Center for Quantum Devices - Most Downloaded Journal Articles

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13.	Gallium nitride on silicon for consumer & scalable photonics C. Bayram, K.T. Shiu, Y. Zhu, C.W. Cheng, D.K. Sadana, Z. Vashaei, E. Cicek, R. McClintock and M. Razeghi SPIE Proceedings, Vol. 8631, p. 863112-1, Photonics West, San Francisco, CA-- February 4, 2013 ...[Visit Journal] Gallium Nitride (GaN) is a unique material system that has been heavily exploited for photonic devices thanks to ultraviolet-to-terahertz spectral tunability. However, without a cost effective approach, GaN technology is limited to laboratory demonstrations and niche applications. In this investigation, integration of GaN on Silicon (100) substrates is attempted to enable widespread application of GaN based optoelectronics. Controlled local epitaxy of wurtzite phase GaN on on-axis Si(100) substrates is demonstrated via metal organic chemical vapor deposition (MOCVD). CMOS-compatible fabrication scheme is used to realize [SiO2-Si{111}-Si{100}] groove structures on conventional 200-mm Si(100) substrates. MOCVD growth (surface treatment, nucleation, initiation) conditions are studied to achieve controlled GaN epitaxy on such grooved Si(100) substrates. Scanning electron microscopy and transmission electron microscopy techniques are used to determine uniformity and defectivity of the GaN. Our results show that aforementioned groove structures along with optimized MOCVD growth conditions can be used to achieve controlled local epitaxy of wurtzite phase GaN on on-axis Si(100) substrates. [reprint (PDF)]
13.	Gain and recombination dynamics of quantum-dot infrared photodetectors H. Lim, B. Movaghar, S. Tsao, M. Taguchi, W. Zhang, A.A. Quivy, and M. Razeghi Physical Review B, 74 (20)-- November 15, 2006 ...[Visit Journal] In this paper we present a theory of diffusion and recombination in QDIPs which is an attempt to explain the recently reported values of gain in these devices. We allow the kinetics to encompass both the diffusion and capture rate limited regimes of carrier relaxation using rigorous random walk and diffusion methods. The photoconductive gains are calculated and compared with the experimental values obtained from InGaAs/InGaP/GaAs and InAs/InP QDIPs using the generation-recombination noise analysis. [reprint (PDF)]
13.	Al_xGa_1-xN Materials and Device Technology for Solar Blind Ultraviolet Photodetector Applications R. McClintock, P. Sandvik, K. Mi, F. Shahedipour, A. Yasan, C. Jelen, P. Kung, and M. Razeghi SPIE Conference, San Jose, CA, Vol. 4288, pp. 219-- January 22, 2001 ...[Visit Journal] There has been a growing interest for the development of solar blind ultraviolet (UV) photodetectors for use in a variety of applications, including early missile threat warning, flame monitoring, UV radiation monitoring and chemical/biological reagent detection. The Al_xGa_1-xN material system has emerged as the most promising approach for such devices. However, the control of the material quality and the device technology are still rather immature. We report here the metalorganic chemical vapor deposition, the n-type and the p-type doping of high quality Al_xGa_1-xN thin films on sapphire substrates over a wide range of Al concentration. [reprint (PDF)]
13.	High power asymmetrical InAsSb/InAsSbP/AlAsSb double heterostructure lasers emitting at 3.4 μm D. Wu, B. Lane, H. Mohseni, J. Diaz and M. Razeghi Applied Physics Letters 74 (9)-- March 1, 1999 ...[Visit Journal] Midinfrared lasers with an asymmetrical InPAsSb/InAsSb/AlAsSb double heterostructure are reported. Using the asymmetrical double heterostructure, p- and n-cladding layers are separately optimized; high energy-gap AlAsSb (Eg ≈ 1.5 eV) for the p-type cladding layer to reduce the leakage current, and thus to increase To, and low energy-gap InPAsSb (Eg ≈ 0.5 eV) for the n-cladding layer to have low turn-on voltage. 100-μm-width broad-area lasers with 1000 μm cavity length exhibited peak output powers of 1.88 W in pulse and 350 mW in continuous wave modes per two facets at T=80 K with To of 54 K and turn-on voltage of 0.36 V. Maximum peak output powers up to 6.7 W were obtained from a laser bar of total aperture of 400 μm width and cavity length of 1000 μm, with a differential efficiency of 34% and far-field beam divergence narrower than 40° at 80 K. [reprint (PDF)]
13.	High Performance Planar Antimony-Based Superlattice Photodetectors Using Zinc Diffusion Grown by MBE Jiakai Li, R. K. Saroj, Steven Slivken, V. H. Nguyen, Gail Brown and Manijeh Razeghi Photonics 2022, 9, 664 ...[Visit Journal] In this letter, we report a mid-wavelength infrared (MWIR) planar photodetector based on InAs/InAsSb type-II superlattices (T2SLs) that has a cut-off wavelength of 4.3 um at 77 K. The superlattice for the device was grown by molecular beam epitaxy while the planar device structure was achieved by Zinc diffusion process in a metal–organic chemical vapor deposition reactor. At 77 K, the peak responsivity and the corresponding quantum efficiency had the value of 1.42 A/W and 48% respectively at 3.7 um under -20 mV for the MWIR planar photodetector. At 77 K, the MWIR planar photodetector exhibits a dark current density of 2.0E5 A/cm^2 and the R0A value of ~3.0E2 Ohm cm^2 under -20 mV, which yielded a specific detectivity of 4.0E11 cm Hz^(1/2)/W at 3.7 um. At 150 K, the planar device showed a dark current density of 6.4E-5 A/cm^2 and a quantum efficiency of 49% at ~3.7 um under -20 mV, which yielded a specific detectivity of 2.0E11 cm Hz^(1/2)/W. [reprint (PDF)]
13.	High performance bias-selectable dual-band short-/mid-wavelength infrared photodetectors based on type-II InAs/GaSb/AlSb superlattices A.M. Hoang, G. Chen, A. Haddadi and M. Razeghi SPIE Proceedings, Vol. 8631, p. 86311K-1, Photonics West, San Francisco, CA-- February 5, 2013 ...[Visit Journal] Active and passive imaging in a single camera based on the combination of short-wavelength and mid-wavelength infrared detection is highly needed in a number of tracking and reconnaissance missions. Due to its versatility in band-gap engineering, Type-II InAs/GaSb/AlSb superlattice has emerged as a candidate highly suitable for this multi-spectral detection. In this paper, we report the demonstration of high performance bias-selectable dual-band short-/mid-wavelength infrared photodetectors based on InAs/GaSb/AlSb type-II superlattice with designed cut-off wavelengths of 2 μm and 4 μm. Taking advantages of the high performance short-wavelength and mid-wavelength single color photodetectors, back-to-back p-i-n-n-i-p photodiode structures were grown on GaSb substrate by molecular beam epitaxy. At 150 K, the short-wave channel exhibited a quantum efficiency of 55%, a dark current density of 1.0x10^-9 A/cm² at -50 mV bias voltage, providing an associated shot noise detectivity of 3.0x10¹³ Jones. The mid-wavelength channel exhibited a quantum efficiency of 33% and a dark current density of 2.6x10^-5 A/cm² at 300 mV bias voltage, resulting in a detectivity of 4.0x10¹¹ Jones. The operations of the two absorber channels are selectable by changing the polarity of applied bias voltage. [reprint (PDF)]
13.	Demonstration of Zn-Diffused Planar Long-Wavelength Infrared Photodetector Based on Type-II Superlattice Grown by MBE Rajendra K. Saroj, Van Hoang Nguyen, Steven Slivken, Gail J. Brown and Manijeh Razeghi IEEE Journal of Quantum Electronics ...[Visit Journal] We report on a planar long-wavelength infrared photodetector based on InAs/InAs1−xSbx type-II superlattice with zinc diffusion. The superlattice structures were grown by molecular beam epitaxy, followed by a post-growth Zinc diffusion process in a metal-organic chemical vapor deposition reactor. The planar photodetectors showed a peak responsivity of 2.18 A/W, under an applied bias of −20 mV, with a corresponding quantum efficiency of 44.5%, without any anti-reflection coating, and had a 100% cut-off wavelength of 8.5 μm at 77 K temperature. These photodetectors exhibit a specific peak detectivity of 3.0×10^12 cm.Hz^1/2/W, with a dark current density of 1.5 × 10−5 A/cm2 and the differential-resistance-area product of ∼8.6 × 10−1 Ω.cm2, under an applied bias of −20 mV at 77 K. A comparative study between the planar and conventional mesa isolated photodetectors was also carried out. [reprint (PDF)]
13.	Widely Tunable, Single-Mode, High-Power Quantum Cascade Lasers M. Razeghi, B. Gokden, S. Tsao, A. Haddadi, N. Bandyopadhyay, and S. Slivken SPIE Proceedings, Intergreated Photonics: Materials, Devices and Applications, SPIE Microtechnologies Symposium, Prague, Czech Republic, April 18-20, 2011, Vol. 8069, p. 806905-1-- May 31, 2011 ...[Visit Journal] We demonstrate widely tunable high power distributed feedback quantum cascade laser array chips that span 190 nm and 200 nm from 4.4 um to 4.59 um and 4.5 um to 4.7 um respectively. The lasers emit single mode with a very narrow linewidth and side mode suppression ratio of 25 dB. Under pulsed operation power outputs up to 1.85 W was obtained from arrays with 3 mm cavity length and up to 0.95 W from arrays with 2 mm cavity length at room temperature. Continuous wave operation was also observed from both chips with 2 mm and 3 mm long cavity arrays up to 150 mW. The cleaved size of the array chip with 3 mm long cavities was around 4 mm x 5 mm and does not require sensitive external optical components to achieve wide tunability. With their small size and high portability, monolithically integrated DFB QCL Arrays are prominent candidates of widely tunable, compact, efficient and high power sources of mid-infrared radiation for gas sensing. [reprint (PDF)]
13.	Surface leakage reduction in narrow band gap type-II antimonide-based superlattice photodiodes E.K. Huang, D. Hoffman, B.M. Nguyen, P.Y. Delaunay and M. Razeghi Applied Physics Letters, Vol. 94, No. 5, p. 053506-1-- February 2, 2009 ...[Visit Journal] Inductively coupled plasma (ICP) dry etching rendered structural and electrical enhancements on type-II antimonide-based superlattices compared to those delineated by electron cyclotron resonance (ECR) with a regenerative chemical wet etch. The surface resistivity of 4×10⁵ Ω·cm is evidence of the surface quality achieved with ICP etching and polyimide passivation. By only modifying the etching technique in the fabrication steps, the ICP-etched devices with a 9.3 µm cutoff wavelength revealed a diffusion-limited dark current density of 4.1×10⁻⁶ A/cm² and a maximum differential resistance at zero bias in excess of 5300 Ω·cm² at 77 K, which are an order of magnitude better in comparison to the ECR-etched devices. [reprint (PDF)]
13.	High-quality MOCVD-grown heteroepitaxial gallium oxide growth on III-nitrides enabled by AlOx interlayer Junhee Lee, Lakshay Gautam, and Manijeh Razeghi Junhee Lee, Manijeh RazeghiAppl. Phys. Lett. 123, 151902 (2023) https://doi.org/10.1063/5.0170383 ...[Visit Journal] We report high-quality Ga2O3 grown on an AlGaN/AlN/Sapphire in a single growth run in the same Metal Organic Chemical Vapor Deposition reactor with an AlOx interlayer at the Ga2O3/AlGaN interface. AlOx interlayer was found to enable the growth of single crystalline Ga2O3 on AlGaN in spite of the high lattice mismatch between the two material systems. The resulting nitride/oxide heterogenous heterostructures showed superior material qualities, which were characterized by structural, electrical, and optical characterization techniques. In particular, a significant enhancement of the electron mobility of the nitride/oxide heterogenous heterostructure is reported when compared to the individual electron mobilities of the Ga2O3 epilayer on the sapphire substrate and the AlGaN/AlN heterostructure on the sapphire substrate. This enhanced mobility marks a significant step in realizing the next generation of power electronic devices and transistors. [reprint (PDF)]
13.	Suppression of surface leakage in gate controlled type-II InAs/GaSb mid-infrared photodetectors G. Chen; B.-M. Nguyen; A.M. Hoang; E.K. Huang; S.R. Darvish; M. Razeghi Proc. SPIE 8268, Quantum Sensing and Nanophotonic Devices IX, 826811 (January 20, 2012)-- January 20, 2012 ...[Visit Journal] One of the biggest challenges of improving the electrical performance in Type II InAs/GaSb superlattice photodetector is suppressing the surface leakage. Surface leakage screens important bulk dark current mechanisms, and brings difficulty and uncertainty to the material optimization and bulk intrinsic parameters extraction such as carrier lifetime and mobility. Most of surface treatments were attempted beyond the mid-infrared (MWIR) regime because compared to the bulk performance, surface leakage in MWIR was generally considered to be a minor factor. In this work, we show that below 150K, surface leakage still strongly affects the electrical performance of the very high bulk performance p-π-M-n MWIR photon detectors. With gating technique, we can effectively eliminate the surface leakage in a controllable manner. At 110K, the dark current density of a 4.7 μm cut-off gated photon diode is more than 2 orders of magnitude lower than the current density in SiO₂ passivated ungated diode. With a quantum efficiency of 48%, the specific detecivity of gated diodes attains 2.5 x 10¹⁴ cm·Hz^1/2/W, which is 3.6 times higher than that of ungated diodes. [reprint (PDF)]
13.	Quantum oscillations at a Ga0.47In0.53AsInP heterojunction interface R.J Nicholas a, M.A Brummell a , J.C Portal b, M Razeghi c, M.A Poisson R.J Nicholas, M.A Brummell, J.C Portal, M Razeghi, M.A Poisson, Quantum oscillations at a Ga0.47In0.53AsInP heterojunction interface, Solid State Communications, Volume 43, Issue 11, 1982, Pages 825-828,-- September 1, 1982 ...[Visit Journal] We report the observation of a two dimensional gas of high mobility electrons at the interface of a Ga0.47In0.53AsInP heterojunction grown by MOCVD. The two dimensional electron concentrations and effective mass are determined by Shubnikov-de Haas studies, and compared with theoretical predictions. Evidence of an enhancement of the g-factor is observed. We also report observations of very pronounced quantum Hall steps as seen in GaAs-GaAlAs heterojunctions. [reprint (PDF)]
13.	Metalorganic chemical vapor deposition of undoped In1−xAlxAs on InP M. A. di Forte‐Poisson; M. Razeghi; J. P. Duchemin M. A. di Forte‐Poisson, M. Razeghi, J. P. Duchemin; Metalorganic chemical vapor deposition of undoped In1−xAlxAs on InP. J. Appl. Phys. 1 December 1983; 54 (12): 7187–7189. https://doi.org/10.1063/1.331956-- December 1, 1983 ...[Visit Journal] In1−x Alx As epitaxial layers were grown on (100) InP substrates by the organometallic vapor phase epitaxy method. Undoped layers with mirror smooth surfaces were obtained for substrate temperatures of 600–650 °C. By adjusting the relative ratio of In and Al, lattice matched In0.52 Al0.48 As epilayers were reproducibly grown on InP substrates. X‐ray measurements, scanning Auger analyses, and electron mobilities are presented. These results show that the quality of the epilayers obtained here was comparable to the best reported layers grown by other methods. [reprint (PDF)]
13.	First observation of the two‐dimensional properties of the electron gas in Ga0.49In0.51P/GaAs heterojunctions grown by low pressure metalorganic chemical vapor deposition M. Razeghi; P. Maurel; F. Omnés; S. Ben Armor; L. Dmowski; J. C. Portal M. Razeghi, P. Maurel, F. Omnés, S. Ben Armor, L. Dmowski, J. C. Portal; First observation of the two‐dimensional properties of the electron gas in Ga0.49In0.51P/GaAs heterojunctions grown by low pressure metalorganic chemical vapor deposition. Appl. Phys. Lett. 12 May 1986; 48 (19): 1267–1269-- June 12, 1986 ...[Visit Journal] We report the first observation of a two‐dimensional electron gas from Shubnikov–de Haas and quantum hall effect experiments in GaInP/GaAs heterostructures grown by low pressure metalorganic chemical vapor deposition. Angular‐dependent Shubnikov–de Haas measurements confirm two dimensionality of the system. Low‐temperature persistent photoconductivity was observed. Critical density at which the second electric subband starts to be populated was determined to be 7.3×1011 cm−2. [reprint (PDF)]
13.	Room temperature quantum cascade lasers with 27% wall plug efficiency Y. Bai, N. Bandyopadhyay, S. Tsao, S. Slivken and M. Razeghi Applied Physics Letters, Vol. 98, No. 18, p. 181102-1-- May 3, 2011 ...[Visit Journal] Using the recently proposed shallow-well design, we demonstrate InP based quantum cascade lasers (QCLs) emitting around 4.9 μm with 27% and 21% wall plug efficiencies in room temperature (298 K) pulsed and continuous wave (CW) operations, respectively. The laser core consists of 40 QCL-stages. The highest cw efficiency is obtained from a buried-ridge device with a ridge width of 8 μm and a cavity length of 5 mm. The front and back facets are antireflection and high-reflection coated, respectively. The maximum single facet cw power at room temperature amounts to 5.1 W. [reprint (PDF)]
13.	Demonstration of mid-wavelength infrared nBn photodetectors based on type-II InAs/InAs_1-xSb_x superlattice grown by metal-organic chemical vapor deposition Donghai Wu, Arash Dehzangi, and Manijeh Razeghi Appl. Phys. Lett. 115, 061102-- August 6, 2019 ...[Visit Journal] We report design, growth, and characterization of midwavelength infrared nBn photodetectors based on a type-II InAs/InAs_1-xSb_x superlattice on a GaSb substrate grown by metal-organic chemical vapor deposition. An InAs/AlAs_1-ySb_y/InAs/InAs_1-xSb_x superlattice design was used as the large bandgap electron barrier in the photodetectors. At 150 K, the photodetector exhibits a peak responsivity of 1.23 A/W, corresponding to a quantum efficiency of 41% at an applied bias voltage of −100 mV under front-side illumination, with a 50% cut-off wavelength of 4.6 μm. With an R × A of 356 Ω·cm² and a dark current density of 1.6 × 10⁻⁴ A/cm² under an applied bias of −100 mV at 150 K, the photodetector exhibits a specific detectivity of 1.4 × 10¹¹ cm·Hz^1/2/W. [reprint (PDF)]
13.	Two‐dimensional electron gas in a In0.53Ga0.47As‐InP heterojunction grown by metalorganic chemical vapor deposition Y. Guldner; J. P. Vieren; P. Voisin; M. Voos; M. Razeghi; M. A. Poisson Y. Guldner, J. P. Vieren, P. Voisin, M. Voos, M. Razeghi, M. A. Poisson; Two‐dimensional electron gas in a In0.53Ga0.47As‐InP heterojunction grown by metalorganic chemical vapor deposition. Appl. Phys. Lett. 15 May 1982; 40 (10): 877–879.-- April 15, 1982 ...[Visit Journal] We report, from Shubnikov-de Haas and cyclotron resonance experiments, the first observation of a two-dimensional, high-mobility electron gas in a selectively doped 1110.53 G~l.47 As-InP heterojunction grown by metalorganic chemical vapor deposition. Several parameters of the electronic system under consideration are determined. [reprint (PDF)]
13.	GaInAs/InP nanopillar arrays for long wavelength infrared detection A. Gin, Y. Wei, A. Hood, D. Hoffman, M. Razeghi and G.J. Brown SPIE Conference, Jose, CA, Vol. 5732, pp. 350-- January 22, 2005 ...[Visit Journal] Nanopillar devices have been fabricated from GaInAs/InP QWIP material grown by MOCVD. Using electron beam lithography and reactive ion etching techniques, large, regular arrays of nanopillars with controllable diameters ranging from 150 nm to less than 40 nm have been reproducibly formed. Photoluminescence experiments demonstrate a strong peak wavelength blue shift for nanopillar structures compared to the as-grown quantum well material. Top and bottom metal contacts have been realized using a polyimide planarization and etchback procedure. I-V and noise measurements have been performed. Optical measurements indicate photoconductive response in selected nanopillar arrays. Device peak wavelength response occurs at about 8 µm with peak device responsivity of 420 mA/W. Peak detectivity of 3×10⁸ cm·Hz^½/W has been achieved at -1V bias and 30 K. [reprint (PDF)]
13.	Scaling in back-illuminated GaN avalanche photodiodes K. Minder, J.L. Pau, R. McClintock, P. Kung, C. Bayram, M. Razeghi and D. Silversmith Applied Physics Letters, Vol. 91, No. 7, p. 073513-1-- August 13, 2007 ...[Visit Journal] Avalanche p-i-n photodiodes of various mesa areas were fabricated on AlN templates for back illumination for enhanced performance through hole-initiated multiplication, and the effects of increased area on device performance were studied. Avalanche multiplication was observed in mesa sizes up to 14,063 µm^2 under linear mode operation. Uniform gain and a linear increase of the dark current with area were demonstrated. [reprint (PDF)]
13.	Type-II InAs/GaSb Superlattice Focal Plane Arrays for High-Performance Third Generation Infrared Imaging and Free-Space Communication M. Razeghi, A. Hood and A. Evans SPIE Conference, January 25-29, 2007, San Jose, CA Proceedings – Optoelectronic Integrated Circuits IX, Vol. 6476, p. 64760Q-1-9-- January 29, 2007 ...[Visit Journal] Free-space optical communications has recently been touted as a solution to the "last mile" bottleneck of high speed data networks providing highly secure, short to long range, and high bandwidth connections. However, commercial near infrared systems experience atmospheric scattering losses and scintillation effects which can adversely affect a link's uptime. By moving the operating wavelength into the mid or long wavelength infrared enhanced link uptimes and increased range can be achieved due to less susceptibility atmospheric affects. The combination of room temperature, continuous wave' high power quantum cascade lasers and high operating temperature Type-II superlattice photodetectors offers the benefits of mid and long wavelength infrared systems as well as practical operating conditions. [reprint (PDF)]
13.	High Performance Quantum Cascade Laser Results at the Centre for Quantum Devices M. Razeghi and S. Slivken Physica Status Solidi, 195 (1)-- January 1, 2003 ...[Visit Journal] In this paper, we review some of the history and recent results related to the development of the quantum cascade laser at the Center for Quantum Devices. The fabrication of the quantum cascade laser is described relative to growth, characterization, and processing. State-of-the-art testing results for 5-11 μm lasers will be then be explored, followed by a future outlook for the technology. [reprint (PDF)]
13.	High Detectivity InAs Quantum-Dot Infrared Photodetectors Grown on InP by Metalorganic Chemical Vapor Deposition W. Zhang, H. Lim, M. Taguchi, S. Tsao, B. Movaghar, and M. Razeghi Applied Physics Letters, 86 (19)-- May 9, 2005 ...[Visit Journal] We report a high-detectivity InAs quantum-dot infrared photodetector. The InAs quantum dots were grown by self-assembly on InP substrates via low-pressure metal–organic chemical–vapor deposition. Highly uniform quantum dots with a density of 4×10¹⁰ cm² were grown on a GaAs/InP matrix. Photoresponse was observed at temperatures up to 160 K with a peak of 6.4 µm and cutoff of 6.6 µm. Very low dark currents and noise currents were obtained by inserting Al_0.48In_0.52As current blocking layers. The background-limited performance temperature was 100 K. A detectivity of 1.0×10¹⁰ cm·Hz^½/W was obtained at 77 K with a bias of –1.1 V. [reprint (PDF)]
13.	Investigation of the Heteroepitaxial Interfaces in the GaInP/GaAs Superlattices by High Resolution X-Ray Diffraction and Dynamical Solutions Xiaoguang He and Manijeh Razeghi Journal of Applied Physics 73 (7)-- April 1, 1993 ...[Visit Journal] Two GaAs/GaInP superlattices grown on GaAs substrates by low‐pressure metalorganic chemical vapor deposition have been studied using high resolution x‐ray diffraction measurements and simulations by solving Tagaki–Taupin equations. The strained layers at both interfaces of the GaAs well are identified from the simulations of the measured diffraction patterns. The purging of indium at the interface of GaInP/GaAs accounts for the strained layer at the GaInP/GaAs interface while the pressure difference in the gas lines, which results in the different traveling time to the sample surface, is attributed to the indium‐poor strained layer at the GaAs/GaInP interface. It is shown that high‐resolution x‐ray diffraction measurements combined with a dynamical simulation, are sensitive tools to study the heteroepitaxial interfaces on an atomic layer scale. In addition, the influence of a miscut of the substrate on the measurement is discussed in the article. It is shown that even though the miscut is small, the diffraction geometry is already an asymmetric one. More than 10% error in the superlattice period for a 2° miscut substrate can result when the miscut substrate is considered a symmetric geometry. [reprint (PDF)]
13.	Ga/sub 0.51/In/sub 0.49/P/GaAs HEMT's exhibiting good electrical performance at cryogenic temperatures Y.-J. Chan; D. Pavlidis; M. Razeghi; F. Omnes IEEE TRANS. ELEC.DEVICES. 77. IO. 1990-- October 1, 1990 ...[Visit Journal] The DC and microwave characteristics of Ga/sub 0.51/In/sub 0.49/P/GaAs HEMTs grown by metalorganic chemical vapor deposition (MOCVD) are presented. Devices with 1- mu m-long gates show transconductances of 163 and 213 mS/mm at 300 and 77 K, respectively. Their maximum cutoff frequency is 17.8 GHz. Deep traps in the doped layer are evaluated at low temperature by the threshold voltage shift and current collapse phenomena. GaInP/GaAs HEMTs show no current collapse and have almost zero threshold voltage shift compared to AlGaAs/GaAs and InAlAs/InGaAs where the corresponding values are 0.5 and 0.25 V, respectively. [reprint (PDF)]
13.	Intermixing of GaInP/GaAs Multiple Quantum Wells C. Francis, M.A. Bradley, P. Boucaud, F.H. Julien and M. Razeghi Applied Physics Letters 62 (2)-- January 11, 1993 ...[Visit Journal] The intermixing of GaInP‐GaAs superlattices induced by a heat treatment is investigated as a function of the annealing temperature and duration. Photoluminescence experiments reveal a large red shift of the effective band gap of the annealed quantum wells thus indicating a dominant self‐diffusion of the group III atoms which is confirmed by secondary ion mass spectroscopic measurements. For long enough annealing durations, the red shift saturates and even decreases due to the competing slower self‐diffusion of the group V atoms. Experiments are well understood based on a simple diffusion model. [reprint (PDF)]

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