Dr. Paul Hongen Shen Profile

Dr. Paul Hongen Shen

Senior Scientist at DEVCOM Army Research Lab

SPIE Involvement:

Author

Publications (56)

Proceedings Article | 11 June 2013 Paper

Time-resolved photoluminescence study of carrier recombination and transport in type-II superlattice infrared detector materials

Blair Connelly, Grace Metcalfe, Hongen Shen, Michael Wraback

Proceedings Volume 8704, 87040V (2013) https://doi.org/10.1117/12.2016202

KEYWORDS: Superlattices, Luminescence, Mid-IR, Gallium, Long wavelength infrared, Continuous wave operation, Infrared detectors, Temperature metrology, Antimony, Infrared radiation

Read Abstract +

Proceedings Article | 15 October 2012 Paper

Temperature-dependent minority carrier lifetimes of InAs/InAs[sub]1-x[/sub]Sb[sub]x[/sub] type-II superlattices

E. Steenbergen, B. Connelly, G. Metcalfe, H. Shen, M. Wraback, D. Lubyshev, Y. Qiu, J. Fastenau, A. W. Liu, S. Elhamri, O. Cellek, Y.-H. Zhang

Proceedings Volume 8512, 85120L (2012) https://doi.org/10.1117/12.930949

KEYWORDS: Stereolithography, Superlattices, Temperature metrology, Sensors, Long wavelength infrared, Astatine, Quantum efficiency, Infrared detectors, Electrons, Semiconductors

Read Abstract +

Proceedings Article | 25 May 2012 Paper

III-V nitride semiconductors for solar hydrogen production

Vijay Parameshwaran, Chad Gallinat, Ryan Enck, Anand Sampath, Paul Shen, Tevye Kuykendall, Shaul Aloni, Michael Wraback, Bruce Clemens

Proceedings Volume 8377, 83770B (2012) https://doi.org/10.1117/12.925200

KEYWORDS: Semiconductors, Indium gallium nitride, Electrodes, Silicon, Gallium nitride, Photons, Gallium, Hydrogen, Absorption, Semiconductor materials

Read Abstract +

Proceedings Article | 16 September 2011 Paper

Study of recombination mechanisms limiting the performance of Sb-based III-V type II superlattices for infrared detectors

Blair Connelly, Grace Metcalfe, Hongen Shen, Michael Wraback

Proceedings Volume 8155, 81550L (2011) https://doi.org/10.1117/12.893964

KEYWORDS: Doping, Superlattices, Luminescence, Interfaces, Gallium antimonide, Long wavelength infrared, Sensors, Indium arsenide, Temperature metrology, Infrared radiation

Read Abstract +

Proceedings Article | 22 February 2008 Paper

Effect of interface polarization charge on the performance of nitride semiconductor light emitting diodes

Hongen Shen, Meredith Reed, Eric Readinger, Michael Wraback

Proceedings Volume 6889, 688905 (2008) https://doi.org/10.1117/12.773871

KEYWORDS: Polarization, Light emitting diodes, Heterojunctions, Interfaces, Quantum wells, Bismuth, Semiconductors, Electron holes, Gallium, Field effect transistors

Read Abstract +

Proceedings Article | 8 February 2007 Paper

Enhanced luminescence from AlxGa1-xN/AlyGa1-yN quantum wells grown by gas source molecular beam epitaxy with ammonia

Sergey Nikishin, Boris Borisov, Gregory Garrett, Wendy Sarney, Anand Sampath, Hongen Shen, Michael Wraback, Mark Holtz

Proceedings Volume 6473, 647306 (2007) https://doi.org/10.1117/12.701394

KEYWORDS: Gallium, Aluminum, Quantum wells, Luminescence, Quantum dots, Aluminum nitride, Molecular beam epitaxy, Transmission electron microscopy, Light emitting diodes, Picosecond phenomena

Read Abstract +

Proceedings Article | 2 February 2007 Paper

Optimization of nanoscale phenomena in AlGaN for improved UV emitters

M. Wraback, G. Garrett, A. Sampath, H. Shen

Proceedings Volume 6479, 64791H (2007) https://doi.org/10.1117/12.699181

KEYWORDS: Excitons, Picosecond phenomena, Luminescence, Ultraviolet radiation, Light emitting diodes, Internal quantum efficiency, Gallium nitride, Temperature metrology, Diffusion, Aluminum

Read Abstract +

Proceedings Article | 13 October 2006 Paper

Device challenges for biodetection

M. Wraback, M. Reed, G. Garrett, A. Sampath, H. Shen

Proceedings Volume 6398, 63980W (2006) https://doi.org/10.1117/12.693124

KEYWORDS: Gallium nitride, Picosecond phenomena, Light emitting diodes, Luminescence, Avalanche photodetectors, Ultraviolet radiation, Semiconductors, Sensors, Ultraviolet light emitting diodes, Avalanche photodiodes

Read Abstract +

Proceedings Article | 20 May 2005 Paper

Light emitting diode arrays for HWIL sensor testing

Naresh Das, P. Shen, George Simonis, John Gomes, Kim Olver

Proceedings Volume 5785, (2005) https://doi.org/10.1117/12.602326

KEYWORDS: Light emitting diodes, Sensors, Black bodies, Resistors, Gallium antimonide, Mid-IR, Body temperature, Liquids, Nitrogen, Projection systems

Read Abstract +

Proceedings Article | 25 March 2005 Paper

Fundamental studies of nanoscale phenomena in ultraviolet photonic materials and devices

Michael Wraback, Gregory Garrett, Anand Sampath, Charles Collins, Sergey Rudin, H. Shen

Proceedings Volume 5732, (2005) https://doi.org/10.1117/12.588010

KEYWORDS: Picosecond phenomena, Aluminum, Gallium, Gallium nitride, Ultraviolet radiation, Electron transport, Sapphire, Light emitting diodes, Semiconductors, Luminescence

Read Abstract +

Proceedings Article | 29 December 2004 Paper

Make light, not heat: toward higher efficiency nitride semiconductor ultraviolet optical sources

Michael Wraback, Gregory Garrett, Anand Sampath, Charles Collins, Paul Shen

Proceedings Volume 5617, (2004) https://doi.org/10.1117/12.581202

KEYWORDS: Picosecond phenomena, Gallium nitride, Aluminum, Aluminum nitride, Luminescence, Indium, Gallium, Quantum wells, Semiconductors, Ultraviolet radiation

Read Abstract +

We have used subpicosecond time-resolved photoluminescence (TRPL) downconversion techniques to study the interplay of carrier localization and radiative and nonradiative processes in the active regions of light emitting III-nitride semiconductor ultraviolet optical sources, with the goal of identifying potential approaches that will lead to higher radiative efficiency. Comparison of TRPL in (In)AlGaN multiple quantum well active regions indicate that for addition of only 0.01 In content the PL decay time in an InAlGaN MQW is more than double that in an AlGaN MQW designed to emit at the same wavelength (360 nm), thus indicating the importance of indium for improvement of material quality, most likely through the suppression of point defects. This result is further underscored by TRPL data on 320 nm InAlGaN MQW active regions, which exhibit longer PL lifetimes than expected for growth on GaN templates with dislocation densities in the mid-10⁸cm^-2 range. While the PL lifetimes in these InAlGaN MQWs improve for growth on lower dislocation density HVPE bulk GaN substrates, a similar phenomenon is not observed for deposition on nearly dislocation-free bulk AlN substrates, suggesting that defect generation in the MQWs associated with lattice mismatch or AlN surface preparation may play an important role. The pump intensity dependence of the time zero signal and the TRPL decays in the MQWs implies that internal electric field-induced recombination through the barriers and interface states plays an important role in the radiative efficiency of quantum well active regions for c-axis oriented materials and devices. The effect of these internal electric fields can be mitigated through the use of nonpolar MQWs. The combination of more intense time-integrated PL spectra and shorter PL lifetimes with decreasing well width in GaN/AlGaN MQWs grown on a-plane LEO GaN for low pump intensity suggests that the radiative lifetime becomes shorter due to the accompanying increase in exciton binding energy and oscillator strength at smaller well width in these high quality samples. Finally, it is demonstrated that compositional fluctuations in AlGaN active regions grown by plasma-assisted MBE can be employed to create spatial localization that enhances the luminescence efficiency and PL lifetime (300-400 ps) despite high defect density (>10¹⁰cm^-2) by inhibiting movement of carriers to nonradiative sites. Significant enhancement of this phenomenon has been obtained in a DH LED structure grown on a lower defect density (mid-10⁹cm^-2) AlGaN template, with PL lifetime increased by nearly a factor of two, corresponding to a defect density in the mid-10⁷ cm^-2 range, and only a 3.3 times drop in PL intensity when the temperature is raised from 12 K to room temperature, suggesting up to ~ 30% internal quantum efficiency.

Proceedings Article | 29 December 2004 Paper

AlGaN materials for semiconductor sensors and emitters in 200- to 365-nm range

Alexander Usikov, Elizaveta Shapvalova, Yuri Melnik, Vladimir Ivantsov, Vladimir Dmitriev, Charles Collins, Anand Sampath, Gregory Garrett, Paul Shen, Michael Wraback

Proceedings Volume 5617, (2004) https://doi.org/10.1117/12.578452

KEYWORDS: Gallium nitride, Aluminum nitride, Silicon carbide, Doping, Gallium, Sapphire, Magnesium, Zinc, Ultraviolet radiation, Silicon

Read Abstract +

Proceedings Article | 13 September 2004 Paper

Characterization of InGaAs self-mixing detectors for chirp amplitude-modulated ladar (CAML)

Keith Aliberti, William Ruff, Hongen Shen, Peter Newman, Mark Giza, Wendy Sarney, Michael Stead, John Dammann, Rishabh Mehandru, Fan Ren

Proceedings Volume 5412, (2004) https://doi.org/10.1117/12.542072

KEYWORDS: Sensors, LIDAR, Indium gallium arsenide, Receivers, Modulation, Signal detection, Semiconductor lasers, Target detection, Gallium arsenide, Photodetectors

Read Abstract +

Proceedings Article | 18 June 2004 Paper

Analysis of InGaAs metal-semiconductor-metal OE mixers

Paul Shen, Keith Aliberti, Barry Stann, Peter Newman, Rishabh Mehandru, Fan Ren

Proceedings Volume 5349, (2004) https://doi.org/10.1117/12.527487

KEYWORDS: Photodetectors, Indium gallium arsenide, Electrons, Optoelectronics, Diodes, Circuit switching, Electroluminescence, Modulation, Absorption, Electrodes

Read Abstract +

Proceedings Article | 21 August 2003 Paper

Mixing characteristics of InAlAs/InGaAs metal-semiconductor-metal optoelectronic mixers

Keith Aliberti, Hongen Shen, Barry Stann, Rishabh Mehandru, Fan Ren

Proceedings Volume 5086, (2003) https://doi.org/10.1117/12.512030

KEYWORDS: Indium gallium arsenide, Photodetectors, Optoelectronics, LIDAR, Sensors, Circuit switching, Diodes, Gallium arsenide, Absorption, Electroluminescence

Read Abstract +

Proceedings Article | 21 August 2003 Paper

Performance of an FM/cw prototype ladar using a 32-element linear self-mixing detector array

William Ruff, Keith Aliberti, John Dammann, Mark Giza, Paul Shen, Barry Stann

Proceedings Volume 5086, (2003) https://doi.org/10.1117/12.485873

KEYWORDS: LIDAR, Sensors, Receivers, Modulation, Interference (communication), Signal to noise ratio, Signal detection, Signal processing, Prototyping, Optical amplifiers

Read Abstract +

Proceedings Article | 25 July 2003 Paper

Electrical-thermal-optical simulation of GaAs/AlGaAs oxide-confined VCSELs

Vladimir Smagley, Min Lu, Gennady Smolyakov, Petr Eliseev, Marek Osinski, Brian Riely, Hongen Shen, George Simonis

Proceedings Volume 4986, (2003) https://doi.org/10.1117/12.482324

KEYWORDS: Gallium, Vertical cavity surface emitting lasers, Aluminum, Refractive index, Oxides, Gallium arsenide, 3D modeling, Quantum wells, Instrument modeling, Active optics

Read Abstract +

Proceedings Article | 25 July 2003 Paper

Multiphysics modeling of intracavity-contacted VCSELs

Brian Riely, J. Jiang Liu, Hongen Shen, Gerard Dang, Wayne Chang, Y. Jiang, Z. Sikorski, T. Czyszanowski, Andrzej Przekwas

Proceedings Volume 4986, (2003) https://doi.org/10.1117/12.482321

KEYWORDS: Vertical cavity surface emitting lasers, Instrument modeling, Data modeling, Performance modeling, Semiconductor lasers, Doping, 3D modeling, Physics, Computer aided design, Quantum wells

Read Abstract +

Proceedings Article | 25 July 2003 Paper

Finite difference analysis of thermal characteristics of CW operation 850-nm lateral current injection and implant-apertured VCSEL with flip-chip bond design

Rishabh Mehandru, Gerard Dang, Kelly Ip, Suku Kim, Fan Ren, Stephen Pearton, William Hobson, John Lopata, Wayne Chang, H. Shen

Proceedings Volume 4986, (2003) https://doi.org/10.1117/12.480855

KEYWORDS: Vertical cavity surface emitting lasers, Continuous wave operation, Resistance, Mirrors, Optical switching, Optical fibers, Semiconductors, Analytical research, Chemical analysis, Signal processing

Read Abstract +

Proceedings Article | 25 July 2003 Paper

Effect of carrier screening on InGaAs MSM detector

Hongen Shen, Keith Aliberti, Gerard Dang, Michael Wraback

Proceedings Volume 4986, (2003) https://doi.org/10.1117/12.480857

KEYWORDS: Indium gallium arsenide, Photodetectors, Sensors, Diodes, Solids, Picosecond phenomena, Energy efficiency, Semiconductors, Gallium arsenide, Absorption

Read Abstract +

Proceedings Article | 30 May 2003 Paper

Femtosecond optical studies of carrier localization and recombination in III-nitride semiconductors

Michael Wraback, G. Garrett, A. Sampath, C. Collins, Hongen Shen

Proceedings Volume 4992, (2003) https://doi.org/10.1117/12.475715

KEYWORDS: Gallium nitride, Aluminum, Picosecond phenomena, Reflectivity, Luminescence, Semiconductors, Gallium, Sapphire, Ultrafast phenomena, Absorption

Read Abstract +

We have used femtosecond time-resolved reflectivity and luminescence downconversion techniques to study carrier relaxation, localization, and recombination in III-nitride semiconductors. Intensity dependent, frequency degenerate pump-probe reflectivity measurements employing near-bandgap excitation provide information about initial carrier localization, subsequent ultrafast heat generation due to nonradiative recombination or trapping in states deep in the bandgap, and photoinduced absorption associated with excitation of carriers from localized states to the bands. These phenomena and their experimental signatures are illustrated for Al_0.25Ga_0.75N and Al_0.4Ga_0.6N samples, in which the photoinduced change in reflectivity ΔR decays faster with decreasing intensity and changes sign, with faster decays for a given intensity in the higher Al content sample. This behavior suggests that in these cases the dynamics are governed by trapping at localized states associated with alloy fluctuations that become deeper and more numerous as the Al content increases. Within this context the sign change and subsequent temporal evolution of ΔR may be indicative of ultrafast heat generation and/or photoinduced absorption, depending upon A1 content. Nondegenerate pump-probe reflectivity experiments designed to separate the electronic contributions of the ΔR decays from the slower thermal components by using a sub-bandgap probe are used to measure carrier lifetime in GaN. Comparison with data obtained from frequency degenerate experiment sunder identical excitation conditions employing a near bandgap probe indicate that in the frequency degenerate case the decay times in ΔR are inflated due to the presence of an additional long-lived component with the same sign as the electronic contribution. The sign and power dependence of this slow decay suggest that it may be associated with screening of a surface electric field by carriers trapped in deep states. In addition, a new technique is presented that employs luminescence downconversion using an ultrashort gating pulse to enable the characterization of UV light emission from III-nitride semiconductors with subpicosecond temporal resolution. This technique also allows one to measure PL rise times and fast components of multiple decays in the subsequent time evolution of the PL intensity. Comparison of luminescence emission intensity and lifetime in GaN and AlGaN with ~0.1 Al content grown homoepitaxially on GaN templates with the same quantities measured in heteroepitaxial layers grown on sapphire indicate significant improvement in the homoepitaxial layers due to reduction in defect density. Fast (<15 ps) initial decays in the AlGaN are attributed to localization in shallow traps associated with alloy fluctuations, with subsequent recombination through gap states.

Proceedings Article | 5 August 2002 Paper

Rectification in metal-semiconductor-metal detectors used as optoelectronic mixers

Paul Shen, Keith Aliberti, Michael Stead, William Ruff, Barry Stann

Proceedings Volume 4721, (2002) https://doi.org/10.1117/12.478855

KEYWORDS: Sensors, Picosecond phenomena, Diodes, Signal detection, Solids, LIDAR, Gallium arsenide, Optoelectronics, Electrodes, Signal generators

Read Abstract +

Proceedings Article | 29 July 2002 Paper

Characterization of a 32-element linear self-mixing detector array for an FM/cw ladar

William Ruff, Keith Aliberti, Mark Giza, Paul Shen, Barry Stann, Michael Stead

Proceedings Volume 4723, (2002) https://doi.org/10.1117/12.476415

KEYWORDS: Sensors, LIDAR, Modulation, Detector arrays, Signal detection, Photography, Receivers, Semiconductor lasers, Optical amplifiers, Signal processing

Read Abstract +

Proceedings Article | 12 June 2002 Paper

Use of photodetectors for the measurement of carrier velocities in wide-bandgap semiconductors

Michael Wraback, Hongen Shen, Sergey Rudin

Proceedings Volume 4646, (2002) https://doi.org/10.1117/12.470507

KEYWORDS: Diodes, Gallium nitride, Electron transport, Picosecond phenomena, Heterojunctions, Monte Carlo methods, Velocity measurements, Resistance, Photodetectors, Femtosecond phenomena

Read Abstract +

We present an optically-detected time-of-flight technique with femtosecond resolution that monitors the change in the electroabsorption due to charge transport in a p-i-n diode, and show how it may be used to determine the electron transit time, velocity-field characteristic, and transient electron velocity overshoot in GaN at room temperature. In a GaN homojunction p-i-n diode, the peak electron velocity of 1.9x10⁷ cm/s , corresponding to a transit time of ~2.5 ps across the 0.53 micrometers depletion region, is attained at ~ 225 kV/cm. The steady-state velocity-field characteristic is in qualitative agreement with theoretical calculations. A measurement of the high field transient electron velocity overshoot was also performed using a semi-transparent p-contact AlGaN/GaN heterojunction p-i-n diode. Transient electron velocity overshoot is observed at fields as low as ~100 kV/cm, with the peak transient electron velocity becoming larger with increasing electric field until a maximum of 7.25x10⁷ cm/s is observed within the first 200 fs after photoexcitation at a field of 320 kV/cm. At higher fields, the measurement of the peak velocity is limited by the 80 fs duration of the pulses, but the increase in transit time with increasing field suggests the onset of negative differential resistance. Theoretical Monte Carlo calculations incorporating a GaN full-zone band structure show that although the peak steady-state velocity occurs at ~200 kV/cm, the ensuing negative differential resistance region of the velocity-field curve is not initially associated with intervalley transfer, as the majority of electrons do not attain sufficient energy to effect this transfer until they are subjected to much higher fields (>325kV/cm). Insight into this behavior can be gleaned from the band nonparabolicity deduced from the constant energy surfaces in the (Gamma) valley, which shows that the effective mass in the c-direction can be viewed as becoming larger at high k-values. This larger effective mass may play a role in velocity overshoot by reducing the velocity and momentum relaxation time at high k-values in the (Gamma) valley. Theoretical calculations employing a semiclassical transport model in the collisionless regime confirm the importance of this nonparabolicity for the determination of the temporal shape of the transient velocity overshoot curves.

Proceedings Article | 12 June 2002 Paper

Modeling the optoelectronic mixing effect in metal-semiconductor-metal detectors

Keith Aliberti, Hongen Shen, Michael Stead, William Ruff, Barry Stann

Proceedings Volume 4646, (2002) https://doi.org/10.1117/12.470508

KEYWORDS: Sensors, Optoelectronics, Electrodes, Gallium arsenide, Diodes, LIDAR, Modulation, Photodetectors, Signal detection, Solids

Read Abstract +

Proceedings Article | 21 May 2002 Paper

Femtosecond studies of fundamental materials issues in III-nitride ultraviolet photodetectors

Michael Wraback, Hongen Shen

Proceedings Volume 4650, (2002) https://doi.org/10.1117/12.467652

KEYWORDS: Aluminum, Gallium, Absorption, Gallium nitride, Picosecond phenomena, Photodetectors, Reflectivity, Carrier dynamics, Ultraviolet radiation, Femtosecond phenomena

Read Abstract +

We have used femtosecond time-resolved optical techniques to study fundamental materials issues in III-nitride semiconductors relevant to the realization of high quality ultraviolet photodetectors. Intensity dependent pump-probe reflectivity and transmission measurements have been employed in the investigation of carrier dynamics in AlGaN alloys with Al content ranging from ~0.15 to 0.4. For the Al_0.15Ga_0.85N sample, the intensity dependence of the (Delta) R decay suggests that at high intensity the shallow traps are saturated and ultrafast nonradiative recombination dominates the carrier dynamics. For the Al_0.25Ga_.75N and Al_0.4Ga_0.6N samples (Delta) R decays faster with decreasing intensity and changes sign. Moreover, the decays are faster for a given in tensity in the higher Al content sample. This behavior suggests that in these cases the dynamics are governed by trapping at localized states that become deeper and more numerous as the Al content increases. Within this context the sign change in (Delta) R in A;_0.4Ga_0.6N may be indicative of the onset of photoinduced absorption associated with the excitation of carriers from the localized states to the bands, which has also been observed in time-resolved transmission measurements. This localization may be associated with alloy fluctuations that broaden the absorption edge of the material and degrade the long-wavelength performance of photodetectors. In addition, time-resolved electroabsorption measurements on an AlGaN/GaN heterojunction p-i-n photodiode have been used to study the transient electron velocity overshoot for transport in the c-direction in wurzite GaN. The velocity overshoot is observed at fields well below the field at which the calculated peak steady-state velocity occurs, and it increases with electric field up to ~320 kV/cm, at which field a peak velocity of 7.25x10⁷ cm/s is attained within the first 200 fs after photoexcitation. These results are consistent with theoretical Monte Carlo calculations incorporating a GaN full-zone band structure, which show that because of band nonparabolicity in the (Gamma) valley the majority of electrons do not attain sufficient energy to effect intervalley transfer until they are subjected to higher fields (>325kV/cm). This behavior may have important implications for avalanche photodiodes, for which electrons are promoted to higher lying bands for participating in the avalanche process.

Proceedings Article | 19 September 2001 Paper

Research progess on scannerless ladar systems using a laser diode transmitter and FM/cw radar principles

Barry Stann, Ahmed Abou-Auf, Scott Frankel, Mark Giza, William Potter, William Ruff, Paul Shen, Deborah Simon, Michael Stead, Zoltan Sztankay, Luke Lester

Proceedings Volume 4377, (2001) https://doi.org/10.1117/12.440102

KEYWORDS: LIDAR, Sensors, Modulation, Signal processing, Semiconductor lasers, Imaging systems, Staring arrays, Target detection, Signal detection, Amplifiers

Read Abstract +

Proceedings Article | 30 May 2001 Paper

High-bandwidth multichannel optoelectronic interconnects for parallel data and image transmission and processing

J. Jiang Liu, Zaven Kalayjian, Brian Riely, Brian Gollsneider, William Lawler, Wayne Chang, Paul Shen, Monica Taysing-Lara, Peter Newman, George Simonis

Proceedings Volume 4292, (2001) https://doi.org/10.1117/12.428038

KEYWORDS: Vertical cavity surface emitting lasers, Photodetectors, Receivers, Image transmission, Image processing, Optical interconnects, Transmitters, Signal processing, Optoelectronics, Sensors

Read Abstract +

Proceedings Article | 23 April 2001 Paper

Measurement of carrier transport and dynamics in wide bandgap semiconductors using femtosecond pump-probe techniques

Michael Wraback, Hongen Shen, M. Wood, John Carrano, Charles Collins, Ting Li, Joe Campbell, Christopher Eiting, Damien Lambert, U. Chowdhury, M. Wong, Russell Dupuis, Matthew Schurman, Ian Ferguson

Proceedings Volume 4280, (2001) https://doi.org/10.1117/12.424741

KEYWORDS: Diodes, Electron transport, Gallium nitride, Picosecond phenomena, Femtosecond phenomena, Heterojunctions, Absorption, Interfaces, Scattering, Information operations

Read Abstract +

Proceedings Article | 15 December 2000 Paper

Passive/active resonant coupler (PARC) platform with tapered passive waveguide

Simarjeet Saini, Z. Dilli, Mario Dagenais, F. Johnson, Dennis Stone, Hongen Shen, Jagadeesh Pamulapati

Proceedings Volume 4087, (2000) https://doi.org/10.1117/12.406406

KEYWORDS: Waveguides, Control systems, Quantum wells, Etching, Computer engineering, Physical sciences, Analytical research, Active optics, Integrated optics, Directional couplers

Read Abstract +

Proceedings Article | 5 September 2000 Paper

Self-mixing detector candidates for an FM/cw ladar architecture

William Ruff, John Bruno, Stephen Kennerly, Ken Ritter, Paul Shen, Barry Stann, Michael Stead, Zoltan Sztankay, Mary Tobin

Proceedings Volume 4035, (2000) https://doi.org/10.1117/12.397787

KEYWORDS: Sensors, LIDAR, Modulation, Modulators, Signal detection, Quantum wells, Optical amplifiers, Reflectivity, Receivers, Avalanche photodetectors

Read Abstract +

Proceedings Article | 17 July 2000 Paper

Interdigitated finger semiconductor photodetector for optoelectronic mixing

Paul Shen, Michael Stead, Monica Taysing-Lara, Jagadeesh Pamulapati, William Ruff, Barry Stann, Parvez Uppal

Proceedings Volume 4028, (2000) https://doi.org/10.1117/12.391758

KEYWORDS: Sensors, LIDAR, Solids, Signal detection, Modulation, Electrodes, Semiconductors, Diamond, Photodetectors, Optoelectronics

Read Abstract +

Proceedings Article | 13 July 2000 Paper

Multichannel parallel free-space VCSEL optoelectronic interconnects for digital data transmission and processing

J. Jiang Liu, William Lawler, Brian Riely, Wayne Chang, Paul Shen, Peter Newman, Monica Taysing-Lara, Kimberly Olver, Bikash Koley, Mario Dagenais, George Simonis

Proceedings Volume 4046, (2000) https://doi.org/10.1117/12.391941

KEYWORDS: Vertical cavity surface emitting lasers, Receivers, Photodetectors, Optical interconnects, Image processing, Transmitters, Data transmission, Optoelectronics, Sensors, Signal processing

Read Abstract +

Proceedings Article | 1 May 2000 Paper

Research on VCSEL interconnect and OE processing research at Army Research Laboratory

George Simonis, J. Jiang Liu, Bikash Koley, Mario Dagenais, Joseph Mait, Peter Newman, Bill Lawler, Wayne Chang, Paul Shen, Monica Taysing-Lara, Madhumita Datta

Proceedings Volume 3946, (2000) https://doi.org/10.1117/12.384374

KEYWORDS: Vertical cavity surface emitting lasers, Optoelectronics, Sensors, Image processing, Analytical research, Electronics, Image compression, Optical components, Digital electronics, Oxidation

Read Abstract +

Proceedings Article | 19 April 2000 Paper

Monolithically integrated semiconductor active and passive optical waveguide devices grown by selective epitaxy

Weimin Zhou, Hongen Shen, Matthew Ervin, J. Conrad, Jagadeesh Pamulapati

Proceedings Volume 3950, (2000) https://doi.org/10.1117/12.382153

KEYWORDS: Waveguides, Modulators, Quantum wells, Ear, Etching, Photonic integrated circuits, Amplifiers, Epitaxy, Semiconductors, Cladding

Read Abstract +

Proceedings Article | 13 April 2000 Paper

High-performance GaN/AlGaN-based ultraviolet photodetectors

John Carrano, Ting Li, Charles Collins, Ariane Beck, Shuling Wang, Bo Yang, Damien Lambert, Christopher Eiting, Russell Dupuis, Joe Campbell, Michael Wraback, Hongen Shen, Matthew Schurman, Ian Ferguson

Proceedings Volume 3948, (2000) https://doi.org/10.1117/12.382125

KEYWORDS: Gallium nitride, Ultraviolet radiation, Quantum efficiency, Photodetectors, Photodiodes, PIN photodiodes, Absorption, Avalanche photodetectors, Resistance, Diffusion

Read Abstract +

Proceedings Article | 13 April 2000 Paper

Ultraviolet detector materials and devices studied by femtosecond nonlinear optical techniques

Michael Wraback, Hongen Shen, Patrick Kung, Manijeh Razeghi, John Carrano, Ting Li, Joe Campbell

Proceedings Volume 3948, (2000) https://doi.org/10.1117/12.382137

KEYWORDS: Gallium nitride, Picosecond phenomena, Absorption, Photons, Femtosecond phenomena, Reflectivity, Sapphire, Ultrafast phenomena, Ultraviolet detectors, Diodes

Read Abstract +

Proceedings Article | 6 August 1999 Paper

Polarization-sensitive optically addressed light modulators based on excitonic optical nonlinearities in optically anisotropic materials

Michael Wraback, Hongen Shen

Proceedings Volume 3625, (1999) https://doi.org/10.1117/12.356873

KEYWORDS: Polarization, Modulators, Excitons, Absorption, Anisotropy, Picosecond phenomena, Zinc oxide, Nonlinear optics, Modulation, Polarizers

Proceedings Article | 26 July 1999 Paper

8x8 arrays of VCSEL/CMOS and photodetectors: optoelectronic interconnects

John Pham, George Simonis, Jagadeesh Pamulapati, William Lawler, Paul Shen, J. Jiang Liu, Wayne Chang, Peter Newman, Monica Taysing-Lara, Bikash Koley, Mario Dagenais

Proceedings Volume 3714, (1999) https://doi.org/10.1117/12.354688

KEYWORDS: Vertical cavity surface emitting lasers, Sensors, Photodetectors, Signal detection, Optoelectronics, Optical interconnects, Modulation, Signal attenuation, Detector arrays, Chemical elements

Read Abstract +

Proceedings Article | 14 April 1999 Paper

Alignment-tolerant structures for ease of optoelectronic packaging

Mario Dagenais, Simarjeet Saini, Vijayanand Vusirikala, Robert Bartolo, Ralph Whaley, Z. Dilli, Y. Hu, Zhencan Fan, F. Johnson, Paul Shen, Jagadeesh Pamulapati, Weimin Zhou, Dennis Stone

Proceedings Volume 3626, (1999) https://doi.org/10.1117/12.345423

KEYWORDS: Waveguides, Single mode fibers, Packaging, Semiconductor lasers, Refractive index, Optical alignment, Tolerancing, Fiber lasers, Optoelectronic packaging, Quantum wells

Read Abstract +

Proceedings Article | 1 April 1999 Paper

1.55-um Er-doped GaN LED

Hongen Shen, Jagadeesh Pamulapati, Monica Taysing-Lara, M. Wood, Richard Lareau, Matthew Ervin, John Mackenzie, Fan Ren, Corinne Abernathy, John Zavada

Proceedings Volume 3622, (1999) https://doi.org/10.1117/12.344498

KEYWORDS: Erbium, Gallium nitride, Silicon, Semiconductors, Electroluminescence, Annealing, Ions, Dielectrics, Light emitting diodes, Diodes

Read Abstract +

Proceedings Article | 4 December 1998 Paper

Polarization controllable and monolithically integrable optical waveguide devices

Weimin Zhou, Jagadeesh Pamulapati, Hongen Shen

Proceedings Volume 3491, (1998) https://doi.org/10.1117/12.328765

KEYWORDS: Waveguides, Polarization, Modulators, Phase shifts, Quantum wells, Semiconducting wafers, Semiconductors, Microwave radiation, Optical semiconductors, Phased array optics

Read Abstract +

Proceedings Article | 7 April 1998 Paper

Fabrication and characterization of GaN-based blue light-emitting diodes

Yuxin Li, Michael Brown, Ivan Eliashevich, T. DiCarlo, Chuong Tran, Robert Karlicek, Richard Stall, L. Koszi, Yu Lu, Hongen Shen

Proceedings Volume 3279, (1998) https://doi.org/10.1117/12.304416

KEYWORDS: Light emitting diodes, Gallium nitride, Indium gallium nitride, Temperature metrology, Electroluminescence, Quantum wells, Blue light emitting diodes, Ultraviolet radiation, Excitons, Electrons

Read Abstract +

Proceedings Article | 19 April 1996 Paper

Strain-engineered semiconductor heterostructures for novel optoelectronic devices

Hongen Shen

Proceedings Volume 2694, (1996) https://doi.org/10.1117/12.238383

KEYWORDS: Quantum wells, Polarization, Absorption, Semiconductors, Optoelectronic devices, Excitons, Heterojunctions, Polarizers, Modulators, Thin films

Read Abstract +

Proceedings Article | 2 June 1994 Paper

Normal incidence multiple quantum well light modulator with exceedingly high contrast ratio

Hongen Shen, Jagadeesh Pamulapati, Michael Wraback, Monica Taysing-Lara, Peter Newman, Mitra Dutta, Haochung Kuo, Yicheng Lu

Proceedings Volume 2145, (1994) https://doi.org/10.1117/12.177136

KEYWORDS: Polarization, Modulators, Quantum wells, Excitons, Photon polarization, Absorption, Phase shift keying, Amplitude modulation, Birefringence, Gallium arsenide

Read Abstract +

Proceedings Article | 26 May 1994 Paper

Optical study of lift-off multiple quantum well thin films under various types of thermally induced in-plane strain

Hongen Shen, Michael Wraback, Jagadeesh Pamulapati, Monica Taysing-Lara, Weimin Zhou, Mitra Dutta, Yu Lu, Haochung Kuo

Proceedings Volume 2141, (1994) https://doi.org/10.1117/12.176853

KEYWORDS: Thin films, Gallium arsenide, Absorption, Quantum wells, Anisotropy, Temperature metrology, Thermography, Glasses, Polarization, Birefringence

Read Abstract +

Proceedings Article | 3 September 1992 Paper

Effect of electric field, both external and built-in, on GaAs-AlAs structures

Mitra Dutta, Hongen Shen, Jagadeesh Pamulapati, Peter Newman, Michael Stroscio

Proceedings Volume 1675, (1992) https://doi.org/10.1117/12.137618

KEYWORDS: Quantum wells, Gallium arsenide, Physics, Superlattices, Oscillators, Luminescence, Excitons, Phonons, Electronics, Surface plasmons

Read Abstract +

Proceedings Article | 3 September 1992 Paper

Raman and photoluminescence studies of porous silicon

James Harvey, Hongen Shen, David Morton, Robert Lux, Weimin Zhou, Mitra Dutta, Raphael Tsu

Proceedings Volume 1675, (1992) https://doi.org/10.1117/12.137588

KEYWORDS: Silicon, Raman spectroscopy, Luminescence, Dielectrics, Microcrystalline materials, Crystals, Temperature metrology, Phonons, Particles, Etching

Read Abstract +

Proceedings Article | 3 September 1992 Paper

Excitonic recombination of degenerate two-dimensional electrons with localized photoexcited holes in a single heterojunction quantum well

Patrick Folkes, Mitra Dutta, Sergey Rudin, Hongen Shen, Monica Taysing-Lara, Doran Smith, Peter Newman, Melanie Cole

Proceedings Volume 1675, (1992) https://doi.org/10.1117/12.137601

KEYWORDS: Electrons, Excitons, Quantum wells, Luminescence, Gallium arsenide, Superlattices, Physics, Heterojunctions, Scattering, Interfaces

Read Abstract +

Proceedings Article | 1 July 1992 Paper

Effect of annealing on Fermi level pinning of low-temperature molecular-beam epitaxial GaAs

Hongen Shen, Jagadeesh Pamulapati, Robert Lux, Mitra Dutta, F. Rong, Monica Taysing-Lara, L. Fotiadis, L. Calderon, Yicheng Lu

Proceedings Volume 1678, (1992) https://doi.org/10.1117/12.60458

KEYWORDS: Gallium arsenide, Annealing, Arsenic, Solids, Neodymium, Interfaces, Solar energy, Absorption, Ionization, Helium neon lasers

Read Abstract +

Proceedings Article | 1 July 1992 Paper

Refractive index approximations from linear perturbation theory for planar MQW waveguides

Gregory Alman, Hongen Shen, Lynne Molter, Mitra Dutta

Proceedings Volume 1679, (1992) https://doi.org/10.1117/12.60471

KEYWORDS: Waveguides, Refractive index, Wave propagation, Physics, Optoelectronic devices, Dielectrics, Quantum wells, Magnetism, Planar waveguides, Fourier transforms

Read Abstract +

Proceedings Article | 1 July 1992 Paper

Direct measurement of the piezoelectric field and Fermi level pinning in [111]B grown InGaAs/GaAs heterostructures

Mitra Dutta, Hongen Shen, Jagadeesh Pamulapati, Wayne Chang, Michael Stroscio, Xiaoqiang Zhang, D. Kim, K. Chung, P. Ruden, Marshall Nathan

Proceedings Volume 1678, (1992) https://doi.org/10.1117/12.60457

KEYWORDS: Quantum wells, Gallium arsenide, Indium gallium arsenide, Heterojunctions, Solar energy, Interfaces, Laser beam diagnostics, Piezoelectric effects, Electro optics, Excitons

Read Abstract +

Proceedings Article | 12 May 1992 Paper

Electroabsorption in high-power photoconductive switches

Hongen Shen, Robert Lux, Jagadeesh Pamulapati, Mitra Dutta, Robert Zeto

Proceedings Volume 1632, (1992) https://doi.org/10.1117/12.59061

KEYWORDS: Absorption, Switches, Electrodes, Semiconductor lasers, Data modeling, Gallium arsenide, Switching, Semiconductors, Ionization, Quenching (fluorescence)

Read Abstract +

Proceedings Article | 1 October 1990 Paper

Study of the band offset in InxGa1-xAs/GaAs system using photoreflectance of single quantum wells

Alexander Ksendzov, Hongen Shen, Fred Pollak, David Bour

Proceedings Volume 1283, (1990) https://doi.org/10.1117/12.20751

KEYWORDS: Quantum wells, Gallium arsenide, Polarization, Physics, Superlattices, Ions, Reflection, Solids, Excitons, Quantum information

Read Abstract +

Proceedings Article | 1 October 1990 Paper

Photoreflectance for in-situ monitoring of thin-film growth

Z. Hang, Fred Pollak, Hongen Shen

Proceedings Volume 1285, (1990) https://doi.org/10.1117/12.20802

KEYWORDS: Semiconductors, Gallium arsenide, Modulation, Metalorganic chemical vapor deposition, Thin films, Temperature metrology, Thin film growth, Dielectrics, Solids, Molecular beam epitaxy

Read Abstract +

Proceedings Article | 1 August 1990 Paper

Photoreflectance at elevated temperatures

Hongen Shen

Proceedings Volume 1286, (1990) https://doi.org/10.1117/12.20844

KEYWORDS: Gallium arsenide, Temperature metrology, Metalorganic chemical vapor deposition, Modulation, Spectroscopy, Absorption, Pyrometry, Indium gallium arsenide, Polishing, Laser beam diagnostics

Read Abstract +