A comprehensive and spectroscopic investigation, including absorption (AB), photoluminescence (PL) and photoreflectance (PR) experiments on the electronic states and their optical transitions in some near-surface and surface quantum well structures of semiconductors are performed and reported here in this paper. The strain relaxation as a function of capping layer, the electronic states on the surface quantum well and the dependence of transition related surface Si (delta) doping on doping concentration.

The origin of vision aids such as eyeglasses, magnifying glasses, telescopes and so forth lies in the distant past and cannot be dated with precision. However, such aids certainly came into use at different times in different cultures. Early portraits and other pictures prove to a certainty, however, that remarkable well-made spectacles were in use by the end of the Middle Ages. Glass was employed for optical lenses from the very beginning, and quality improved continuously with advances in glassmaking and polishing techniques. Starting around 1970, this continuing development received new impetus from the introduction of plastics as a new material for ophthalmic lenses. Rapid progress in plastics chemistry had epoch-making effects on lens technology, and today a wide variety of materials such as CR39, PMMA and polycarbonates, with refractive indices ranging from 1.52 to 1.65, are used for this purpose. Eyeglasses have long been important on other grounds than vision correction; people wear them as adornment, because they are fashionable, to express their personality, and for other reasons. This dramatic history shows no signs of coming to an end, and more innovations are definitely ahead.

The consequences of Ti implantation in silica glasses and Ta₂O₅ layer are studied. It is shown that the optical losses can be low with a variation of the refractive index which can be well controlled. Results on rectangular waveguides and Y junctions are given. Erbium implanted Ta₂O₅ layers exhibit a luminescent behavior both in the green and in the infra-red. The emission diagram of the coating can be controlled with a multilayer structure.

'The Asian Routes Towards the Global Information Society' and 'Towards a Strategic Planning for the Global Information Society' will be the forum themes of 'Asia Telecom 97' and 'Telecom Interactice 97' events respectively, to be held by the International Telecommunication Union (ITU) in order to further telecommunication development around the world. International telecommunications network affects our life by keeping us in touch, bringing us world news and underpinning the global economy. Global tele-economy, global information infrastructure, global information society terms are more and more used to indicate the evolution towards an information- driven world where the access to information, communication and technologies is essential to the economic and social development in every country. Telecommunication industry can strongly contribute to this evolution together with broadcasting and computer industry, and fiber optic communications are expected to continue to grow up and share a relevant part of the total telecom market. In 1995 telecom market shown a 3.8 percent worldwide investment growth reaching a $545 billion value. According to 'Kessler Marketing Intelligence (KMI) Corp.' analysis of fiberoptics and multimedia market the amount of cabled fiber installed in U.S. will be around 11 million fiber-km in 1997 and 15 million fiber-km are predicted in the year 2000. Between 1995 and 1998 the undersea industry is estimated to deal with $13.9 billion as additional undersea cable systems investment in the global telecom network. In China beside satellite telecom stations and digital microwave systems 22 fiber optic backbones have been realized and another 23 systems are expected to be built in the Ninth Five-Year National Plan (1996 to approximately 2000) with a total length of nearly 30,000 sheat-km. The study, Fiber and Fiberoptic Cable Markets in China, recently released by KMI Corp. shows that fiber optic cable installation by MPT and other network operators will grow at an annual average rate of 22 percent from 1.3 million fiber-km in 1995 to 3.5 million fiber-km in 2000. The worldwide components market-cable, transceivers and connectors -- $6.1 billion in 1994, is forecasted to grow and show a 19 percent combined annual growth rate through the year 2000 when is predicted to reach $17.38 billion. Fiber-in-the-loop and widespread use of switched digital services will dominate this scenario being the fiber the best medium for transmitting multimedia services. As long as communication will partially replace transportation, multimedia services will push forward technology for systems and related components not only for higher performances but for lower cost too in order to get the consumers wanting to buy the new services. In the long distance transmission area (trunk network) higher integration of electronic and optoelectronic functions are required for transmitter and receiver in order to allow for higher system speed, moving from 2.5 Gb/s to 5, 10, 40 Gb/s; narrow band wavelength division multiplexing (WDM) filters are required for higher transmission capacity through multiwavelength technique and for optical amplifier. In the access area (distribution network) passive components as splitters, couplers, filters are needed together with optical amplifiers and transceivers for point-to-multipoint optical signal distribution: main issue in this area is the total cost to be paid by the customer for basic and new services. Multimedia services evolution, through fiber to the home and to the desktop approach, will be mainly affected by the availability of technologies suitable for component consistent integration, high yield manufacturing processes and final low cost. In this paper some of the optoelectronic components and related thin film technologies expected to mainly affect the fiber optic transmission evolution, either for long distance telecommunication systems or for subscriber network, are presented.

The synthesis and the characterization of the quantum dot quantum well (QDQW) system are described. The chemical synthesis and substitution method are used to synthesize the three-layered structure compound CdS/CuS/CdS which consists of a core of the CdS nanocrystal and a well of monolayers of CuS capped by monolayers of CdS acting as the outermost shell. The results of inductive coupled plasma mass spectroscopy (ICP-MS) measurement and the absorption spectra confirm the formation of the three-layered system CdS/CuS/CdS.

The luminescent nanocrystal Ge embedded in a-SiO₂ matrix was prepared by thermal oxidation of a-Si_1-xGe_x:H films under conventional conditions. It was found that nc-Ge were formed through the selective oxidation of Si in a-Ge_xSi_1-x:H alloys and precipitation of Ge during oxidation. The average size of nc-Ge changed from 4 nm to 6 nm with the various conditions and Ge contents. Visible photoluminescence with peak energy 2.2 eV was observed from the oxidized samples where the nc-Ge have an average size of 4 nm. In order to control the size distribution of nc-Ge, we used multilayer films of a-Si:H/a-Si_1-xGe_x:H instead of unlayered a-Si_1-xGe_x:H alloy films to prepare nc-Ge embedded in SiO₂ matrix. We found that the size of nc-Ge in perpendicular direction can be well confined by the SiO₂ sublayers simultaneously formed.

Thin films of MoO₃ were prepared by electron beam evaporation technique. The films were deposited onto glass substrates maintained at temperatures in the range 100 - 250 degrees Celsius. The films were characterized by studying their structure, electrical and optical properties. The films formed at 100 degrees Celsius are amorphous with conductivity of about 2.5 X 10^-5 (Omega) ^-1 cm^-1. The effect of deposition temperature on the properties of the films were studied and discussed.

GeSb₂Te₄ phase change thin film was prepared by rf- magnetron sputtering method. Atomic force microscopy (AFM) was used to study the micro-structure of short-wavelength recorded spots. Microarea morphology images show that the recorded domain bulge after laser irradiation. With the increasing of writing pulse width, depression appears in the center of recorded spot. It is demonstrated that AFM is a very useful tool to evaluate the recorded spots and improve the performance of phase change media.

In this paper, we give the equation for the distribution function of electric potential on the metal-metal junction. By perturbation method, we get the distribution function of electric potential when the difference of Fermi energies of these two metals is very small.

Silica antireflective coatings were deposited on KB-7 glass substrates by sol-gel method. The sols were produced via ammonia catalysis tetraethylorthosilicate (TEOS) diluted in ethanol, using different molar ratio, R, of H₂O/TEOS. The influence of amount of water on structure of coatings was investigated by measuring thickness, refractive index, and infrared spectrum of the coatings and BET surface area of the dried gel silica power. The results revealed that the thickness and the refractive index were decreased with the increase of R, whereas the surface area was increased with the increase of R. The infrared spectra indicated that the densification of coating reduced with increase of R.

The combination of micro-optics and integrated optics with microelectronics and micromechanics to create a broader class of micro-opto-electro-mechanical system (MOEMS), various thin films and related technologies such as the bulk and surface micromachining and LIG technology for the elementary structures and devices of MEOMS are discussed.

Functional ceramics have become a news stage with the concept that different kinds of materials, no matter they are organic or inorganic with different functional effects, can be composed together to find a new material by multilayer thin film technologies. In this paper the design of new creative sensors, devices and system is proposed, which is based on: (1) Variation of spontaneous polarization P_s which can be induced or attended to maximum change during phase transformation; (2) Functional thin film materials which can be induced phase transitions by applied stress, temperature or electric field and these exhibit extraordinary piezoelectric, pyroelectric, electrostrictive, electro-optic, etc. and field effect properties in comparison with bulk materials so far existed; (3) Composite of these effects through thin film integrated technology to design new intelligent sensors; (4) Connecting equivalent circuits of functional elements, devices and electronic circuits to design new intelligent systems. As an example, a pyroelectric voltage transformer was introduced. The principle demonstration and experimental results are discussed.

This paper reports the use of hematin Langmuir-Blodgett (LB) films to detect carbon monoxide gas at the room temperature, based on changes in the optical absorption of the films. Hematin LB films were deposited on quartz and glass substrates. For the film deposited on quartz substrate, an increase in the absorption spectra of the film was achieved by exposing the film to carbon monoxide gas. The absorption spectra of the film recover back when the exposing gas was cut off. While for the film deposited on glass substrate, there is no significant change in the spectra due to this gas. Atomic force microscope images were taken for the hematin LB films both on glass and quartz substrates. Both images show different features indicating that the optical respond of the films to the gas depends on the arrangement of molecules on the substrate.

A device based on a mono or multilayers films of a nickel dithiolene-stearyl alcohol complex built with the Langmuir- Blodgett (LB) technique has been investigated as a N₂H₄ gas detector. The films deposited on an aluminum electrode and the changes in the electrical properties of the film when exposed to the N₂H₄ gas were tested. It was found that there still a well response when the device exposed 0.5 ppm N₂H₄ gas at the room temperature, and the changes of electrical conductive of the film is roughly linear with N₂H₄ gas concentration in the lower concentration. The experimental results indicated the response time and recovery time of the sensor are less than 30 seconds.

According to the optical electromagnetic theory, this paper demonstrates that we should not apply the usual simplified theoretical formulas of transparent dielectric (such as glass) to design semiconductor (Si) cell antireflection (AR) films. We must consider the macroscopic optical properties of semiconductor itself. We have deduced a strict formula for wide band three-layer AR coatings on semiconductor (Si) cell. By this formula, we can calculate the 'theoretical reflectance' of solar cells at any film thickness and wavelength. We have screened some type of double-layer film that increased the current gain of space solar cell effectively. For outerspace solar cells, it is necessary to have an 'optical matching system,' which is made up several layers of transparent material: AR coatings of silicon, silicon rubber adhesive and anti-radiation cover glass. For the solar cell with 'optical matching system,' we have also formulated its total reflectance R_t as a function of the reflectance R_m from AR film upon silicon, the index of refraction of cover glass n_g, the index of refraction of silicon rubber adhesive n_j, the transmittance of the upper surface of glass T.R_t has a parabolic type of T.

At present, the biggest problem with diamond coatings as applied to cutting tools is their poor adhesion strength to the substrates. Many substrate treatment as well as growth conditions have been tried to improve the adhesion strength. To evaluate these efforts, utilizing the indentation test is the better way for indentation application. A detailed discussion has been done in this paper.

Large size potassium dihydrogen phosphate (KDP) crystals were coated with a polymethyltriethoxysilane (PMTES) coating for environmental protection. The optical property and environmentally protective ability of coatings are investigated. The coatings have high transmission in the range of 200 to 1100 nm. On the conditions of wavelength 1.054 micrometer and a pulse length 1 ns, the laser damage threshold of the coating is higher than 8.4 J/cm². It is found that the thresholds of the coatings are not obvious change below 80 degrees Celsius and increase with the increasing of the cured temperature. The fogging phenomenon of the KDP crystals coated with PMTES coating has not been observed after more than one year in ambient atmosphere.

This paper discusses some questions about transition radiation effect in film or foil stack, analyses stimulated amplification of optical wave in film or foil stack. In this paper, authors research the possible model about transition radiation effect and ring crystal resonator apply to short wavelength FEL.

The composite films of c and SiO₂ were fabricated by an rf co-sputtering technique and post-annealing treatment, strong PL spectra with a peak energy about 2.22 eV was obtained at room temperature. We investigated the PL spectra dependence on substrate temperature annealing temperature, and sample thickness. Using Raman scattering, IR transmission and XRD measurements, we studied the structures of the composite films. Some results were discussed.

The preparation, measurement and recent experimental results of hybrid and nanocomposite nonlinear optical materials have been reported. The approaches for increasing optical nonlinearity of hybrid and nanocomposite materials are discussed. The optical limiting effects are demonstrated.

The nonlinear-optical properties of poly (p-phenylene- vinylene) (PPV) were studied. The sign and size of the real and imaginary part of (chi) ⁽³) have been measured at 532 nm to be -5.168 multiplied by 10^-9 esu and -1.952 multiplied by 10^-9 esu, respectively by the Z-scan method. The nonlinear refractive index n₂ is of -4.271 multiplied by 10^-9 esu, and all-optical switching in the PPV thin-film waveguide was observed by prism coupling.

The optical nonlinearity of the combination of films of poly(N-vinylcarbazole), abbreviated as PVK, and fullerene C₆₀ has been investigated by third harmonic generation (THG) measurement by using 1064 nm picoseconds (ps) and 790 nm femtosecond (fs) laser beams, respectively. More intense signals were observed from the mixed and multilayer PVK/C₆₀ films than those from pure C₆₀ and PVK films. This signal enhancement was attributed to the complex and carriers produced by the photoinduced charge transfer (CT) process between PVK and C₆₀ molecules in the combination films.

This paper reports the multi-layer optics films processed by magnetron sputtering, and investigated the film thickness monitor and the deposition processes control techniques systematically. And successfully makes the coatings of 0.2% reflection in the visible region.

Proton-exchanged and annealed film in z-cut LiTaO₃ with and without the periodic segment are fabricated. The refractive index, lattice constant, proton concentration, and infrared absorption spectrum of samples are measured by prism coupling, x-ray rocking, SIMS, and spectrometer, respectively. The refractive index increase and the change in lattice constant of the surface layer are noticed during the annealed process.

In this paper, the antireflective coatings consisting of porous silica particles from a silica sol are applied by dip method. The relationships among composition, viscosity and temperature have been studied. The coating homogeneity is opium for the laser wavelengths of 1064 nm, 532 nm and 355 nm. The peak transmission of coated BK-7 glass substrate is higher than 99.5%. The laser induced damage thresholds of the antireflective coatings were range of 7 - 10 J/cm², for 1 ns pulse width and 1064 nm wavelength. These damage thresholds were suitable for our national ICF program. It is noted that the optical homogeneity of coating and the viscosity of coating sol were strongly influenced by the temperatures in the duration of sol ripening.

Two kinds of voltage-tunable-color triple layer organic light emitting diodes consisted of styryltriphenyamine SA and 8- hydroxyquinoline aluminum chalet Alq³ or laser dye DCM doped Alq³ as emission layers and oxadizole PBD as carrier confinement layer have been fabricated. They emit both from SA and Alq³ or DCM doped Alq³ and their emission color dependent on the applied voltage. The ratios of blue from SA and green or orange-red from Alq³ or Alq³:DCM increased with the increasing of applied voltage. Brightness current characteristic has been invest9iEnergy models have been assumed and the EL behaviors are explained.

Artificial magnetic superlattices composed of successive ferromagnetic and paramagnetic layers have received much attention in recent years due to their scientific and technological relevance. While the strength of the exchange coupling and the oscillation period depend on the details of the Fermi surfaces involved, the overall features appear universal. More complex couplings are observed for magnetic superlattices with chromium spacer layer. This is due to the intrinsic spin density wave of Cr. Extensive synchrotron and neutron scattering experiments have now unraveled the Neel- state of thin Cr layers and proximity effects between Fe and Cr, elucidating the mutual interdependence of Cr spin structure and Fe exchange coupling. In Co/Cr superlattices the structural mismatch between hcp Co and bcc Cr adds another complexity, which affects strongly the magnetic anisotropy. Both, the current status and understanding of the exchange coupling in Fe/Cr(001) and Co/Cr(001) superlattices is briefly reviewed here.

The transformation from stimulated to spontaneous emissions at 77K is performed in Zn_0.8Cd_0.2Se-ZnSe strained layer superlattice (SLS) with Fabry-Perot cavity. It is found that the lasing oscillation modes disappear and the stimulated emission is transformed into the amplified spontaneous emission owing to the phase space filling effect of exciton states under higher excitation density.

Surface treatment effects on microscopic morphology of Si(111) and (100) surfaces have been investigated by atomic force microscope (AFM). Well-ordered atomic steps and flat terraces have been clearly observed on the Si(111) surfaces treated in 40% NH₄F solution. Then, SiO₂ films were deposited on these atomically flat substrates at 300 degrees Celsius by photo-CVD method. Interface state density of the Si/SiO₂ structure with this flat surface is smaller than that of the substrate with disordered surface. On the other hand, in the case of Si(100) wafers, atomically flat structures have not been observed in the surfaces treated by 1% HF, 40% BHF, and HF/H₂O₂ solutions, and a lot of small and random unevennesses have been observed on each surface. Si/SiO₂ interface state density decreases with decreasing average roughness of Si surface.

In this paper, the general formula was found for one- dimensional computation of GaAs-Ga_1-xAl_xAs superlattice or quantum well. The formula can be used to calculate donor binding energy in external field using the effective-mass approximation. The effect of superlattice structure and different external fields were expressed as potential energy item V vector (r) in Hamiltonian. The results were of universal significance in a certain sense and application prospects for developing new material.

In our experiments, we found that the adhesion of multilayer film system containing 'soft film' material of ZnS and metal Ag was evidently superior to that of multilayer film system containing 'hard film' material of SiO₂ and metal Ag. Through the compared research on the interface adhesion of two film systems, we theoretically explained this 'contradictory' phenomenon. The key is the difference of interface adhesive force. The adhesive force between the Ag-ZnS interface is affected by the action of both ionic bond force of interface transition layer and image effect force. This force is bigger than the van der wall's force which is the primary source of adhesive force between the Ag-SiO₂ interface. From this research, a method can provided to resolve the moisture and other problem in the thin film techniques.

The formation of iron oxide films and their roles in determining the dry wear properties of low alloy steel couples are described. Essentially, alpha-Fe₂O₃, haematites (Fe₃O₄), wustite (FeO) and oxide mixtures were the predominant compositions found in four regions of mild oxidational wear. The oxides were initially formed during subsequent rubbing and removal of material from the surfaces where oxidation, nucleation and agglomeration processes took place, followed by plastic deformation and work-hardening of underlying layers which supported the films. These films were found to be protective against wear; stable film of Fe₃O₄ reduced wear rate down to as low as 10^-13 m³m^-1, while loose particles of FeO maintained wear rate greater than 10^-12 m³m^-1. The wear protective nature of (alpha) -Fe₂O₃ and mixed films were found to lie between these extreme limits. Hence, the role of oxide films, in particular Fe₃O₄, is very significant in minimizing the wear and friction of alloy steel.

Photoreflectance (PR) spectroscopy system is combined with molecular beam epitaxy (MBE) to accomplish in-situ PR measuring of the Si surface (delta) doping on GaAs (001) with different concentrations at different temperatures. The features observed on the high-energy side of the fundamental gap are attributed to transitions involving electronic subbands in the half V-shaped potential well. We find that the Si (delta) -doping-related spectral structure first shifts to high energy side with the doping concentration increasing, then almost stop shifting with the doping concentration higher than 2.4 X 10¹⁴ cm^-2 when temperature increases, at certain doping concentration the Si (delta) - doping-related transition shifts toward low energy side. The dependence of the transition on doping concentration is well explained by using a simple theoretical model.

A new passivation film: evaporated CdTe/ZnS combination film was grown on HgCdTe and the interface was characterized by capacitance-voltage (CV) characteristics of metal-insulator- semiconductor (MIS) test structures. Under proper processing conditions, the interface electrical parameters are: density of fixed charge approximately -4.0 X 10¹⁰ cm^-2, density of slow state approximately 5.1 X 10¹⁰cm^-2, density of fast interface state approximately 2.7 X 10¹¹cm^-2eV^-1, and the time stability is good. These results show CdTe/ZnS double layer film is suitable for passivation of HgCdTe infrared detectors. We have also investigated single layer ZnS and anodic oxide/CdTe/ZnS triple layer film and found that the time stability of ZnS isn't good, and there exists too high density of fixed positive charge at the triple layer film//HgCdTe interface.

To enhance the adhesion of diamond film on WC-Co substrate, interface of TiC and SiC by sputtering technique were introduced between them. The film structure and surface morphology have been checked by x-ray diffraction, Raman spectroscopy and SEM. The adhesion between both coating and substrate have been evaluated by cutting test. In addition, the vertical tensile test has been carried out to measure the adhesion strength, which indicated that the introduce of the interface layer played important effect for improvement of the film adhesion strength.

A technique of ultrasonic surface pretreatment in diamond powder slurry to enhance diamond nucleation has been developed. Under appropriate pretreatment and growth conditions, diamond grain densities of approximately 10¹⁰ cm^-2 have been obtained on fused silica substrates. The synthesis technique of ultrathin diamond film on fused silica substrates by a hot filament chemical vapor deposition was studied, and high quality ultrathin diamond films with smooth surface were obtained. The optical transmittance of the film with a thickness of approximately 0.3 micrometer on fused silica substrate reached as high as 68% at wavelength of 800 nm.

YBCO thin film with strontium titanate buffer layer has been made by using unbalanced magnetron sputtering (UMS). It has been shown experimentally that resputtering effect, usually takes place in balanced magnetron sputtering and glow discharge sputtering is suppressed. It turns out that the critical temperature as well as the critical current is improved.

In-situ laser deposition was used to fabricate YBa₂Cu₃O_7-x superconducting films on YSZ substrates. The surface topography of YBa₂Cu₃O_7-x thin films has been studied with both atomic force microscopy (AFM) and scanning tunneling microscopy (STM). A stepped surface is clearly observed on the mounds with a single step edge the originates from a screw dislocation at the center of the mound and moves out to the edge in a spiral fashion. The experimental result show that the spiral growth structure is an intrinsic character of superconductor films. The existence or absence of the spiral growth structure and the quality of the spiral structures may have significant implications for properties of the high temperature superconducting thin films. The new visual details may lead to improvements of YBCO films.

In this paper, the homogeneous and transparent Nb₂O₅(x)-(1-x)Fe₂O₃(x equals 0, 0.6, 0.7, 0.8, 0.9, 1.0) films were prepared by sol-gel dip-coating method using metal alkoxide [Nb(OC₂H₅)₅] and Fe(NO₃) 9H₂O as sol-gel precursors. Based on the reflectance spectra, the refractive indexes and thickness of the films were deduced. The electrochemical investigation of Li⁺ ions storage process in Nb₂O₅-Fe₂O₃ films has been made in a Pt/LiClO₄-PC(1M)/Nb₂O₅-Fe₂O₃ITO cell between -2.0 V and 1.0 V potential range vs SCE. The total electric charge inserted and extracted during a cycle has been determined by the cyclic voltammetries. The electric charge transition ability is mainly influenced by the composition and heat treatment temperature. In pure Nb₂O₅ system, an orthorhombic crystalline phase presents after heat treated at 560 degrees Celsius for an hour.

Diamondlike thin films were prepared by irradiation of high purity graphite with a high power density( 1.178 x I 09 Watt I cm2 ) laser (XeCI 308 nm) in the vacuum ( I x 10-s Torr) . Raman spectra show the thin film with the properties of diamond, the scatter peak is in round 1330 cm-1 . The IR spectra show the thin film containing C-H bonds, and the ratio ofH to C is about 45%. The resistivity and optical energy gap of the thin film are 1.89 x 106 .0 .cm and 1.55 e. V, respectively. Keywords: Pulsed Laser deposition, Diamondlike thin film, Raman spectra.

Blue-green and blue stimulated emission under photopumping in Zn_0.8Cd_0.2Se-ZnSe and ZnSe-ZnS multiple quantum wells (MQWs) on (100) GaAs substrate grown by atmospheric pressure metalorganic chemical vapor deposition (AP-MOCVD) have been investigated, respectively. For the Zn_0.8Cd_0.2Se-ZnSe MQWs, the stimulated emission of the sample with different cavity length is observed at 77K, two groups of stimulated emission lines observed are attributed to n equals 1 heavy- hole (hh) and light-hole (lh) exciton transition, respectively, and it is noticed that the sample with the shorter Fabry-Perot cavity length has the larger threshold excitation and more mode spacing. For the ZnSe-ZnS MQWs, the blue stimulated emission is observed and attributed to the exciton-exciton interactions.

Plastic flows of a large lattice-mismatch InSb epilayer on GaAs substrate grown by metalorganic chemical vapor deposition (MOCVD) were first observed by scanning electron acoustic microscopy (SEAM), and crystalline state of the buried subsurfaces was discussed. From the SEAM images in two different positions a macroscopical heterogenous distribution of large compression stress fields was studied. It was a very important result to observe and study the plastic flows by SEAM uniquely imaging mechanism.

The lead zirconate titanate (PZT) thin films, with Zr/Ti ratio of 52/48 have been synthesized by the sol-gel method. Perovskite barium titanate (BaTiO₃) nanopowders have been introduced in the precursor sols as seeds, to induce the perovskite phase formation at low temperatures. Their effect on the phase formation process, during the crystallization of PZT thin film was studied. Pure perovskite PZT thin films were obtained at 550 degrees Celsius and 600 degrees Celsius, when 5 mole% and 1 mole% perovskite BT crystalline seeds were used, respectively.

The purpose of the study is to design a single wafer vertical organo-metallic vapor phase epitaxy (OMVPE) reactor which gives a uniform deposition around the symmetry axis. The vertical reactor under the consideration consist of a diffuser and a system of coaxial cylinders to laminarize the flow which may lead to a uniform deposition without rotating the susceptor. The simulation shows that for a susceptor with a radius of 2.5 cm, a uniformity can be achieved in a region of a radius of 2 cm within 1% for certain operating condition. The result is compared with the experimental measurement of TiO₂ deposition from TTIP.

Porous alumina membranes prepared by a sol-gel process, using aluminum isopropylate as precursors, were characterized by XRD, SEM, TEM, TG and DTA. It showed the mean pore diameter and the membrane thickness could reach tens of nanometers (nm), 3 micron (micrometer) respectively. The conditions of hydrolysis of aluminum isopropylate, processing sol to gel and the influences of heating on forming alumina membrane have been studied.

TiO₂ nanoparticle thin films are fabricated via sol-gel process followed by dip and spin coating technique, using Ti(OC₄H₉)₄ as raw material. A complexing agent is used in order to form a stable sol. Experiments show that the colloidal particles in the sols are relatively large under basic catalyst conditions, while under acidic conditions, the colloidal particles are only about several nanometers. The properties and structures of the films are studied. The films are normally homogenous and crack-free. TEM shows that the films are composed of nanoparticles with a certain porosity. Under the thermal treatment of 80 degrees Celsius, the porosity and thickness of the film decrease while the refractive index increases from the original 1.70 to the final 1.89. When the temperature of the thermal treatment goes up, the size of the nanoparticles increases and crystallization occurs.

Phosphorous-doped nano-crystalline silicon films have been prepared by plasma enhanced chemical vapor deposition (PECVD) system. Detailed results on dark electrical conductivity, Raman spectra, infrared absorption spectra, hydrogen content are presented. The doped sample's grain size and its volume fraction is little related to doped concentration, whereas, the room-temperature conductivity of doped samples changed as doped concentration increased from 10^-4 - 10^-1; its value can reach to maximum value of 3.57 (Omega) ^-1 cm^-1 when PH₃/SiH₄ equals 2 X 10^-2. The conductivity activation energy of doped sample is smaller than that of undoped nc-Si:H film and hydrogen content is about 10 - 15%, also smaller than that of nc-Si:H film.

MoO₃ films allow high intercalation rate, but deintercalation is difficult to perform. It is the reason the MoO₃ film has lower response time for use as electrochromic display materials. The effect of additive on the electrochromic property of MoO₃ thin films produced by sol-gel method has been studied. The pure and TiO₂-doped MoO₃ thin films were characterized optically and electrochemically in LiClO₄-propylene carbonate solutions. The experimental results showed that the additive of TiO₂ had improved remarkably the cyclic stability and reversibility of the MoO₃ film electrochromic electrode.

Sol-gel processing of acid-catalyzed tetrabutoxytitanate, 3- glycidyl propyl trimethoxisilane and monomeric methyl methacrylate to produce titania-silica sol-gel optical coatings and matrix materials has been systematically studied. The coatings were deposited by dip-coating technique on glass substrates from a polymeric solutions, pseudo-ternary phase diagram were used to outline the regions of stability of the Ti(OC₄H₉)₄-C₂H₅OH-H₂O-HAC and Ti(OC₄H₉)₄-GPTMS-C₂H₅OH-H₂O-HAC system respectively. It was found that the stability of the system depend on the compositions, especially the molar ratio of [H₂O]/[Ti(OC₄H₉)₄]. The use of GPTMS allows a thicker coatings than is possible with the sol- gel films prepared from non-organically modified alkoxides.

Uncooled infrared detectors consisting of thin film pyroelectric oxide heterostructures have been fabricated. Pb(Zr,Ti)O₃ (PZT) and (Sr,Ba)Nb₂O₆ (BSN) thin films were integrated to YBa₂Cu₃O_7-x (YBCO) films on yttria-stabilized zirconia (YSZ)-buffered Si(100) and on LaAlO₃(100) substrates by the pulsed laser deposition technique. The YBCO thin films are used both as IR reflector- conductive electrodes and as atomic templates for PZT and BSN epitaxial growth, but not necessarily for their superconducting properties. The crystalline properties and photoresponse of the oxide thin film heterostructure infrared detectors were characterized from room temperature up to the phase transition temperatures of PZT and BSN. Detectivity values of approximately 10⁸ cmHz^1/2/W at room temperature have been obtained for simple heterostructure device configurations. The tunable phase transition temperature, dielectric constant and pyroelectric properties of the oxide allow for the development of an infrared detector with operation at temperatures higher than room temperature.

Recently, reduction of production costs with maintaining high reliability is required for wider applications of capacitors. Ni-electrode multilayer ceramic capacitors (MLCCs) of BaTiO₃-based dielectrics and AgPd-electrode MLCCs of relaxor materials were developed to meet the requirements. Thinner dielectriclayers, miniaturization, and high capacitance are also major requirements for MLCCs. In these circumstances, much effort has been paid in order to achieve higher reliability. Ni-electrode MLCCs are promising way to satisfy the requirements of high capacitance, low cost, and high reliability. Major problems about the reliability were mechanical fracture, degradation of insulation resistance, and capacitance aging. These phenomena are strongly affected by both chemical composition and producing process.

Photoluminescence (PL), time-resolved photoluminescence (TRPL) and photoconductivity (PC) measurements were used to investigate the excitation transfer (ET) and charge transfer (CT) processes occurring in the poly(N- vinylcarbazole)(PVK)/C₆₀ and poly(2-methoxy-5-(4-bromo- butoxy) phenylene vinylene)(MBB-PPV)/C₆₀ combination films. The transferring excitation energy from the excited states of polymers to C₆₀, PL intensity quenching and lifetime shortening of polymers were observed from PL and TRPL measurement while great enhancement in PC measurement of multilayer polymer/C₆₀ film was also obtained.

In this study, two different processes, with and without rapid thermal annealing (RTA), have been compared for the Al-Si- Cu/TiN/Ti multilayer contact on n+ diffusions. A series of wafer level reliability (WLR) measurement performed on a test structure with two 1.08 X 1.08 micrometer² contacts on n+ diffusion. The results show that RTA can increase contact electromigration (EM) lifetime dramatically. The XRD, AES and TEM analysis indicate that this improvement is attributed to oxygen stuffing in TiN, phase change of TiN and TiSi₂ formation at the interface of Ti and Si.

Tin selenide thin films have been prepared onto glass substrates at a temperature 240 degrees Celsius and fixed film thickness by means of a solid state reaction process at pressure about 10^-5 mbar. Low level antimony doping was maintained at a concentration 1.8%. The dark current- voltage measurements have been performed on the sandwiched structures of Al-SnSe-Al and Al-SnSe:Sb-Al at temperatures in the range 143 - 300 K, and the results showed a ln J varies direct as V^1/2 dependence which was indicative of the Poole-Frenkel effect. It was found that, the calculated field-lowering coefficients, (beta) _p for the latter samples (3.71 - 4.81 X 10^-5 eV m^1/2 V^-1/2) were higher than the predicted value (2.18 X 10^-5 eV m^1/2 V^-1/2) by a factor of 1.71 - 2.21. These were further confirmed by the linear dependence of the graphs's slope and inverse of temperature. The results were explained in terms of lowering potential barrier by the interaction of electron with applied electric field.

Details are given of an experimental study of field electron emission phenomenon associated with two types of carbon containing thin film, i.e. non-doped fullerene C₆₀ and amorphous diamond films. A transparent anode imaging technique was used to record the spatial distribution of individual emission sites and the total emission current-voltage (I-V) characteristic of the films. This study has revealed that stable electron emission can be obtained from both types of film at fields as low as 3 - 6 MV/m. A quasi-direct tunneling model is proposed to explain the observed emission.

SrBi₂Ta₂O₉ thin films are prepared on Pt sheets by the laser ablation method using an ArF excimer laser below 560 degrees Celsius. Crystallographic properties of the film are characterized as parameters of substrate temperature, O₂ or N₂O gas pressure and laser repetition frequency. SrBi₂Ta₂O₉ thin films are oriented preferentially to (105) on Pt sheets. The depth profile of x-ray photoelectron spectra (XPS) reveals a homogeneous composition and XPS signals of Bi suggest oxygen deficiency of the film on Pt sheet. The films deposited on Pt sheet consist of spherical grains of about 100 nm diameter. D-E hysteresis loops is observed at SrBi₂Ta₂O₉ thin film deposited on Pt sheet. The remanent polarization was 2.5 (mu) C/cm² and coercive force was 34 kV/cm.

Tin selenide (SnSe) thin films have been prepared by encapsulated selenization technique. The Sn/Se stacked films were deposited by vacuum evaporation and annealed at 200 degrees Celsius for 3 hours to form a stoichiometric SnSe compound. Optical absorption measurements were made on the as- prepared sample using spectrophotometer in the range from UV to visible region (200 - 900 nm). The absorption coefficient, (alpha) was found to be greater than 10⁵ cm^-1 that suggested the occurrence of either indirect allowed or direct forbidden optical transition. A further investigations on the (ahv)^1/2 and (ahv)^2/3 plots against photon energy have been carried out and the resulting optical bandgap obtained from indirect allowed transitions were 0.95 eV for 40.5 nm sample and reduced to 0.79 eV for 125 nm sample thickness. In the case of direct forbidden transition, the energy gaps were between 1.20 - 1.08 nm. The results also showed that the band gap decreased with increasing sample thickness.

The diode consisting of nano-silicon quantum dots embedded in an amorphous silicon matrix is fabricated. The discontinuous staircases on its I-V curves are observed. There are two distinct regimes on I-V curves of diode: (1) the sequential tunneling regime, where current increases monotonously with increased negative bias; (2) the resonant tunneling regime, where the current increases dramatically with increased negative bias and three quantum staircases appear. The qualitative explanation of this physical phenomenon is proposed.

Sol-gel dip coating method was adopted to prepare Rhodamine-6G doped SiO₂-TiO₂ thin films. Effects of MTMS/TEOS ratio on the crack of the thin films during drying stage were studied. The cracking was greatly decreased with the increase of MTMS/TEOS ratio. Crack free thin films were obtained for the samples with MTMS/TEOS greater than 0.75. The optical absorption and fluorescence spectra of the thin films were recorded. The refractive index increases linearly with the increase of TiO₂ content (20, 40, 60 mol%). The third order nonlinear susceptibility of the Rhodamine-6G doped SiO₂-TiO₂ thin films is (chi) ⁽³) approximately equals 10^-9 esu measured by the generate four wave mixing technique.

The dispersion characteristics of magnetic spatial solitons on an antiferromagnetic slab have been studied in this paper. The guided spatial soliton is on the plane interface between an antiferromagnetic slab and a semi-infinite linear dielectric. The distinguishing feature of the soliton is the existence of its frequency passband(s) and stopband(s) that can be switched into each other by varying the power.

A new electro-optic polymer film DMACB-PEK-c has been prepared. The refractive indices of the film at 0.63- micrometer, n_t and n_n, are determined by the quasi- waveguide m-line method. The results of measurement and calculation are: n_t equals 1.6573 plus or minus 0.0017, n_n equals 1.6278 plus or minus 0.0019.

Bi₂Sr₂Ca₁Cu₂O_7-x(BSCCO) superconducting films were deposited on Si substrates with buffer layers of Y- stabilized ZrO₂ films (YSZ) by magnetic sputtering. The critical temperature (Tc) of BSCCO film on YSZ/Si was 82 K. The microstructure of BSCCO/YSZ/Si was studied by scanning electronic microscope (SEM) and atom force microscope (AFM), the growing model of spiral nucleation was verified. Fractal images were found in the micrographs, and their growth mechanism was presented.

We have studied the passivation of superconducting YBa₂Cu₃O₇ (YBCO) films by diamond-like carbon (DLC) films using ion implantation and laser irradiation techniques. The experiment suggests that the surface layers of the YBCO films are covered by a DLC structure and critical temperature (Tc) measurements have confirmed the absence of any significant degradation after these treatments. The DLC layer successfully protects the superconducting films from environmental effect.

RuO₂ thin films have been grown by the pulsed laser deposition (PLD) method. It was shown that the RuO₂ thin film were (110) oriented and in-plane ordered (epitaxially grown). The electrical and optical properties of the RuO₂ thin film have been measured. When grown at 700 degrees Celsius, the films exhibited resistivities as low as 39 (mu) (Omega) (DOT) cm at room temperature. The real and imaginary parts of the dielectric constant and complex refractive index for RuO₂ thin films were estimated in the photon energy range from 1.5 to 4.5 eV by spectroscopic ellipsometry measurements. A transition from the valence band to the conduction band was observed for RuO₂ thin films near 2.7 eV and the dependence of the refractive index on the deposition temperature was also observed.

In this paper, a cyanine film has been prepared by spin- coating process on the pre-grooved polycarbonate substrate. The transmission, reflection and absorption spectra of the film were measured. The complex refractive index n, k of the film was calculated. Under the recording condition specified by CD-R Orange Book, the carrier to noise ratio (CNR) of the single dye layer disk are greater than 47 dB at traveling rate of 1.4 m/s, 2.8 m/s, and 5.6 m/s. The estimated lifetime of the CD-R using this dye film as the recording medium reaches up to 10 years under normal using condition.

Atomically regulated unit-cell by unit-cell homoepitaxial SrTiO₃ (STO) and heteroepitaxial BaTiO₃ (BTO) films were fabricated on STO (100) substrates by laser molecular beam epitaxy. The fine streak patterns and more than 1000 cycles undamping intensity oscillation were obtained by in situ reflection high-energy electron diffraction (RHEED). The films were examined by atomic force microscopy (AFM), X-ray diffraction (XRD), x-ray photoelectron spectrometer (XPS), (phi) scan, and the cross-section high-resolution TEM. The root-mean-square surface roughness of the films is about 0.1 nm. The FWHM of the XRD (omega) -rocking curve for the (200) diffraction peak of BTO film is 0.235 degrees. The results indicate that the films have a high degree of c-oriented epitaxial crystalline structure and the surfaces of films are atomically smooth.

In spite of the advantage of droplet reduction in the pulsed laser deposition (PLD) process, eclipse PLD method has some drawbacks that activated growth species are also shielded by the shadow mask, and deposition rate decreases in low ambient pressure condition. In this study, we proposed new composite shadow mask method named 'eclipse angel PLD method' to overcome this problem. We directly observed the emitting plume propagating through the ring-mask structure and reaching the substrate by the ultra fast camera, and confirmed growth rate enhancement of YBa₂Cu₃O_x thin films in low ambient oxygen pressure region. Also, did we the effects of Ar addition when are of favor to improve the film qualities of Bi-layered crystals.

This paper introduces the materials and structure as well as the forming method of ultrathin films for ion-preventative feedback. The characteristics and measuring results are given. In the meantime, preliminary analysis and discussion are carried out.

Hg_1-xCd_xTe films were grown by a modified meltetch liquid phase epitaxial (LPE) technique which includes both substrate and epilayer etchback steps. The crystal quality of epilayer has been investigated by means of transmission electron microscope (TEM), scanning electron microscope (SEM), and double crystal x-ray rock curve (XRD). It has been found that adequate meltetch of the substrate at the beginning of LPE provides a fresh and flat surface for epitaxial growth, while epilayer meltetch at the end of LPE may prevent spurious and melt sticking.

Lead magnesium niobate titanate, 0.6Pb(Mg_1/3Nb_2/3)O₃-0.4PbTiO₃ (PMN-PT) thin films have been prepared on MgO crystal and Pt sheet at low temperatures of 450 - 600 degrees Celsius by laser ablation method. PMN-PT thin films have preferential orientation of a-axis on MgO(100) and have (100), (200) and (110) orientations on Pt. Surface morphology of PMN-PT films on Pt has the spherical grain of size 100 - 200 nm. Dielectric constants of 0.6PMN-0.4PT thin films is about 940 at 1 MHz and room temperature.

Zr-rich lead zirconate titanate (PZT) thin films with a thickness of 1 micrometer were successfully grown on (111)PLT/Pt(111)/Ti(101)/SiO₂/Si(100) substrates by an rf planar magnetron sputtering equipment using a multi-target which consisted of PbO and metal titanium pellets on a zirconium metal plate. The optimum sputtering conditions were a gas content of Ar:O₂ equals 8:2 Sccm, gas pressure of 6 X 10^-3 Torr, rf power of 100 W and substrate temperatures of 630 - 650 degrees Celsius. The composition of the films could be controlled by adjusting the area ratio of PbO/Zr/Ti. The crystal structures of films were sensitive to the substrate temperature. The pyroelectric current, relative dielectric constant, remanent polarization and coercive field of the PZT films were measured. These electrical properties depending on the ratio of Zr/Ti in the films are described. The phase transition of low temperature to high temperature rhombohedral ferroelectric phases in as-grown PZT films is also reported. Zr-rich PZT films sputtered on (111)PLT/Pt/Ti/SiO₂/Si substrate possess desirable properties for potential applications to pyroelectric devices.

To investigate the influence of solution concentration on controlled crystallization of calcium phosphate, controlled crystallization in the presence of stearic acid monolayer from solutions of hydroxyapatite with different [Ca²⁺] have been studied by SEM, TEM with ED, IR, XRD. When [Ca²⁺] is 0.4 mM, octacalcium phosphate (OCP) which is a thermodynamically undersaturated phase in this condition precipitates due to the 'concentration effect' of charged headgroup -COO^- of stearic monolayer to Ca²⁺ in the solution; while solution is supersaturated in which [Ca²⁺] is 4 mM, the first precipitates phase is hydroxyapatite (HAP) with (0001) parallel to the surface of stearic monolayer. Subsequent growth results in oriented OCP crystals, and all the crystals show a white semi- globular characters; while [Ca²⁺] is up to 5 mM, the increasing of mineralization rate results to the rapid nucleation of HAP into some core-like structure and the later growth of platelet-like OCP as the 'shell.' Nucleation of DCPD between OCP showing a flower-like structure also found at LB film/solution interface. The mechanism of influence of concentration was discussed.

In this paper we introduce a method of measuring thin layer thickness using a sandwich structure of the In_0.43Ga_0.57As_0.15P_0.85/In_0.13Ga_0.87As_0.75P_0.25/In_0.43Ga_0.57As_0.15P_0.85 DH with the interference fringes in rocking curve by x-ray double-crystal diffraction.

Vanadium pentoxide films were prepared by evaporation followed by annealing post-treatment in O₂ atmosphere. Lithium was inserted electrochemically from an electrolyde into vanadium pentoxide films so that Li_xV₂O₅ was formed. The structure of the post-treated samples was determined by XRD and infrared reflectance was measured by FTIR for as-grown and lithiated films, respectively. The experimental results have shown that V₂O₅ thin films have some infrared absorption peaks located at 982, 824, 527 and 504 cm^-1, and the infrared vibration bands corresponding to the peaks have a good agreement with the analysis by Abello et al. for polycrystalline V₂O₅, and there is an obvious influence of lithium insertion on the infrared vibration properties which may be reconciled with the lattice change such as expansion and contraction.

A new method for replicating microstructure elements is presented. The principle and technological process of the method are introduced. For one polymer, deep binary relief grating on quartz substrate is replicated by using this new method and the relief-transfer efficiency and transparency are measured. The results show that the replicas are of high fidelity of profile and are suitable for practical applications.

Two kinds of two dimensional electrons in same surface have been found in Hg_1-xCd_xTe (x equals 0.214) photoconductive detectors from studies of the shubnikov-de Haas (SdH) oscillation. It has been found that the number of electrons in each kind is about constant from 1.5 K to 55 K by SdH measurements. A model considered two kinds of surface electrons is proposed to fit the temperature dependence of the resistivity. The electrical parameters obtained by this model agree well with the experiment and the results given by SdH measurements. This paper offers a simple and effective model to investigate the bulk and surface electrical properties for a two-terminal device.

The preparation method and short-wavelength optical storage properties of Ge-Te alloy phase change thin film are reported. The film was prepared by rf-sputtering technology. The deposited films were amorphous. The crystallization temperature was 190 degrees Celsius. The optical spectrum measurements showed that the reflectivity of the crystalline state film was rather high -- about 50% at 780 nm, which may be suitable for CD-E storage medium. A static optical recording tester with a focused Argon laser beam (514.5 nm) irradiating on the films was used to evaluate the optical storage performance of the films. The results showed that a rather large reflectivity contrast (larger than 15%) can be obtained at low power beam.

Cyclotron resonance (CR) of two-dimensional electron gases (2DEG) in GaAs/AlGaAs heterojunction was studied by the gate voltage ratio spectrum measurement technique. The oscillation behaviors of the intensity of the CR peaks, the electron effective mass, scattering time and mobility obtained by fitting the CR line shape with the magnetic field due to the resonant subband Landau level coupling (RSLC) were observed. Several intersubband energies with high quantum index were measured by this RSLC method at different gate voltage. The results are in good agreement with the self-consistent calculations including the depolarization shift and the exciton effect correction.

The influence of buffer layer on the growth of GaN epilayer was investigated. Five matching orientations were identified when GaN was directly grown on the sapphire (0001) plane. The use of low-temperature buffer layer significantly improved the epitaxial film quality and the surface morphology. The optimal thickness of buffer layer was about 18 nm - 20 nm in the present growth condition.

This paper summarizes the technical characteristics and performance of our newly purchased VG V80H MBE system. Our research work on thin film semiconductor laser materials growth on this system has also been presented here, with some discussion on beam flux stability and growth uniformity et al.

Manufacture of AlGaAs/GaAs QDs by visible light lithography and etching is accomplished in this paper, and the size distribution is studied by smaill-spotted PL. The broadening of PL peaks which is caused by the fluctuation of quantum well is studied.

ZnTe_xSe_1-x epilayers with composition x equals 0.005, 0.02 and 0.16 have been grown by low pressure-metal organic chemical vapor deposition (LP-MOCVD) method. Two bands (blue S1 and green S2) were observed in the ZnTe_xSe_1-x epilayer with composition x equals 0.005 at room temperature (RT). With increasing composition x greater than 0.02, the S1 band disappeared and the S2 band was the main emission in photoluminescence (PL) spectra. The origin of the S1 and S2 bands was attributed to excitons trapped at Te₁ and Te_n (n greater than or equal to 2) cluster.

At high excitation intensity the photoluminescence (PL) spectra of ZnCdSe/ZnSe multiple quantum wells were studied, which showed strong excitonic emission and a broad emission band at low energy side. The dependence of the broad emission band on excitation intensity shoed obviously that the broad emission band is related to impurity. In time resolved luminescence spectra, with increasing the delay times (ns), the broad emission band shifts to low energy side and full width at half maximum decreased, which showed the typical characteristic of donor-acceptor pairs (DAP) emission. And then, the reason that the excitonic emission peak and the DAP band decay with same speed was discussed and it was attributed to the free carriers relax effect.

The band edge nonlinear absorption in ZnTe/CdZnTe multiple quantum wells (MQWs) is studied at room temperature. It is found that the exciton absorption peak tends to saturate, broaden and the absorption edge shift to lower energy side with increasing of pump intensities. The optical bistability in ZnTe/CdZnTe MQWs optical bistable device is investigated on transmission at room temperature. The research result indicates that the threshold and contrast ratio for the optical bistability in ZnTe/CdZnTe MQWs optical bistable device are about 292.5 kW/cm² and 3:1, respectively.

A long-wavelength 128 by 1 GaAs/AlGaAs multiple quantum wells (MQWs) infrared detector (IRD) array is presented. A good photo-current responsibility R_p equals 2.02 X 10⁶V/W is obtained with the cut-off wavelength being (lambda) _c equals 8.6 micrometer and as a result, we obtain a good remanent heat image of a room-temperature subject.

Characters of PbGeTe single layer is likely affected by various factors. The adhesion of PbGeTe single layer and PbGeTe/ZnS multilayer deposited on Si substrate by PVD method is investigated by means of x-ray diffraction. The correlation of layer growing rate and the preferred orientation of Si wafer is studied by the grind angle to measure the thickness method. The particle structure of films on various surface situations is studied by the image analysis. It has been noticed, that the adhesion of PbGeTe single layer is stronger in strength than that of the PbTe single layer, which shows little correlation with the preferred orientation of the substrate. The adhesive strength of the films can be improved by inserting thin layer of Ge or oxide layer. We have found that the layer growing rate varies with the preferred orientation of the substrate, we have also noticed that the particle structure of the films can be affected by the roughness of the substrate and the polishing method. Finally, the refractive index of Pb1-xGexTe(x equals 0.08) single layer was calculated.

The LPE growth characteristics of ultra-thin quaternary InGaAsP alloy on GaAs substrate with different sliding speeds and various graphite growth cells has been described. The properties of grown layer are charactered by SEM, photoluminescence spectrum and x-ray diffractometer. Ten to fifty nm InGaAsP layer can be easily obtained and the FWHM of PL spectrum is about 14 mev at 10 K.

Excitonic optical bistability with nanosecond switching time in ZnSe-ZnS multiple quantum wells (MQWs) with a Fabry-Perot (FP) cavity is investigated at room temperature. The research result indicates that the threshold and contrast ratio for the optical bistability in ZnSe-ZnS MQWs with a FP cavity are about 0.2 MW/cm² and 6:1, respectively. On the basis of the room temperature excitonic absorption spectra obtained here, we attribute the major nonlinear mechanism for the optical bistability to the excitonic saturating absorption due to phase space filling of excitonic states and excitonic band broadening.

Cu_1-xCO_x granular films with x equals 19, 27, 43, and 45 achieved by sputtering with different argon gas pressure are studied by the magnetic and magnetoresistance measurement. With the increase of the sputter argon gas pressure P, the remanence and coercive force increases, but the MR ratio has a maximum value around P equals 1.5 Pa, confirming that a proper size of Co grains and a suitable concentration are required for the large MR. And for Co/Cu/Co sandwiches, we found there was an MR ration oscillation as Cu layer thickness was varied.

Hydrogenated amorphous silicon carbide (a-Si_1-xC_x:H) films were fabricated in the plasma-enhanced chemical vapor deposition system by using silane (SiH₄) and two kind of carbon sources, methane (CH₄) and xylene (C₈H₁₀), respectively. The optical band gap of methane-made a-Si_{1- x}C_x:H was varied from 1.9 eV to 2.6 eV while that of xylene-made a-Si_1-xC_x:H could be extended to 3.5 eV. Fourier transform infrared spectra demonstrated the existence of aromatic ring in xylene-made a-Si_1-xC_x:H, which is much different from the carbon configuration of methane-made a-Si_1-xC_x:H. Visible light emission at room temperature was observed from xylene-made a-Si_1-xC_x:H films. The photoluminescence peak shifted from 630 nm (1.97 eV) to 450 nm (2.75 eV) when the optical band gap of samples increased from 2.3 eV to 3.5 eV. KrF pulse laser with wavelength of 248 nm was used to crystallize these two kinds of films at room temperature. For both samples the conductivities can reach 10^-5S/cm and are enhanced by over four orders of magnitude.

A new sol-gel route for zirconia coating is now reported. Zirconia coatings consisting of zirconia particles were prepared from inorganic precursor (ZrOCl₂8H₂O) by a simple alcothermal process instead of the complicated hydrothermal method published by others. The coatings were applied by dip method. The zirconia coating structures and optical properties were investigated. The dependencies of coating thickness and refractive index on heat temperature were studied. It is noted that the abrasion resistance of coating is rapidly increased as cured temperature. The laser induced damage thresholds of zirconia coatings were range of 4 - 5 J/cm², for 1 ns pulse width and 1064 nm wavelength. The relevant chemistry is discussed.

The hydrogenated nano-crystalline silicon (nc-Si:H) films are prepared using conventional plasma enhanced chemical-vapor- deposition (PECVD) system and oxidized by plasma and high- temperature treatment which all doped oxygen into nc-Si:H film. The contents of hydrogen and oxygen, the infrared absorption spectra, photo-luminescence (PL) spectra are measured. The PL peak wavelengths blue-shift from 695 nm to 660 nm at 77 K, but there are still no obvious visible PL at room-temperature through oxidized post-processing. The bonded forms of oxygen in nc-Si:H are changed with different oxidized way and their influence on PL spectra are also investigated.

For the granular type of Co-Ag (1.8 nm)/Ag multilayers with the Co contents of 22, 45, and 65 at%, the magneto-resistance ratio ((Delta) R/R) has a maximum found with respect to the AG spacer layer thickness. It is found that with increasing Co content the (Delta) R/R peak shifts towards thicker AG layers. For the Co-Ag/Ag multilayers with low Co contents, (Delta) R/R increases monotonically with increasing magnetic layer thickness, but has a maximum near the magnetic layer thickness of 2.2 nm for the sample having a higher Co content. The peak is thought as a result of the antiferromagnetic (AFM) coupling between the nearest Co clusters in neighboring magnetic layers. In the high field region, the magnetization and the square root of (Delta) R/R vary as a linear function of the reciprocal applied field for all multilayers. In the low field range, they are proportional to the applied field for samples with thin magnetic layers.

The growth mechanism of diamond films from low pressure vapor phase synthesis cannot be illustrated with classical thermodynamic theory. Up to now, a lot of growth methods were reported, but the growth mechanism was not so clear. In this paper, a variety of growth methods and growth conditions were summarized, and some tries to illustrate the growth mechanism of diamond film from the consideration of quantum mechanics bond theory were carried out. Particularly, some effects of atomic H and SP³ bond on the growth mechanism of diamond film were illustrated.

The measuring conditions of the thickness of thin films with grazing incident x-ray is explained, and interferential principle and method to measure the thickness of thin films by grazing incident x-ray are discussed and analyzed in the paper. The periodic thickness of the multilayer optical thin films is measured with double-crystal diffractometer at a very small grazing incident angle, the result is satisfactory and measured values is in good agreement with designed values.

Worldwide the incorporation of ferroelectric thin films in the future generations of DRAMs and in memory devices in which the remnant polarization is used to achieve a non volatile data storage (FeRAMs) is under intense investigation. Currently all the leading companies in the memory chip business are running programs to integrate the new materials into their semiconductor fabrication. On a smaller scale, but also expected as rapidly growing in the near future are thin film pyroelectric detector arrays for the presence and motion detection of persons in a wide range of applications. Currently three materials are favored for these three applications: For the storage capacitor of the DRAMs (Ba,Sr)TiO₃, for the FeRAMs SrBi₂Ta₂O₉ and for the pyroelectric detector arrays lead based perovskites like PbTiO₃ and Pb(Zr, Ti)O₃(PZT). The focus of this paper is thin film pyroelectric detector arrays on silicon substrates using PZT thin films as pyroelectric material. A planar multi-target approach was used to deposit PZT films on Pt electrodes at very low substrate temperatures of about 450 degrees Celsius. These films have been used for fabricating a two dimensional 11 by 6 pixel pyroelectric detector array for motion detection. The array pixels with a sensitive area of 280 by 280 micrometer² have a noise equivalent power NEP of less than 0.7 nW at 1 Hz.