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Sanjay Krishna - One of the best experts on this subject based on the ideXlab platform.
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modeling and extraction of optical characteristics of inas gasb Strained Layer superlattice
Infrared Technology and Applications XLVI, 2020Co-Authors: Nicole Pfiester, Jordan Budhu, Seung Hyun Lee, Vinita Dahiya, Kwongkit Choi, C D Ball, Steve M Young, Anthony Grbic, Sanjay KrishnaAbstract:With the increasing use of resonant structures in optical devices, broadband optical characterization of the refractive index and extinction coefficient is necessary for accurate simulation and device design. For resonance-enhanced photodetectors, the complex refractive index is necessary to impedance match not only the resonator to air, minimizing the reflection, but also the resonator to the detector element, ensuring absorption occurs in the photodiode. To work towards better resonator-detector coupling, we present the complex refractive index for GaSb and an InAs/GaSb Strained Layer superlattice designed to be the absorber Layer for a long-wave infrared photodetector. The optical properties were extracted using spectroscopic ellipsometry. Several modeling methods will be discussed for both the superlattice and the single-side polished bulk GaSb. Comparison to transmission and reflection values as well as absorption coefficients from literature provide additional confidence in the extraction process. Future work will incorporate these values into a resonance-enhanced photodetector.
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comparison of mwir unipolar barrier structures based on Strained Layer superlattices conference presentation
Proceedings of SPIE, 2016Co-Authors: David A. Ramirez, Christian P. Morath, S Myers, Elizabeth H Steenbergen, Yuliya Kuznetsova, Sen Mathews, T Schulersandy, Vicent M Cowan, Sanjay KrishnaAbstract:In this work, we compare the performance of three MWIR unipolar barrier structures based on the InAs/GaSb Type-2 Strained Layer superlattice material system. We have designed, fabricated, and characterized pBiBn, pBn, and pBp detector structures. All the structures have been designed so that the cut off wavelength is around 5 microns at 100 K. We fabricated single-pixel devices and characterize their radiometric performance. In addition, we have characterized the degradation of the performance of the devices after exposing the devices to 63 MeV proton radiation to total ionizing dose of 100 kRad (Si). In this report, we compare the performance of the different structures with the objective of determining the advantages and disadvantages of the different designs. This work was supported by the Small Business Innovation Research (SBIR) program under the contract FA9453-14-C-0032, sponsored by the Air Force Research Laboratory (AFRL).
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dual color longwave inas gasb type ii Strained Layer superlattice detectors
Infrared Physics & Technology, 2015Co-Authors: Elena Plis, David A. Ramirez, S Myers, E P G Smith, David R Rhiger, Chihyu Chen, J D Phillips, Sanjay KrishnaAbstract:Abstract We report on the design, growth, fabrication and characterization of dual-band (long-/long-wave infrared) type-II InAs/GaSb Strained Layer superlattice (T2SL) detectors with pBp architecture. Under operating the bias of −200 mV and +100 mV, quantum efficiencies of 37% (∼11 μm band) and 25% (∼9 μm band) were realized, respectively. To reduce the dark current in a dual-band T2SL detector, the effect of a “restoration” chemical etch treatment and ZnTe passivation on device performance were investigated.
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radiation tolerance of type ii Strained Layer superlattice based interband cascade infrared photodetectors icip
Proceedings of SPIE, 2013Co-Authors: Vincent M. Cowan, Christian P. Morath, Laura A. Treider, N Gautam, Zhaobing Tian, Sanjay KrishnaAbstract:For space-based imaging systems radiation tolerance to both displacement damage and total ionizing dose (TID) radiation effects continues to be a major performance concern. Here, the TID and proton irradiance tolerance of mid wave infrared interband cascade infrared photodetectors (ICIPs) based on InAs/GaSb type II Strained-Layer superlattice (T2SLS) absorbers is presented. Protons of energy of 63 MeV were used to irradiate the unbiased ICIP detectors at room temperature to a proton fluence of 7.5 x 1011 protons/cm2, corresponding to a TID of 100 kRads(Si). A comparison of the detector performance of a variety of ICIPs with different numbers of electron barrier sizes cascade stages is presented. Performance of detectors of varying size was characterized by dark current and quantum efficiency measurements at different temperatures. Results show changes, increase in dark current and a reduction in the quantum efficiency, consistent with an increase in the trap density.
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passivation techniques for inas gasb Strained Layer superlattice detectors
Laser & Photonics Reviews, 2013Co-Authors: Elena Plis, M N Kutty, Sanjay KrishnaAbstract:InAs/(In,Ga)Sb Strained Layer Superlattices (SLSs) have made significant progress since they were first proposed as an infrared (IR) sensing material more than three decades ago. The basic material properties of SLS provide a prospective benefit in the realization of IR imagers with suppressed interband tunneling and Auger recombination processes, as well as high quantum efficiency and responsivity. With scaling of single pixel dimensions, the performance of focal plane arrays is strongly dependent on surface effects due to the large pixels’ surface/volume ratio. This article discusses the cause of surface leakage currents and various approaches of their reduction including dielectric passivation, passivation with organic materials (polyimide or various photoresists), passivation by overgrowth of wider bandgap material, and chalcogenide passivation. Performance of SLS detectors passivated by different techniques and operating in various regions of infrared spectrum has been compared.
Hitoshi Umemoto - One of the best experts on this subject based on the ideXlab platform.
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ingan gan algan based laser diodes with modulation doped Strained Layer superlattices grown on an epitaxially laterally overgrown gan substrate
Applied Physics Letters, 1998Co-Authors: Shuji Nakamura, Masayuki Senoh, Shinichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Hiroyuki Kiyoku, Yasunobu Sugimoto, Tokuya Kozaki, Hitoshi UmemotoAbstract:InGaN multi-quantum-well-structure laser diodes with Al0.14Ga0.86N/GaN modulation doped Strained-Layer superlattice cladding Layers grown on an epitaxially laterally overgrown GaN (ELOG) substrate was demonstrated to have a lifetime of more than 1150 h under room-temperature continuous-wave operation. After 4 μm etching of the ELOG substrate, the etch pit density was about 2×108 cm2 in the region of the 4-μm-wide stripe window, but almost zero in the region of the 7-μm-wide SiO2 stripe.
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ingan gan algan based laser diodes with modulation doped Strained Layer superlattices grown on an epitaxially laterally overgrown gan substrate
Applied Physics Letters, 1998Co-Authors: Shuji Nakamura, Masayuki Senoh, Shinichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Hiroyuki Kiyoku, Yasunobu Sugimoto, Tokuya Kozaki, Hitoshi UmemotoAbstract:InGaN multi-quantum-well-structure laser diodes with Al0.14Ga0.86N/GaN modulation doped Strained-Layer superlattice cladding Layers grown on an epitaxially laterally overgrown GaN (ELOG) substrate was demonstrated to have a lifetime of more than 1150 h under room-temperature continuous-wave operation. After 4 μm etching of the ELOG substrate, the etch pit density was about 2×108 cm2 in the region of the 4-μm-wide stripe window, but almost zero in the region of the 7-μm-wide SiO2 stripe.
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ingan gan algan based laser diodes with modulation doped Strained Layer superlattices
Japanese Journal of Applied Physics, 1997Co-Authors: Shuji Nakamura, Masayuki Senoh, Shinichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Hiroyuki Kiyoku, Yasunobu Sugimoto, Tokuya Kozaki, Hitoshi UmemotoAbstract:InGaN multi-quantum-well-structure laser diodes with Al0.14Ga0.86N/GaN modulation doped Strained-Layer superlattice cladding Layers grown on an epitaxially laterally overgrown GaN substrate were demonstrated to have an estimated lifetime of more than 10000 h under continuous-wave operation at 20° C. Under operation at a high temperature of 50° C, the lifetime was longer than 1000 h. With the operating current increasing to above the threshold, a self-pulsation with a high frequency of 3.5 GHz was observed. The carrier lifetime was estimated to be 1.8 ns from the pulsed modulation of the LDs.
Elena Plis - One of the best experts on this subject based on the ideXlab platform.
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dual color longwave inas gasb type ii Strained Layer superlattice detectors
Infrared Physics & Technology, 2015Co-Authors: Elena Plis, David A. Ramirez, S Myers, E P G Smith, David R Rhiger, Chihyu Chen, J D Phillips, Sanjay KrishnaAbstract:Abstract We report on the design, growth, fabrication and characterization of dual-band (long-/long-wave infrared) type-II InAs/GaSb Strained Layer superlattice (T2SL) detectors with pBp architecture. Under operating the bias of −200 mV and +100 mV, quantum efficiencies of 37% (∼11 μm band) and 25% (∼9 μm band) were realized, respectively. To reduce the dark current in a dual-band T2SL detector, the effect of a “restoration” chemical etch treatment and ZnTe passivation on device performance were investigated.
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passivation techniques for inas gasb Strained Layer superlattice detectors
Laser & Photonics Reviews, 2013Co-Authors: Elena Plis, M N Kutty, Sanjay KrishnaAbstract:InAs/(In,Ga)Sb Strained Layer Superlattices (SLSs) have made significant progress since they were first proposed as an infrared (IR) sensing material more than three decades ago. The basic material properties of SLS provide a prospective benefit in the realization of IR imagers with suppressed interband tunneling and Auger recombination processes, as well as high quantum efficiency and responsivity. With scaling of single pixel dimensions, the performance of focal plane arrays is strongly dependent on surface effects due to the large pixels’ surface/volume ratio. This article discusses the cause of surface leakage currents and various approaches of their reduction including dielectric passivation, passivation with organic materials (polyimide or various photoresists), passivation by overgrowth of wider bandgap material, and chalcogenide passivation. Performance of SLS detectors passivated by different techniques and operating in various regions of infrared spectrum has been compared.
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performance improvement of long wave infrared inas gasb Strained Layer superlattice detectors through sulfur based passivation
Infrared Physics & Technology, 2012Co-Authors: Elena Plis, M N Kutty, S Myers, A Rathi, E H Aifer, I Vurgaftman, Sanjay KrishnaAbstract:Abstract We report on effective sulfur-based passivation treatments of type-II InAs/GaSb Strained Layer superlattice detectors (100% cut-off wavelength is 9.8 μm at 77 K). The electrical behavior of detectors passivated by electrochemical sulfur deposition (ECP) and thioacetamide (TAM) was evaluated for devices of various sizes. ECP passivated detectors with a perimeter-to-area ratio of 1600 cm −1 exhibited superior performance with surface resistivity in excess of 10 4 Ω cm, dark current density of 2.7 × 10 −3 A/cm 2 , and specific detectivity improved by a factor of 5 compared to unpassivated devices ( V Bias = − 0.1 V, 77 K).
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passivation of long wave infrared inas gasb Strained Layer superlattice detectors
Infrared Physics & Technology, 2011Co-Authors: Elena Plis, L R Dawson, M N Kutty, N Gautam, S Myers, H S Kim, Sanjay KrishnaAbstract:Abstract We have investigated various passivation techniques for type-II InAs/GaSb Strained Layer superlattice (SLS) detectors with p-i-n and PbIbN designs with a 100%-cut-off wavelength of ∼12 μm at 77 K. The passivation schemes include dielectric deposition (silicon nitride (SiN x ), silicon dioxide (SiO 2 ), photoresist (SU-8)), chalcogenide treatments (zinc sulfide (ZnS), ammonium sulfide [(NH 4 ) 2 S]), and electrochemical sulphur deposition. [(NH 4 ) 2 S] passivation and electrochemical sulphur passivation (ECP) showed the better performances, improving the dark current density by factors of 200 and 25 (p-i-n detector) and ∼3 and 54 (PbIbN detector), respectively ( T = 77 K, −0.1 V of applied bias). The specific detectivity D * was improved by a factor of 2 and by an order of magnitude for (NH 4 ) 2 S and ECP passivated PbIbN detectors, respectively.
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varshni parameters for inas gasb Strained Layer superlattice infrared photodetectors
Journal of Physics D, 2011Co-Authors: B Klein, Elena Plis, M N Kutty, N Gautam, S Myers, Alexander R Albrecht, Sanjay KrishnaAbstract:The temperature-dependent behaviour of the bandgap of mid- and long-wavelength as well as dual-colour (mid-/long-wavelength) infrared detectors based on InAs/GaSb Strained Layer superlattices (SLSs) with p-i-n and nBn designs has been investigated with temperature-dependent absorption, photoluminescence and spectral response techniques. Values of Varshni parameters, zero temperature bandgap E0 and empirical coefficient α, were extracted and tabulated. The MWIR and LWIR superlattice detectors showed a temperature change of 0.325 meV K−1 and 0.282 meV K−1, respectively. These values are a factor of two lower than that of HgCdTe and InSb, making them attractive for higher operating temperatures.
Shuji Nakamura - One of the best experts on this subject based on the ideXlab platform.
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ingan gan algan based laser diodes with modulation doped Strained Layer superlattices grown on an epitaxially laterally overgrown gan substrate
Applied Physics Letters, 1998Co-Authors: Shuji Nakamura, Masayuki Senoh, Shinichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Hiroyuki Kiyoku, Yasunobu Sugimoto, Tokuya Kozaki, Hitoshi UmemotoAbstract:InGaN multi-quantum-well-structure laser diodes with Al0.14Ga0.86N/GaN modulation doped Strained-Layer superlattice cladding Layers grown on an epitaxially laterally overgrown GaN (ELOG) substrate was demonstrated to have a lifetime of more than 1150 h under room-temperature continuous-wave operation. After 4 μm etching of the ELOG substrate, the etch pit density was about 2×108 cm2 in the region of the 4-μm-wide stripe window, but almost zero in the region of the 7-μm-wide SiO2 stripe.
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ingan gan algan based laser diodes with modulation doped Strained Layer superlattices grown on an epitaxially laterally overgrown gan substrate
Applied Physics Letters, 1998Co-Authors: Shuji Nakamura, Masayuki Senoh, Shinichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Hiroyuki Kiyoku, Yasunobu Sugimoto, Tokuya Kozaki, Hitoshi UmemotoAbstract:InGaN multi-quantum-well-structure laser diodes with Al0.14Ga0.86N/GaN modulation doped Strained-Layer superlattice cladding Layers grown on an epitaxially laterally overgrown GaN (ELOG) substrate was demonstrated to have a lifetime of more than 1150 h under room-temperature continuous-wave operation. After 4 μm etching of the ELOG substrate, the etch pit density was about 2×108 cm2 in the region of the 4-μm-wide stripe window, but almost zero in the region of the 7-μm-wide SiO2 stripe.
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ingan gan algan based laser diodes with modulation doped Strained Layer superlattices
Japanese Journal of Applied Physics, 1997Co-Authors: Shuji Nakamura, Masayuki Senoh, Shinichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Hiroyuki Kiyoku, Yasunobu Sugimoto, Tokuya Kozaki, Hitoshi UmemotoAbstract:InGaN multi-quantum-well-structure laser diodes with Al0.14Ga0.86N/GaN modulation doped Strained-Layer superlattice cladding Layers grown on an epitaxially laterally overgrown GaN substrate were demonstrated to have an estimated lifetime of more than 10000 h under continuous-wave operation at 20° C. Under operation at a high temperature of 50° C, the lifetime was longer than 1000 h. With the operating current increasing to above the threshold, a self-pulsation with a high frequency of 3.5 GHz was observed. The carrier lifetime was estimated to be 1.8 ns from the pulsed modulation of the LDs.
Naruhito Iwasa - One of the best experts on this subject based on the ideXlab platform.
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ingan gan algan based laser diodes with modulation doped Strained Layer superlattices grown on an epitaxially laterally overgrown gan substrate
Applied Physics Letters, 1998Co-Authors: Shuji Nakamura, Masayuki Senoh, Shinichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Hiroyuki Kiyoku, Yasunobu Sugimoto, Tokuya Kozaki, Hitoshi UmemotoAbstract:InGaN multi-quantum-well-structure laser diodes with Al0.14Ga0.86N/GaN modulation doped Strained-Layer superlattice cladding Layers grown on an epitaxially laterally overgrown GaN (ELOG) substrate was demonstrated to have a lifetime of more than 1150 h under room-temperature continuous-wave operation. After 4 μm etching of the ELOG substrate, the etch pit density was about 2×108 cm2 in the region of the 4-μm-wide stripe window, but almost zero in the region of the 7-μm-wide SiO2 stripe.
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ingan gan algan based laser diodes with modulation doped Strained Layer superlattices grown on an epitaxially laterally overgrown gan substrate
Applied Physics Letters, 1998Co-Authors: Shuji Nakamura, Masayuki Senoh, Shinichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Hiroyuki Kiyoku, Yasunobu Sugimoto, Tokuya Kozaki, Hitoshi UmemotoAbstract:InGaN multi-quantum-well-structure laser diodes with Al0.14Ga0.86N/GaN modulation doped Strained-Layer superlattice cladding Layers grown on an epitaxially laterally overgrown GaN (ELOG) substrate was demonstrated to have a lifetime of more than 1150 h under room-temperature continuous-wave operation. After 4 μm etching of the ELOG substrate, the etch pit density was about 2×108 cm2 in the region of the 4-μm-wide stripe window, but almost zero in the region of the 7-μm-wide SiO2 stripe.
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ingan gan algan based laser diodes with modulation doped Strained Layer superlattices
Japanese Journal of Applied Physics, 1997Co-Authors: Shuji Nakamura, Masayuki Senoh, Shinichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Hiroyuki Kiyoku, Yasunobu Sugimoto, Tokuya Kozaki, Hitoshi UmemotoAbstract:InGaN multi-quantum-well-structure laser diodes with Al0.14Ga0.86N/GaN modulation doped Strained-Layer superlattice cladding Layers grown on an epitaxially laterally overgrown GaN substrate were demonstrated to have an estimated lifetime of more than 10000 h under continuous-wave operation at 20° C. Under operation at a high temperature of 50° C, the lifetime was longer than 1000 h. With the operating current increasing to above the threshold, a self-pulsation with a high frequency of 3.5 GHz was observed. The carrier lifetime was estimated to be 1.8 ns from the pulsed modulation of the LDs.