Dr. Alexandru Hening Profile

Dr. Alexandru Hening

Senior Researcher at Sscpac

SPIE Involvement:

Author

Publications (7)

Proceedings Article | 13 June 2023 Presentation + Paper

A rapid prototyping approach towards cryogenic photoluminescence spectroscopy of monolayer transition metal dichalcogenides and their heterostructures

Carlos Torres, B. Melvin Pascoguin, James Adleman, Brad Liu, Richard Ordonez, Cody Hayashi, Alexandru Hening, Kathryn Liotta, Teresa Emery-Adleman

Proceedings Volume 12517, 1251703 (2023) https://doi.org/10.1117/12.2663927

KEYWORDS: Monolayers, Chemical vapor deposition, Sapphire, Heterojunctions, Photoluminescence, Excitons, Spectroscopy

Read Abstract +

Cryogenic photoluminescence spectroscopy is a versatile tool to locally probe the defects in diverse material platforms as well as to observe modifications of the underlying electronic band structure in novel two-dimensional quantum materials such as the monolayer transition metal dichalcogenides (TMDs) (e.g. MoS₂, WS₂, WSe₂, and MoSe₂) and their heterostructures. These monolayer TMDs feature direct bandgaps and excitons with high binding energies due to quantum confinement which are conducive towards optoelectronic applications. We present our latest results on the characterization of monolayer TMDs and heterostructures based on monolayer TMDs using our newly developed fiber optic-based cryogenic photoluminescence setup in the Quantum Engineered Nano Devices Laboratory (QENDL) at the Naval Information Warfare Center Pacific (NIWC Pacific) towards their future implementation in quantum applications. Specifically, we investigate the temperature dependence of photoluminescence (PL) for Chemical Vapor Deposition (CVD) and Molecular Beam Epitaxy (MBE) grown monolayer TMDs on sapphire (0001) substrates; CVD monolayer WS₂-MoS₂ heterostructure on sapphire (0001) substrate; CVD monolayer WSe₂-MoSe₂ heterostructure on sapphire (0001) substrate; CVD monolayer MoS₂ on CVD monolayer hexagonal boron nitride (hBN) on SiO₂-silicon substrate; and CVD monolayer WS₂ on CVD monolayer hBN on sapphire (0001) substrate. We observed a significant temperature dependent direct bandgap red shift in CVD and MBE monolayer MoSe₂ on sapphire (0001), MBE monolayer WS₂ on sapphire (0001), and MBE monolayer WSe₂ on sapphire (0001) substrate. We estimated the exciton binding energy in MBE monolayer WSe₂ on sapphire (0001) by fitting the peak PL intensity values to the Arrhenius equation. Furthermore, we observed quite different temperature dependence of PL spectra from the monolayer CVD WS₂-MoS₂ heterostructure on sapphire (0001) substrate, which suggests the existence of spatial inhomogeneity across the sample. We also observed a temperature dependent PL peak red shift in both monolayer CVD WS₂-MoS₂ heterostructure on sapphire (0001) and monolayer CVD WSe₂-MoSe₂ heterostructure on sapphire (0001) substrate. Finally, we observed significant variability in the PL peak wavelength dependence on temperature for the transferred monolayer CVD MoS₂ on transferred monolayer CVD hBN on SiO2-silicon substrate as well as for the transferred monolayer CVD WS₂ on transferred monolayer CVD hBN on sapphire (0001) substrate.

Proceedings Article | 22 May 2017 Paper

Deployable wavelength optimizer for multi-laser sensing and communication undersea

Burton Neuner, Alexandru Hening, B. Melvin Pascoguin, Brian Dick, Martin Miller, Nghia Tran, Michael Pfetsch

Proceedings Volume 10186, 1018607 (2017) https://doi.org/10.1117/12.2264945

KEYWORDS: Oceanography, Retroreflectors, Polarization, In situ remote sensing, Ocean optics, Meteorology, Optical communications, Free space optics, Algorithm development, Optical design, Telecommunications, Free space, Laser communications

Read Abstract +

Proceedings Article | 7 October 2014 Paper

Applications of laser-induced filaments for optical communication links

Alexandru Hening, David Wayne, Mike Lovern, Mark Lasher

Proceedings Volume 9224, 92240J (2014) https://doi.org/10.1117/12.2063559

KEYWORDS: Atmospheric propagation, Laser optics, Plasma, Fiber optic gyroscopes, Laser applications, Free space optics, Atmospheric plasma, Clouds, Atmospheric physics, Optical communications

Read Abstract +

Proceedings Article | 3 October 2014 Paper

Evolution of laser-induced plasma in solvent aerosols

Alexandru Hening, Ronald Wroblewski, Robert George, Scott McGirr

Proceedings Volume 9224, 92240I (2014) https://doi.org/10.1117/12.2062305

KEYWORDS: Plasma, Aerosols, Atmospheric propagation, Cameras, Atmospheric plasma, Plasma generation, Pulsed laser operation, Infrared imaging, Femtosecond phenomena, Visible radiation

Read Abstract +

Proceedings Article | 29 June 2001 Paper

Quantum communication and single-photon technologies

Anders Karlsson, Mohamed Bourennane, D. Ljunggren, J. Ciscar, M. Mathes, Alexandru Hening

Proceedings Volume 4430, (2001) https://doi.org/10.1117/12.432873

KEYWORDS: Photons, Quantum communications, Quantum cryptography, Quantum information, Single photon, Quantum efficiency, Avalanche photodetectors, Sensors, Cryptography, Photon counting

Read Abstract +

Proceedings Article | 2 July 1998 Paper

UV laser radiosensitivity of normal and tumoral chromatin

Liliana Radu, Ion Mihailescu, V. Preoteasa, Irina Radulescu, Doina Gostian, Alexandru Hening, S. Radu

Proceedings Volume 3405, (1998) https://doi.org/10.1117/12.312827

KEYWORDS: Liver, Luminescence, Tumors, Ultraviolet radiation, Energy transfer, Energy efficiency, Absorption, Proteins, Excimer lasers, Statistical analysis

Read Abstract +

Proceedings Article | 2 July 1998 Paper

Growth of polycrystalline hydroxyapatite thin films by pulsed laser deposition and subsequent heat treatment in air

V. Nelea, Cornel Ghica, C. Martin, Alexandru Hening, Ion Mihailescu, Leona Nistor, Valentin Teodorescu, Rodica Alexandrescu, J. Werckmann, Eniko Gyorgy, Gheorghe Marin

Proceedings Volume 3405, (1998) https://doi.org/10.1117/12.312755

KEYWORDS: Thin films, Pulsed laser deposition, Plasma, Transmission electron microscopy, Bone, Diffraction, Crystals, Photomicroscopy, Absorption, Biocompatible materials

Read Abstract +

Showing 5 of 7 publications

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years