-TiO₂ cross section have been observed by transmission electronic microscopy and scanning electron microscopy, respectively. Raman spectra of the films with the dopants demonstrated existence of anatase phase even in nigher temperature. The electrical properties of the films were analyzed and compared with each other. The results have been explained by transferring theory of the excitons with the structure.

Thin films of ZrO₂ were deposited from aqueous solution on Si(100) substrates precovered by alkyltrichlorosilane self-assembled monolayers. The interface structure, thermal stability and densification of these films in the temperature range from room temperature to 750 degree(s)C in vacuum were measured using in situ x-ray reflectivity. The growth rate is a nonlinear function of time in solution. Decreasing film thickness and increasing density is found upon annealing up to 750 degree(s)C. A 25 nm film revealed the appearance of a mixed-phase crystalline structure at 800 degree(s)C which disappeared upon cooling. There is no visible evidence of stress-induced microstructural changes, such as peeling or cracking.

Nickel oxide films were deposited onto indium-tin oxide coated substrates by electron-beam evaporation and were electrochemically colored and bleached in KOH electrolyte. X-ray diffraction, infrared, x-ray photoelectronic and Raman spectroscopy were used to characterize the films. Results show that the as-deposited films are composed of crystallites with preferential orientation of cubic NiO(111), and retain their original structure after electrochromic redox reaction. The boundary and surface of the NiO crystallites play a critical role in the electrochromic reaction, the sites of the injection and ejection of OH^- ions and relevant electrochromic reaction are at the interface of NiO crystallites, the major composition at the interfaces of the crystallites are NiO for the as-deposited films, NiOOH for the colored films and Ni(OH)₂ for the bleached films.

The optical sensitive characteristic of SnO₂ and V₂O₅ thin films to the gas SO₂ was investigated with photometric and ellipsometric methods. It is found that thin films of the Pd-doped SnO₂ and pure-V₂O₅ have good optical sensitive characteristics to SO₂ in the visible range, and the Zr-doped SnO₂ film in the near-infrared area. The results show that the change of the optical characteristic is directly related to the variation of optical gap and the concentration of free carrier in thin films.

Photoluminescence of thin crystalline TiO₂ films was studied. The films contained an anatase phase and were grown by the atomic layer deposition method on different single crystal substrates. A polarized re-combination emission of self-trapped excitons was observed in the films at 5 K. A comparison of the obtained spectra with those of the single crystal anatase allowed determining crystallite orientations in the films. Results were consistent with the x-ray diffraction and reflection high-energy electron diffraction data.

Sol-gel spin-coating technique was applied to produce tantalum pentoxide thin films. Pseudo-ternary phase diagrams were used to outline the sol-solution stability and the optimal Ta₂O₅ thin films formation regions of Ta(OC₂H₅)₅-C₂H₅OH- CH₃COOH-H₂O system. Forbidden band gap of Ta₂O₅ thin film was calculated and found to be Eg equals 3.7 ev. Room temperature cyclic voltammetric measurements clearly revealed a protonic conductor behavior for Ta₂O₅ thin films.

The aim of this study was to determine the optical properties of WO₃ and Zr doped tungsten oxide films deposited by the sol-gel process. The optical properties of WO₃ and Zr doped tungsten oxide films deposited by the sol-gel process depend on the number of coating layers. The refractive index and absorption coefficient of WO₃ thin films increases with an increasing number of deposited layers. Transmittance of Zr doped tungsten oxide thin films are greater than tungsten oxide thin film. A scanning electron microscope was used for the analysis of surface structure. Optical constants of tungsten oxide and zirconium tungsten oxides were determined by using spectrophotometric transmissivity in the UV-Visible region.

TiO₂ thin films were deposited on glass substrates by the sol-gel process using spin-coating technique. Three kinds of sol systems were used to produce the films which were then baked at various temperatures. Water contact angles of the films were measured using the tilting plate method. The initial water contact angle of an as-prepared film was < 5 degree(s), and after a certain period of placement it started to increase gradually up to a maximum of 72 degree(s). Water adsorption was found to accelerate the increase of the contact angle. Appropriate UV light irradiation could make the high (72 degree(s)) water contact angle of the film return to the initial value, i.e., < 5 degree(s). Films prepared with DEA-chelated precursors have higher speed of increase in the water contact angle than those prepared with AcAc-chelated precursors or without any chelating agent. AFM images showed that the surface roughness of these films were different, suggesting that the surface roughness is another factor affecting the wettability of the films.

A new technology and method preparing ions barrier film on the input face of multi-hole substratum, MCP, without carbon pollution were studied and introduced in this paper. The composition of the film and the performance of MCP coated with ion barrier film were tested by XPS and UV photoelectric emission method. The new process made the carbon content largely decrease in the film, and the characteristics of MCP unmodified.

In order to decrease the cost of AC PDP by using low voltage driving system, using an measuring system which can imitating AC PDP operating, the influence of protecting film prepared by different materials on discharge characteristics in AC PDP are explored. The studied materials include MgO which commonly used in AC PDP, new materials--compound alkaline earth oxides with different proportion, such as (CaSr)O and (MgSr)O. In this paper, the study direction of new film materials id determined, and the problems must be dissolved in using the high emissive materials film are investigated.

With MgO film as an example, the effect of different heat treatment conditions in preparation of protecting film overcoating the dielectric layer in AC PDP (Plasma Display Panel) prepared by electron-beam evaporation method on the performance of AC PDP are thoroughly studied and discussed. The studied baking condition mainly focuses on treating atmosphere, air, vacuum, and inert gases atmosphere are considered. And also this observed dependence of the discharge characteristics on heat treatment condition of panel fabrication process is explained in terms of a postulated effect of oxygen on the surface properties of MgO films and the changes in the surface properties of MgO films produced by ion bombardment during discharge.

Iridium oxide (IrO₂) thin films were successfully grown on SiO₂/Si(100) substrate by DC magnetron reactive sputtering method with an Ir target (99.99% purity). The effects of sputtering parameters and annealing conditions on the crystalline nature and morphology of IrO₂ thin films were discussed. High orientation at (110) or (200) of IrO₂ thin films were occurred by annealed films. For fatigue properties, PZT thin films using an IrO₂ electrode have largely improved than that using a Pt/Ti electrode.

Sputter deposition process conditions for dielectric metal oxide films was simulated by SIMSPUD^TM (Simulation of Sputtered Distributions). Collision cross-sections of Nb and Si were found to be 50 angstroms² and 55 angstroms² respectively by pinhole experiment and simulation. Film thickness distributions of Nb and Si films vs their oxide counterparts (Nb₂O₅ vs SiO₂) showed that the deposition rate ratio of SiO₂ to Si is 2.03 - 2.05:1 while Nb to Nb₂O₅ is 1.76 - 1.77:1. It was determined that the current density distribution and oxygen flow for reactive sputtering had great influence on film stoichiometry and thickness. It was also found that the ion source flattened the oxide film thickness. SIMSPUD was shown to be a desirable tool for new product development and as such could be beneficial in the design of the next generation PVD system.

Amorphous TiO₂ thin films with and without the doping of ZnFe₂O₄ were prepared by radio frequency magnetron sputtering. The influence of post-deposition annealing on the structural and optical properties was studied. It was established that the anatase single phase exists between 250 degree(s)C and 800 degree(s)C in the TiO₂ thin films, and between 450 degree(s)C and 650 degree(s)C in the TiO₂ thin films with 2 wt% doping of ZnFe₂O₄. The absorption edge of TiO₂ thin films with and without doping exhibits a blue shift with decreasing annealing temperature and the absorption edge of TiO₂ doped with ZnFe₂O₄ has moved to visible spectrum range. The enhanced photoluminescence of the TiO₂ films doped with ZnFe₂O₄ was found in comparison with pure TiO₂ thin films at room temperature.

The effects of sputtering conditions on magnetic properties of amorphous TbFeCo films were investigated. By fixing the current set, the sputtering power reduces with the increase of sputtering Ar pressure, and the coercivity increases with the decrease of sputtering power, in contrast to the magnetization decreases. Film deposited at an Ar pressure of 0.42 Pa and a sputtering power of 7 W develops very good magnetization loops and high perpendicular anisotropy at room and low temperature. Magnetization measurements show that the in-plane magnetization loop at 10 K becomes larger with the increase of saturation magnetic field. This may be caused by the disorder of Tb atoms. At fixed Ar pressure, the coercivity decreases with the increasing sputtering power an the magnetization loop becomes narrow at high sputtering power. The effect of film thickness on magnetization loops is also studied.

The relationship between the magneto-impedance (MI) effect and the size of amorphous FeSiB film is reported in this paper. The MI change ratio of FeSiB film is different for the three samples with different widths, and increases with the increasing of sample length when the width is fixed. Experimental results can be explained in terms of stress anisotropy and different external inductance of the sample.

The structure, crystallization processes and products of electroless Ni-Fe-P alloy deposits at various heat treatment temperature were studied, with prepared and composition. The deposits were amorphous structure with NaH₂PO₂ concentration from 18 g/L to 48 g/L. The surface of the deposited specimens was smooth, bright and homogeneous. Heating these deposits from 200 to 700 degree(s)C produces structural changes. A two-step process of crystallization was observed for the amorphous alloys. At first, the crystallization phases were (gamma) -(Fe,Ni) solid solution phases and Ni₃Fe, then Ni₃P, Fe₃P and (Ni,Fe) solid solution phases for high temperature in the films.

Some results in sandwiched Co/spacer/Co structures have been achieved. With doping Mn and NiO in the Cu spacer, the GMR curve as a function of the magnetic field changes a lot, and the saturation/switching field for GMR can be reduced greatly compare with that in Co/Cu/Co systems. The most important characteristic of the MR change for Co/CuMn/Co system was its two peaks became narrow and sharp, but for Co/NiO-Cu/Cu system, was its two peaks became wide and flat. These results may indicate some new ways in consideration of candidates for novel magnetic devices.

Mn/Sb multilayer films were grown on GaAs (100) by ultrahigh vacuum evaporation technique and subsequent thermal annealing for short duration. Structural, magnetic properties and magneto-optical Kerr effect were investigated. Magnetization measurements reveal strong room- temperature ferromagnetism even for unannealed films. X-ray diffraction patterns show high-quality crystal structure of MnSb is formed. The film annealed at 350 degree(s)C also shows the lowest coercivity and the largest saturation magnetization. Both the polar and longitudinal magneto- optical Kerr rotations are observable for annealed films and the dependence of the Kerr rotation angles on the magnetic field is nearly the same as that of magnetization.

The Giant magnetoresistance behavior of Co/CuMn/Co sandwich structures has been investigated, combined with the surface magneto-optical Kerr effect (SMOKE) method in air. Very low saturation/switching field was achieved by diluting Mn atoms into the Cu metal, but GMR value has no much change, which may imply a way to get high sensitive GMR material. The SMOKE measurements showed steps in Kerr loop, indicating the antiparallel alignment of magnetizations between two neighbored Co layers due to their different switching fields.

The experiments of Co₈₉Zr₄Nb₆₇ magnetron sputtering showed that the stoichiometric relation in deposited film is obviously different from that in target. The fact that Zr and Nb contents, which have larger atomic mass, in deposited film were more than that in target showed there were different virtual sources of Co, Zr and Nb between target and substrate.

The requirement to recording density is always increasing with the rapid development of information technology. MR magnetic head was developed under the situation. The main problem met in the application of MR read head is the Barkhausen noise due to the magnetic domain activities in sensor element. There are reports indicated that magnetic domain will tend to single domain structure when the ratio of length and height of rectangle sensor is over 20 and the problem of Barkhausen noise can be resolved. The element which length, width and height is 300 micrometers , 3 approximately 6 micrometers and 40 nm respectively with the ratio of length and height over 50 is studied by bitter powder method. We found that multi-domain activities exist in sensor resulting from the irregular shape of lead line.

There are two patterns of the transition process of Neel domain wall in magnetic thin film elements. One is the direct transition from positive polarity (N₊) to negative one (N_-). And the other pattern of N₊ yields Nct yields N_- is indirect transition process recurring to cross-tie wall (Nct). The latter pattern is observed and analyze in this paper.

Thermal stability of amorphous DyFeCo films covered with non-stoichiometric AlN layer has been investigated. When RE- dominated films were annealed in air for 10 hours at 200 degree(s)C, the Kerr loops showed the characteristic of magnetic double-layered films. This behavior can be interpreted as follows: the reaction of diffusing N with Dy leads to a reduction of the magnetic active Dy content at the interface and created a very thin TM dominated DyFeCo layer between AlN and DyFeCo layer. This interpretation was demonstrated by XPS measurements.

A series of Co_xAg_100-x granular films was prepared by ion beam sputtering and annealed at 100 degree(s)C, 250 degree(s)C, 400 degree(s)C, 500 degree(s)C, respectively. The optical constants, the complex dielectric function and magneto- optical Kerr parameters were measured at room temperature. It was found that Kerr rotation and ellipticity with increasing of the Co content. For the samples Co₁₇Ag₈₃, the strong Kerr effect enhancement is observed around the Ag plasma edge. With the annealing temperature increasing, the enhancement peak shifted toward the low photon energy region. From the analysis of the numerical calculations, it is concluded that the magneto-optical Kerr effect enhancement is due to the presence of the steep plasma edge.

Annealing effects on magnetization behaviors of amorphous TbFeCo films have been investigated by vibrating sample magnetometer. Thermal annealing at 100 degree(s)C shows that large perpendicular anisotropy and coercivity still remain after annealing, and inverse magnetostrictive anisotropy is responsible for the decrease of coercivity. It is shown that the coercivity and anisotropy decrease greatly after annealing at temperature over 130 degree(s)C, however, long time annealing does not affect the magnetic properties of TbFeCo films evidently. Annealing at 180 degree(s)C shows that the room temperature magnetization loop in perpendicular direction is similar to that for films annealed at 130 degree(s)C, but the in- plane magnetization loop becomes strong. The remains of perpendicular anisotropy may be attributed to the pair ordering anisotropy and can not be eliminated by low temperature annealing.

Giant magneto-impedance (GMI) effect has been studied in the sandwiched FeSiB/Cu/FeSiB films in the frequency range of 1 - 40 MHz. With magnetic field, H_a and AC current applied along the longitudinal direction, the field dependence of the GMI ratio shows that the GMI ratio increase with magnetic field, reaching a positive maximum value at a certain field, and then gradually decreases to the negative GMI ratio. At a frequency of 5 MHz the positive maximum GMI ratio is 1.6% at H_a equals 15Oe, and is smaller than the negative GMI ratio, -7.4% at H_a equals 50Oe. With a transverse field applied, at a frequency of 5 MHz a large negative GMI ratio, -12.2% and -15.4% are obtained for H_a equals 70Oe, respectively. The larger negative GMI ratios at relatively large fields may be associated with the dispersion of easy axis and the related domain structures.

The influence of easy axis orientation and bias field on magneto-impedance (MI) effect has been investigated in FeSiB amorphous films. The magnetic field corresponding to the maximum MI ratio shifts to a low value with the increase of the easy axis angle deviated from the transverse direction, and the sensitivity of MI change ratio to longitudinal field can be enhanced by applying a proper bias field along transverse direction.

We have conducted a systematic study of the effects of laser irradiation on the properties of crystalline and amorphous YBaCuO thin films obtained by laser deposition. The irradiation experiments were mainly performed with a KrF and XeCl pulsed (25 ns) excimer lasers producing energy densities of the order of 0.1 J/cm², but we used also Cu vapor green and Ar ion blue lasers with medium power output. In all cases the irradiation produced irreversible changes in the investigated samples. We measured structural, optical and transport properties of the irradiated films. After high dose laser treatment of crystalline (orthorombic) films their superconducting properties as a rule deteriorated, but even small dose was sufficient for a marked improvement of surface smoothness. The response of amorphous films was more complex, dependent on the substrate and relied on the presence of crystalline clusters embedded in the amorphous matrix. X-ray diffraction studies of amorphous films revealed structural transformations caused by the interaction with laser light, and the results of optical spectroscopic measurements lead to interesting conclusions concerning the band structure in the investigated materials. Photon assisted structural transformations are suggested as the possible explanation of the observed effects.

We have grown a heterostructure of YBCO/STO/YBCO on (100) MgO substrate for fabrication of SXS junction. The epitaxial YBCO films were grown by MOCVD method, and the STO layer was deposited by unbalanced magnetron sputtering method. All of films are dominated by a-axis oriented phases. The individual YBCO films revealed critical-current densities around 2.5 X 10⁵ A/cm² at 77 K. The resistive transition observed in the vertical transport devices is dominated by the X layer properties. These devices display RSJ-type I-V characteristics and the values of IcRn significantly depend on the X layer thickness. The SXS junction with STO layer of 0.1, 0.2 and 0.3 micrometers have IcRn of 115, 90 and 42 (mu) V, respectively.

High quality HgBa₂CaCu₂O_x (Hg-1212) films have been synthesized on yttria-stabilized ZrO₂ substrates by using YBa₂Cu₃O₇ (YBCO) as a buffer layer. These films with Hg-1212 as the major phase were found to possess Tc (R equals 0) > 115 K and Jc approximately 10⁶ A/cm² (at 77 K). The X-ray diffraction patterns indicated that the obtained films have an in-plane epitaxial structure with the c-axis perpendicular to the film surface. The morphological investigations on the film surfaces have revealed the occurrence of layered spiral-like growth features. The influence of the YBCO buffer layer on the growing of Hg-1212 films is discussed.

The 4 X 4 element arrays based on high Tc superconducting infrared microbolometers have been fabricated using the micromachining technology. The detectivities D* for various bolometric elements are ranged from 1.2 X 10⁸ to 7.2 X 10⁸ cmHz^1/2w^-1 at the operating temperature approximately 88 K.

Synthetic diamond films grown by vapor-phase growth have attracted much interest because of promising applications in electronic devices. Improvement of film quality by reducing the number of crystal defects and impurities is the most important prerequisite for successful device applications. Defects and impurities produce deep states in the wide band gap of diamond. These mid-gap states decrease the efficiency of edge emission and exhibit `visible' luminescence. Recently, it has become possible to obtain high-quality diamond films that show phonon-assisted exciton recombination radiation from the indirect edge. The analysis of edge emission spectra can be used to characterize crystallinity and purity of synthetic diamond films. We have studied band edge structure of synthetic diamond films of differential reflectance spectroscopy as well as cathodoluminescence. The differential reflectance spectrum obtained from a high-pressure-high-temperature synthetic diamond shows interband transitions assisted by phonon emission. On the other hand, chemical vapor deposited diamond films show a zero-phonon exciton transition together with the phase-assisted transitions. This indicates light absorption by bound excitons due to crystal defects. Furthermore, we have investigated higher interband transitions localized in the Brillouin zone by a newly developed electron-beam electroreflectance spectroscopy.

Since (beta) -C₃N₄ has been predicted to be a superhard material with a higher hardness than diamond, many research groups have attempted to synthesize carbon nitride materials. We have prepared amorphous carbon nitride (a-C:N) films by rf magnetron sputtering of graphite with N₂ as the sputter gas. In this investigation, a series of film samples have been deposited at different rf power. AFM images have shown that the higher the rf power, the bigger the cluster size on the films and the rougher the surface of the films. By analyzing the results of our XPS experiments, we have found that with the decrease of the rf power, not only the incorporated nitrogen but also the concentration of sp³-bonded nitrogen in the films increased. We believe this is because f lower rf power results in smaller carbon clusters on the surface of the films, leading to larger carbon surface area. A larger film surface area makes it easier for the nitrogen to bond with carbon.

In this work we discuss thin film amorphous carbon which is deposited in a dual frequency plasma enhanced CVD system with a nitrogen-containing ambient. Unlike most carbon films deposited using PECVD, the films in this study were deposited on the grounded electrode and therefore subject to little energetic bombardment during growth. Methane was used as the carbon-containing precursor. We illustrate some potential applications for this type of film and discuss the effect of various process parameters on resulting film properties, such as optical constants, stoichiometry, and chemical bonding and structure.

In this paper, the SiC_xN_y films were prepared by RF magnetron sputtering with SiC target. The influences of the basic process parameters on the deposition rate and optical properties were studied. The results revealed the formation of a complex network among Si, C and N. The deposition rate decreased with increasing partial pressure of nitrogen. The increase of N₂ flux resulted in the wider optical gap. The greater the sputtering power, the higher the deposition rate and the narrower the optical band gap.

In this paper homogeneous and dense diamond films with good crystalline quality are successfully deposited on porous silicon surfaces by the microwave plasma assisted chemical vapor deposition method. Photoluminescence measurements show that the CVD diamond film-coated porous silicon has a weak shift of emission wavelength as compared with the stored porous silicon without a diamond film, and its PL intensity almost doesn't change with time. It means the diamond film can efficiently stabilize the PL wavelength and intensity of porous silicon and provide a better passivation effect. In addition, due to its well-known high hardness, the CVD diamond film can improve the mechanical strength of PS surface, and is therefore a promising candidate for passivation of porous silicon in the future.

Bombardments of hydrogen and boron ions are performed by applying a negative bias voltage to the substrate during microwave plasma chemical vapor deposition process. The size of (001) faces increases after hydrogen ion etching, while other grains are etched off. The surfaces of [001]- oriented films after boron dying are investigated by scanning electron microscope and cathodoluminescent (CL) spectra. The absence of the band-A emission in the CL spectra means a low density of dislocations in the films. It is the first time to indicate that the peak at 741.5 nm and the broad peak at around 575 and 625 nm in the CL spectra are reduced efficiently after boron doping in (001) polycrystalline diamond films. We propose that these phenomena could be explained in simple terms by a penetration or adsorption model through the lattice nets of the [001]-oriented surfaces.

SiC material is of intense interest because of its unique properties. Two samples were prepared by carbon ion implantation into silicon substrates with a metal vapor vacuum arc ion source at an energy of 65 keV and a dose of 1.0 X 10¹⁸ cm^-2. Following implantation, one sample was annealed in nitrogen ambient at 1250 degree(s)C for 10 hours. Spectroscopic ellipsometry (SE) was performed on these two samples (as-implanted and annealed) over a spectral range of 400 - 2000 nm at a fixed incidence angle. In order to lessen the parameter correlation existing in the regression analysis, a multiple sample analysis method was employed. From the interpretation of SE spectra, structural and optical properties of the annealed and the as-implanted samples were derived. SE results confirmed the formation of a thick buried SiC layer for the annealed sample, but the optical properties of this buried layer were found to be different from those of bulk SiC material. For the as- implanted sample, the gradual carbon atom profile was simplified homogeneous composition layers with varying carbon concentrations. The carbon-rich region was treated as a single layer whose optical properties can be represented by one term of Lorentz oscillator, useful information could be obtained.

Microstructure and optical properties of nitrogen doped hydrogenated carbon (a-C:H:N) film deposited by rf plasma enhanced chemical vapor deposition method were studied by AFM, Raman, FTIR and IRE spectrometer. Absorption intensities of the peaks CNH (1600 cm^-1), CN (2200 cm^-1) and NH (3250 cm^-1) in the IR spectra increase with the ratio of flux N₂/CH₄. Raman spectra show the shape of D and G band of a-C:H:N film varies slightly with the increase of N content, which means the main structures of N doped films are still diamondlike carbon films. However Gaussian fit results show that G band widens and the peak shifts to the low wavenumber in Raman spectra is that amorphous C₃N₄ structure formed in the film. AFM topographies and LFM images of a-C:H:N film confirm the amorphous C₃N₄ exists as several ten nanometers particles in the film. IRE spectra analysis results show that refractive index of the film in infrared band (2 - 14 um) slightly decreases from 1.8 to 1.6 with increased nitrogen content in the films.

A novel Y-branch waveguide structure, in which a transitional guide is embedded between an incident channel and output branches, is presented. The transitional guide is used to improve the mode field matching between both waves supported by the incident and output waveguides. Numerical simulations show that this geometry can minimize the junction loss to 0.041 dB at 1310 nm and 0.052 dB at 1550 nm wavelength, respectively. Silica samples based on the design are fabricated by PECVD. Determination shows that the samples exhibit very low junction loss of about 0.08 dB and 0.09 dB at the two wavelengths.

Since the physicochemical properties of cubic BN (c-BN) makes it a very useful material for various industrial and technological applications, cubic boron nitride films have aroused much attention in recent years. In this paper, c-BN films have been prepared by tuned substrate rf magnetron sputtering with different deposition time, which correspond to different growth stages of the BN films. Fourier Transform Infrared Absorption spectroscopy, X-ray Photoelectron Spectroscopy and Atomic Force Microscopy (AFM) have been used to characterize the films. We have found a change of composition and microstructure of the films with different deposition times. AFM images of thicker films showed that there are two BN layers on the substrate and nucleation lines were observed on the lower BN layer of the film. We believe that the thickness difference between the edge and the center of the c-BN sheets of the film, which was also observed in the AFM profile, gives some information about the growth mechanism of c-BN films.

Heteroepitaxial growth of single crystal Silicon Carbide (SiC) films on a novel compound substrate is discussed. Sapphire has successfully been used as substrate material for SOS structure. It shows good isolating properties. Comparing with silicon, its higher melt temperature makes this heteroepitaxial structure more sustainable for later high temperature device fabricate process. GaN and AlN are both wide band semiconductor, they are deposited on sapphire as buffer layer by the means of metal organic chemical vapor deposition to decrease the lattice mismatch between the substrate and the epitaxial layer, and SiC films was grown on buffer layer using APCVD. X-ray diffraction and scanning electron microscope are used to study the polytypes and morphology of the film. Some hexangular etching pits with size of 1 - 5 micrometers are found on the films.

Ellipsometry has been widely used in the measurements of thin film thickness and optical properties. The existence of multiple acceptable models has been confirmed in the interpretation of the measured ellipsometric data, which can degrade the measurement accuracy. How to eliminate this ambiguity is very important. In the present paper, we apply a simulation method to study the existence of multiple acceptable models and to seek the methods to alleviate such kinds of ambiguity. In the simulation study, a simple structure model (silicon dioxide film coated on silicon substrate) is used.