Center for Quantum Devices - Most Downloaded Journal Articles

Page 13 of 25: Prev << 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 >> Next (605 Items)

2.	Two-dimensional magnetophonon resonance in GaInAs-InP and GaInAs-AlInAs heterojunctions and superlattices J.C. Portal, G. Gregoris a b , M.A. Brummell , R.J. Nicholas, M. Razeghi, M.A. Di Forte-Poisson, K.Y. Cheng, A.Y. Cho J.C. Portal, G. Gregoris, M.A. Brummell, R.J. Nicholas, M. Razeghi, M.A. Di Forte-Poisson, K.Y. Cheng, A.Y. Cho, Two-dimensional magnetophonon resonance in GaInAs-InP and GaInAs-AlInAs heterojunctions and superlattices, Surface Science, Volume 142, Issues 1–3, 1984, Pages 368-374,-- July 1, 1984 ...[Visit Journal] We report the observation of magnetophonon resonance in GaInAs-InP heterojunctions and measurements of the temperature dependence of the oscillations. A single series of oscillations due to scattering by the “GaAs-like” mode of GaInAs is seen, in contrast to GaInAs-InP superlattices, where scattering from InP phonons is also observed, and GaInAs-AlInAs heterojunctions, where coupling to “InAs-like” modes only is seen. This behaviour is discussed in terms of long-range phonon interactions and interface phonons. [reprint (PDF)]
2.	High Performance Quantum Cascade Lasers at λ ~ 6 μm M. Razeghi, S. Slivken, J. Yu, A. Evans, and J. David Microelectronics Journal, 34 (5-8)-- May 1, 2003 ...[Visit Journal] This talk will focus on the recent efforts at the Center for Quantum Devices to deliver a high average power quantum cascade laser source at λ ~6 μm. Strain-balancing is used to reduce leakage for these shorter wavelength quantum cascade lasers. Further, the effect of reducing the doping in the injector is explored relative to the threshold current density and maximum average output power. Lastly, to demonstrate more of the potential of these devices, epilayer down bonding is explored as a technique to significantly enhance device performance. [reprint (PDF)]
2.	MOCVD challenge for III-V semiconductor materials for photonic and electronic devices on alternative substrates M. Razeghi, M. Defour , F. Omnes, P. Maurel , E. Bigan , O. Acher, J. Nagle, F. Brillouet , J.C. Portal M. Razeghi, M. Defour, F. Omnes, P. Maurel, E. Bigan, O. Acher, J. Nagle, F. Brillouet, J.C. Portal, MOCVD challenge for III-V semiconductor materials for photonic and electronic devices on alternative substrates, Journal of Crystal Growth, Volume 93, Issues 1–4, 1988, Pages 776-781,-- January 1, 1988 ...[Visit Journal] High quality II[-V semiconductor heterojunctions, quantum wells and superlauices have been grown on lattice matched and alternative substrates such as silicon for photonic and electronic devices, using low pressure metalorganic chemical vapor deposition growth technique. [reprint (PDF)]
2.	High operability 1024 x 1024 long wavelength infrared focal plane array base on Type-II InAs/GaSb superlattice A. Haddadi, S.R. Darvish, G. Chen, A.M. Hoang, B.M. Nguyen and M. Razeghi AIP Conference Proceedings, Vol. 1416, p. 56-58_NGS15 Conf_Blacksburg, VA_Aug 1-5, 2011-- December 31, 2011 ...[Visit Journal] Fabrication and characterization of a high performance 1024×1024 long wavelength infrared type‐II superlattice focal plane array are described. The FPA performs imaging at a continous rate of 15.00 frames/sec. Each pixel has pitch of 18μm with a fill factor of 71.31%. It demonstrates excellent operability of 95.8% and 97.4% at 81 and 68K operation temperature. The external quantum efficiency is ∼81% without any antireflective coating. Using F∕2 optics and an integration time of 0.13ms, the FPA exhibits an NEDT as low as 27 and 19mK at operating temperatures of 81 and 68K respectively. [reprint (PDF)]
2.	Fabrication of GaN Nanotubular Material using MOCVD with an Aluminium Oxide Membrane W.G. Jung, S.H. Jung, P. Kung, and M. Razeghi Nanotechnology 17-- January 1, 2006 ...[Visit Journal] GaN nanotubular material is fabricated with an aluminium oxide membrane in MOCVD. SEM, XRD, TEM and PL are employed to characterize the fabricated GaN nanotubular material. An aluminium oxide membrane with ordered nanoholes is used as a template. Gallium nitride is deposited at the inner wall of the nanoholes in the aluminium oxide template, and the nanotubular material with high aspect ratio is synthesized using the precursors of TMG and ammonia gas. Optimal synthesis conditions in MOCVD are obtained successfully for the gallium nitride nanotubular material in this research. The diameter of the GaN nanotube fabricated is approximately 200–250 nm and the wall thickness is about 40–50 nm. [reprint (PDF)]
2.	Noise analysis in type-II InAs/GaSb focal plane arrays P.Y. Delaunay and M. Razeghi Journal of Applied Physics, Vol. 106, Issue 6, p. 063110-- September 15, 2009 ...[Visit Journal] A long wavelength infrared focal plane array based on type-II InAs/GaSb superlattices was fabricated and characterized at 80 K. The noise equivalent temperature difference in the array was measured as low as 23 mK for an integration time of 0.129 ms. The noise behavior of the detectors was properly described by a model based on thermal, shot, read out integrated circuit, and photon noises. The noise of the imager was dominated by photon noise for photon fluxes higher than 1.8×10¹⁵ ph·s⁻¹·cm⁻². At lower irradiance, the imager was limited by the shot noise generated by the dark current or the noise of the testing system. The superlattice detector did not create 1/f noise for frequencies above 4 mHz. As a result, the focal plane array did not require frequent calibrations. [reprint (PDF)]
2.	Status of III-V semiconductor thin films and their applications to future OEICs Manijeh Razeghi Proc. SPIE 10267, Integrated Optics and Optoelectronics, 102670T -- June 26, 2017 ...[Visit Journal] In the last decade, semiconductor technology has been advanced to a great extent in terms of electronic and photonic discrete devices. One of the main reasons for such a progress, is the result of advancement in the epitaxial growth techniques such as molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD), where device quality films can be grown with great control over composition, uniformity and thickness. MOCVD has proven to be one of the best growth methods for many IH-V semiconductor thin films 1. Its flexibility and potential to yield a broad range of growth rates resulted in the layers featuring the thicknesses from tens of microns down to several nanometers. Planar structures containing quantum wells with atomically flat interfaces, superlattices, strained or graded-index layers were successfully grown by MOCVD. Furthermore, MOCVD proved its efficiency in producing a laser devices by overgrowth and epitaxy on patterned substrates. The importance of MOCVD is strongly enhanced by the possibility of large-scale production by simultaneous growth on several substrates in one process. Several III-V semiconductor films with bandgaps ranging from infrared to ultraviolet (15 to 0.2 μm) have been successfully grown by MOCVD. [reprint (PDF)]
2.	Low irradiance background limited type-II superlattice MWIR M-barrier imager E.K. Huang, S. Abdollahi Pour, M.A. Hoang, A. Haddadi, M. Razeghi and M.Z. Tidrow OSA Optics Letters (OL), Vol. 37, No. 11, p. 2025-2027-- June 1, 2012 ...[Visit Journal] We report a type-II superlattice mid-wave infrared 320 × 256 imager at 81 K with the M-barrier design that achieved background limited performance (BLIP) and ∼99%operability. The 280 K blackbody’s photon irradiance was limited by an aperture and a band-pass filter from 3.6 μm to 3.8 μm resulting in a total flux of ∼5 × 10¹² ph·cm⁻²·s⁻¹. Under these low-light conditions, and consequently the use of a 13.5 ms integration time, the imager was observed to be BLIP thanks to a ∼5 pA dark current from the 27 μm wide pixels. The total noise was dominated by the photon flux and read-out circuit which gave the imager a noise equivalent input of ∼5 × 10¹⁰ ph·cm⁻²·s⁻¹ and temperature sensitivity of 9 mK with F∕2.3 optics. Excellent imagery obtained using a 1-point correction alludes to the array’s uniform responsivity. [reprint (PDF)]
2.	Self-assembled semiconductor quantum dot infrared photodetector operating at room temperature and focal plane array Ho-Chul Lim; Stanley Tsao; Wei Zhang; Manijen Razeghi Proc. SPIE 6542, Infrared Technology and Applications XXXIII, 65420R (May 14, 2007)-- May 14, 2007 ...[Visit Journal] Self-assembled semiconductor quantum dots have attracted much attention because of their novel properties and thus possible practical applications including the lasers, detectors and modulators. Especially the photodetectors which have quantum dots in their active region have been developed and show promising performances such as high operation temperature due to three dimensional confinement of the carriers and normal incidence in contrast to the case of quantum well detectors which require special optical coupling schemes. Here we report our recent results for mid-wavelength infrared quantum dot infrared photodetector grown by low-pressure metalorganic chemical vapor deposition. The material system we have investigated consists of 25 period self-assembled InAs quantum dot layers on InAlAs barriers, which are lattice-matched to InP substrates, covered with InGaAs quantum well layers and InAlAs barriers. This active region was sandwiched by highly doped InP contact layers. The device operates at 4.1 μm with a peak detectivity of 2.8×10¹¹ cm·Hz^1/2/W at 120 K and a quantum efficiency of 35 %. The photoresponse can be observed even at room temperature resulting in a peak detectivity of 6×10⁷ cm·Hz^1/2/W. A 320×256 focal plane array has been fabricated in this kind of device. Its performance will also be discussed here. [reprint (PDF)]
2.	Optoelectronic Integrated Circuits (OEICs) for Next Generation WDM Communications M. Razeghi and S. Slivken SPIE Conference, Boston, MA, -- July 29, 2002 ...[Visit Journal] This paper reviews some of the key enabling technologies for present and future optoelectronic intergrated circuits. This review concentrates mainly on technology for lasers, waveguides, modulators, and fast photodetectors as the basis for next generation communicatiosn systems. Emphasis is placed on intergrations of components and mass production of a generic intelligent tranciever. [reprint (PDF)]
2.	High Performance InAs/GaSb Superlattice Photodiodes for the Very Long Wavelength Infrared Range H. Mohseni, M. Razeghi, G.J. Brown, Y.S. Park Applied Physics Letters 78 (15)-- April 9, 2001 ...[Visit Journal] We report on the demonstration of high-performance p-i-n photodiodes based on type-II InAs/GaSb superlattices with 50% cut-off wavelength λ_c = 16 μm operating at 80 K. Material is grown by molecular beam epitaxy on GaSb substrates with excellent crystal quality as evidenced by x-ray diffraction and atomic force microscopy. The processed devices show a current responsivity of 3.5 A/W at 80 K leading to a detectivity of ∼ 1.51×10¹⁰ cm·Hz^½/W. The quantum efficiency of these devices is about 35% which is comparable to HgCdTe detectors with a similar active layer thickness. [reprint (PDF)]
2.	High-power high-wall plug efficiency mid-infrared quantum cascade lasers based on InP/GaInAs/InAlAs material system M. Razeghi SPIE Proceedings, San Jose, CA Volume 7230-11-- January 26, 2009 ...[Visit Journal] The latest result at the Center for Quantum Devices about high power, high wall plug efficiency, mid-infrared quantum cascade lasers (QCLs) is presented. At an emitting wavelength of 4.8 µm, an output power of 3.4 W and a wall plug efficiency of 16.5% are demonstrated from a single device operating in continuous wave at room temperature. At a longer wavelength of 10.2 µm, average power as high as 2.2 W is demonstrated at room temperature. Gas-source molecular beam epitaxy is used to grow the QCL core in an InP/GaInAs/InAlAs material system. Fe-doped semiinsulating regrowth is performed by metal organic chemical vapor deposition for efficient heat removal and low waveguide loss. This accomplishment marks an important milestone in the development of high performance midinfrared QCLs. [reprint (PDF)]
2.	High power InAsSb/InPAsSb/InAs mid-infrared lasers A. Rybaltowski, Y. Xiao, D. Wu, B. Lane, H. Yi, H. Feng, J. Diaz, and M. Razeghi Applied Physics Letters 71 (17)-- October 27, 1997 ...[Visit Journal] We demonstrate high-power InAsSb/InPAsSb laser bars (λ ≈ 3.2 μm) consisting of three 100 μm-wide laser stripes of 700 μm cavity length, with peak output power up to 3 W at 90 K, and far-fields for the direction perpendicular to the junction as narrow as 12° full width half maximum. Spectra and far-field patterns of the laser bars are shown to have excellent characteristics for a wide range of operating conditions, suggesting the possibility of even higher light power emission with good beam quality. Joule heating is shown to be the major factor limiting higher power operation. [reprint (PDF)]
2.	Room temperature single-mode terahertz sources based on intracavity difference-frequency generation in quantum cascade lasers Q.Y. Lu, N. Bandyopadhyay, S. Slivken, Y. Bai and M. Razeghi Applied Physics Letters, Vol. 99, Issue 13, p. 131106-1-- September 26, 2011 ...[Visit Journal] We demonstrate room temperature single-mode THz emission at 4 THz based on intracavity difference-frequency generation from mid-infrared dual-wavelength quantum cascade lasers. An integrated dual-period distributed feedback grating is defined on the cap layer to purify both mid-infrared pumping wavelengths and in turn the THz spectra. Single mode operation of the pumping wavelengths results in a single-mode THz operation with a narrow linewidth of 6.6 GHz. A maximum THz power of 8.5 μW with a power conversion efficiency of 10 μW/W² is obtained at room temperature. [reprint (PDF)]
2.	High performance InGaAs/InGaP quantum dot infrared photodetector achieved through doping level optimization S. Tsao, K. Mi, J. Szafraniec, W. Zhang, H. Lim, B. Movaghar, and M. Razeghi SPIE Conference, Jose, CA, Vol. 5732, pp. 334-- January 22, 2005 ...[Visit Journal] We report an InGaAs/InGaP/GaAs quantum dot infrared photodetector grown by metalorganic chemical vapor deposition with detectivity of 1.3x10¹¹ cm·Hz^½/W at 77K and 1.2x10¹⁰ ccm·Hz^½/W at 120K. Modeling of the Quantum dot energy levels showed us that increased photoresponse could be obtained by doping the quantum dots to 4 electrons per dot instead of the usual 2 electrons per dot. This happens because the primary photocurrent transition is from the first excited state to a higher excited state. Increasing the quantum doping in our device yielded significant responsivity improvement and much higher detectivity as a result. This paper discusses the performance of this higher doping device and compares it to our previously reported device with lower doping. [reprint (PDF)]
2.	Wafer-scale epitaxial lift-off of optoelectronic grade GaN from a GaN substrate using a sacrificial ZnO interlayer Akhil Rajan, David J Rogers, Cuong Ton-That, Liangchen Zhu, Matthew R Phillips, Suresh Sundaram, Simon Gautier, Tarik Moudakir, Youssef El-Gmili, Abdallah Ougazzaden, Vinod E Sandana, Ferechteh H Teherani, Philippe Bove, Kevin A Prior, Zakaria Djebbour, Ryan McClintock and Manijeh Razeghi Journal of Physics D: Applied Physics, Volume 49, Number 31 -- July 15, 2016 ...[Visit Journal] Full 2 inch GaN epilayers were lifted off GaN and c-sapphire substrates by preferential chemical dissolution of sacrificial ZnO underlayers. Modification of the standard epitaxial lift-off (ELO) process by supporting the wax host with a glass substrate proved key in enabling full wafer scale-up. Scanning electron microscopy and x-ray diffraction confirmed that intact epitaxial GaN had been transferred to the glass host. Depth-resolved cathodoluminescence (CL) analysis of the bottom surface of the lifted-off GaN layer revealed strong near-band-edge (3.33 eV) emission indicating a superior optical quality for the GaN which was lifted off the GaN substrate. This modified ELO approach demonstrates that previous theories proposing that wax host curling was necessary to keep the ELO etch channel open do not apply to the GaN/ZnO system. The unprecedented full wafer transfer of epitaxial GaN to an alternative support by ELO offers the perspective of accelerating industrial adoption of the expensive GaN substrate through cost-reducing recycling. [reprint (PDF)]
2.	GaN nanostructured p-i-n photodiodes J.L. Pau, C. Bayram, P. Giedraitis, R. McClintock, and M. Razeghi Applied Physics Letters, Vol. 93, No. 22, p. 221104-1-- December 1, 2008 ...[Visit Journal] We report the fabrication of nanostructured p-i-n photodiodes based on GaN. Each device comprises arrays of ~200 nm diameter and 520 nm tall nanopillars on a 1 µm period, fabricated by e-beam lithography. Strong rectifying behavior was obtained with an average reverse current per nanopillar of 5 fA at −5 V. In contrast to conventional GaN diodes, nanostructured devices reproducibly show ideality factors lower than 2. Enhanced tunneling through sidewall surface states is proposed as the responsible mechanism for this behavior. Under backillumination, the quantum efficiency in nanostructured devices is partly limited by the collection efficiency of holes into the nanopillars. [reprint (PDF)]
2.	Band gap tunability of Type-II Antimonide-based superlattices M. Razeghi and B.M. Nguyen Physics Procedia, Vol. 3, Issue 2, p. 1207-1212 (14th International Conference on Narrow Gap Semiconductors and Systems NGSS-14, Sendai, Japan, July 13-17, 2009)-- January 31, 2010 ...[Visit Journal] Current state-of-the art infrared photon detectors based on bulk semiconductors such as InSb or HgCdTe are now relatively mature and have almost attained the theoretical limit of performance. It means, however, that the technology can not be expected to demonstrate revolutionary improvements, in terms of device performances. In contrasts, low dimensional quantum systems such as superlattices, quantum wells, quantum dots, are still the development stage, yet have shown comparable performance to the bulk detector family. Especially for the Type-II Antimony-based superlattices, recent years have seen significant improvements in material quality, structural design as well as fabrication techniques which lift the performance of Type-II superlattice photodetectors to a new level. In this talk, we will discuss the advantages of Type-II-superlattices, from the physical nature of the material to the practical realisms. We will demonstrate the flexibility in controlling the energy gap and their overall band alignment for the suppression of Auger recombination, as well as to create sophisticated hetero-designs. [reprint (PDF)]
2.	Monolithic Integration of GaInAs/InP Quantum Well Infrared Photodetectors on Si Substrate M. Erdtmann and M. Razeghi SPIE Conference, San Jose, CA, -- January 22, 2001 ...[Visit Journal] Using low-pressure metalorganic chemical vapor deposition, we have grown GaInAs/InP QWIP structures on GaAs-coated Si substrate. First, the procedure to optimize the epitaxy of the InP buffer layer on Si substrate is given. Excellent crystallinity and a mirror-like surface morphology were obtained by using both a two-step growth process at the beginning of the InP buffer layer growth and several series of thermal cycle annealing throughout the InP buffer layer growth. Second, results of fabricated GaInAs/InP QWIPs on Si substrate are presented. At a temperature of 80 K, the peak response wavelength occurs at 7.4 μm. The responsivities of QWIPs on both Si and InP substrates with identical structures are equal up to biases of 1.5 V. At a bias of 3 V, the responsivity of the QWIPs on Si substrate is 1.0 A/W. [reprint (PDF)]
2.	High operating temperature MWIR photon detectors based on Type-II InAs/GaSb superlattice M. Razeghi, B.M. Nguyen, P.Y. Delaunay, S. Abdollahi Pour, E.K.W. Huang, P. Manukar, S. Bogdanov, and G. Chen SPIE Proceedings, San Francisco, CA (January 22-28, 2010), Vol. 7608, p. 76081Q-1-- January 22, 2010 ...[Visit Journal] Recent efforts have been paid to elevate the operating temperature of Type-II InAs/GaSb superlattice Mid Infrared photon detectors. Optimized growth parameters and interface engineering technique enable high quality material with a quantum efficiency above 50%. Intensive study on device architecture and doping profile has resulted in almost one order of magnitude of improvement to the electrical performance and lifted up the 300 K-background BLIP operation temperature to 166 K. At 77 K, the ~4.2 µm cut-off devices exhibit a differential resistance area product in excess of the measurement system limit (10⁶ Ω·cm²) and a detectivity of 3x10¹³ cm·Hz^½·W⁻¹. High quality focal plane arrays were demonstrated with a noise equivalent temperature of 10 mK at 77 K. Uncooled camera is capable to capture hot objects such as soldering iron. [reprint (PDF)]
2.	Passivation of Type-II InAs/GaSb superlattice photodetectors A. Hood, Y. Wei, A. Gin, M. Razeghi, M. Tidrow, and V. Nathan SPIE Conference, Jose, CA, Vol. 5732, pp. 316-- January 22, 2005 ...[Visit Journal] Leakage currents limit the operation of high performance Type-II InAs/GaSb superlattice photodiode technology. Surface leakage current becomes a dominant limiting factor, especially at the scale of a focal plane array pixel (< 25 µm) and must be addressed. A reduction of the surface state density, unpinning the Fermi level at the surface, and appropriate termination of the semiconductor crystal are all aims of effective passivation. Recent work in the passivation of Type-II InAs\GaSb superlattice photodetectors with aqueous sulfur-based solutions has resulted in increased R₀A products and reduced dark current densities by reducing the surface trap density. Additionally, photoluminescence of similarly passivated Type-II InAs/GaSb superlattice and InAs GaSb bulk material will be discussed. [reprint (PDF)]
2.	The effect of doping the M-barrier in very long-wave type-II InAs/GaSb heterodiodes D. Hoffman, B.M. Nguyen, E.K. Huang, P.Y. Delaunay, M. Razeghi, M.Z. Tidrow and J. Pellegrino Applied Physics Letters, Vol. 93, No. 3, p. 031107-1-- July 21, 2008 ...[Visit Journal] A variation on the standard homo-diode Type-II superlattice with an M-barrier between the pi-region and the n-region is shown to suppress the dark currents. By determining the optimal doping level of the M-superlattice, dark current densities of 4.95 mA·cm^-2 and quantum efficiencies in excess of 20% have been demonstrated at the moderate reverse bias of 50 mV; allowing for near background-limited performance with a Johnson-noise detectivity of 3.11×10¹⁰ Jones at 77 K for a 14.58 µm cutoff wavelength for large area diodes without passivation. This is comparable to values for the state-of-the-art HgCdTe photodiodes. [reprint (PDF)]
2.	InP-based quantum-dot infrared photodetectors with high quantum efficiency and high temperature imaging S. Tsao, H. Lim, H. Seo, W. Zhang and M. Razeghi IEEE Sensors Journal, Vol. 8, No. 6, p. 936-941-- June 1, 2008 ...[Visit Journal] We report a room temperature operating InAs quantum-dot infrared photodetector grown on InP substrate. The self-assembled InAs quantum dots and the device structure were grown by low-pressure metalorganic chemical vapor depositon. The detectivity was 6 x 10¹⁰cm·Hz^1/2·W^-1 at 150 K and a bias of 5 V with a peak detection wavelength around 4.0 micron and a quantum efficiency of 48%. Due to the low dark current and high responsivity, a clear photoresponse has been observed at room temperature. A 320 x 256 middle wavelength infrared focal plane array operating at temperatures up to 200 K was also demonstrated. The focal plane array had 34 mA/W responsivity, 1.1% conversion efficiency, and noise equivalent temperature difference of 344 mK at 120 K operating temperature. [reprint (PDF)]
2.	Development of material quality and structural design for high performance type-II InAs/GaSb superlattice photodiodes and focal plane arrays M. Razeghi, B.M. Nguyen, D. Hoffman, P.Y. Delaunay, E.K. Huang, M.Z. Tidrow and V. Nathan SPIE Porceedings, Vol. 7082, San Diego, CA 2008, p. 708204-- August 11, 2008 ...[Visit Journal] Recent progress made in the structure design, growth and processing of Type-II InAs/GaSb superlattice photo-detectors lifted both the quantum efficiency and the R0A product of the detectors. Type-II superlattice demonstrated its ability to perform imaging in the Mid-Wave Infrared (MWIR)and Long-Wave Infrared (LWIR) ranges, becoming a potential competitor for technologies such as Quantum Well Infrared Photo-detectors (QWIP) and Mercury Cadmium Telluride (MCT). Using an empirical tight-binding model, we developed superlattices designs that were nearly lattice-matched to the GaSb substrates and presented cutoff wavelengths of 5 and 11 μm. We demonstrated high quality material growth with X-ray FWHM below 30 arcsec and an AFM rms roughness of 1.5 Å over an area of 20x20 μm2. The detectors with a 5 μm cutoff, capable of operating at room temperature, showed a R0A of 1.25 106 Ω.cm2 at 77K, and a quantum efficiency of 32%. In the long wavelength infrared, we demonstrated high quantum efficiencies above 50% with high R0A products of 12 Ω.cm2 by increasing the thickness of the active region. Using the novel M-structure superlattice design, more than one order of magnitude improvement has been observed for electrical performance of the devices. Focal plane arrays in the middle and long infrared range, hybridized to an Indigo read out integrated circuit, exhibited high quality imaging. [reprint (PDF)]
2.	Passivation of type-II InAs/GaSb double heterostructure P.Y. Delaunay, A. Hood, B.M. Nguyen, D. Hoffman, Y. Wei, and M. Razeghi Applied Physics Letters, Vol. 91, No. 9, p. 091112-1-- August 27, 2007 ...[Visit Journal] Focal plane array fabrication requires a well passivated material that is resistant to aggressive processes. The authors report on the ability of type-II InAs/GaSb superlattice heterodiodes to be more resilient than homojunctions diodes in improving sidewall resistivity through the use of various passivation techniques. The heterostructure consisting of two wide band gap (5 µm) superlattice contacts and a low band gap active region (11 µm) exhibits an R₀A averaging of 13·Ω cm². The devices passivated with SiO₂, Na₂S and SiO₂ or polyimide did not degrade compared to the unpassivated sample and the resistivity of the sidewalls increased to 47 kΩ·cm. [reprint (PDF)]

Page 13 of 25: Prev << 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 >> Next (605 Items)