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576.  Room Temperature Operation of InTlSb Infrared Photodetectors on GaAs
J.D. Kim, E. Michel, S. Park, J. Xu, S. Javadpour and M. Razeghi
Applied Physics Letters 69 (3)-- August 15, 1996
Long-wavelength InTlSb photodetectors operating at room temperature are reported. The photo- detectors were grown on (100) semi-insulating GaAs substrates by low-pressure metalorganic chemical vapor deposition. Photoresponse of InTlSb photodetectors is observed up to 11 µm at room temperature. The maximum responsivity of an In0.96Tl0.04Sb photodetector is about 6.64 V/W at 77 K, corresponding to a detectivity of about 7.64 × 108 cm·Hz½/W. The carrier lifetime in InTlSb photodetectors derived from the stationary photoconductivity is 10–50 ns at 77 K. reprint
 
577.  Observation of inversion layers at AlN-Si interfaces fabricated by metal organic chemical vapour deposition
X. Zhang, D. Walker, A. Saxler, P. Kung, J. Xu, and M. Razeghi
-- August 15, 1996
 
578.  Demonstration of an Electronic Grade Ti/AlN/Si Metal-Insulator-Semiconductor Capacitor
X. Zhang, D. Walker, A. Saxler, P. Kung, J. Xu, and M. Razeghi
-- August 1, 1996
 
579.  The Molecular Beam Epitaxial Growth of InSb on (111) GaAs
E. Michel, J. Kim, J. Xu, S. Javadpour, I. Ferguson, and M. Razeghi
Applied Physics Letters 69 (2)-- July 8, 1996
The molecular beam epitaxial growth of InSb on (111)B GaAs has been investigated. It was found that for a given Sb/In ratio, a higher growth temperature was required for the growth of InSb on (111)B GaAs compared to that on (001) GaAs. This difference has been attributed to the bonding characteristics of the (111)B and (001) surface. Once growth had been optimized, it was found that the material characteristics of (111)B InSb were almost identical to that of (001) InSb, i.e., independent of orientation. For example, the x-ray full width at half-maximum and 300 K mobility had the same absolute values for (111) InSb and (001)InSb and followed the same dependence with the sample thickness. Te was found to be a well-behaved n-type dopant for (111)B InSb. reprint
 
580.  Comparison of Gain and Threshold Current Density for InGaAsP/GaAs λ = 808 nm) Lasers with Different Quantum-Well Thickness
H.J. Yi, J. Diaz, I. Eliashevich, G. Lukas, S. Kim, D. Wu, M. Erdtmann, C. Jelen, S. Slivken, L.J. Wang, and M. Razeghi
Journal of Applied Physics 79 (11)-- July 1, 1996
We investigated the quantum‐size effects of quantum well (QW) on gain and threshold current density for InGaAsP/GaAs (λ=808 nm) laser diodes. In this work, a comparison is made of lasers with different QW thickness while keeping the optical confinement factors constant. We found that the threshold current density and differential efficiency were not affected by narrowing the QW thickness. The theoretical model taking into account the mixing of the valence bands and momentum relaxation for InGaAsP/GaAs lasers with spontaneous emission (optically pumped) measurement shows that the absence of difference between these structures can be attributed to the high relaxation rate. reprint
 
581.  Semiconductor ultraviolet detectors
M. Razeghi and A. Rogalski
Journal of Applied Physics Applied Physics Review 79 (10)-- May 15, 1996
In this review article a comprehensive analysis of the developments in ultraviolet (UV) detector technology is described. At the beginning, the classification of UV detectors and general requirements imposed on these detectors are presented. Further considerations are restricted to modern semiconductor UV detectors, so the basic theory of photoconductive and photovoltaic detectors is presented in a uniform way convenient for various detector materials. Next, the current state of the art of different types of semiconductor UV detectors is presented. Hitherto, the semiconductor UV detectors have been mainly fabricated using Si. Industries such as the aerospace, automotive, petroleum, and others have continuously provided the impetus pushing the development of fringe technologies which are tolerant of increasingly high temperatures and hostile environments. As a result, the main efforts are currently directed to a new generation of UV detectors fabricated from wide band-gap semiconductors the most promising of which are diamond and AlGaN. The latest progress in development of AlGaN UV detectors is finally described in detail. reprint
 
582.  InSb Infrared Photodetectors on Si Substrates Grown by Molecular Beam Epitaxy
E. Michel, J. Xu, J.D. Kim, I. Ferguson, and M. Razeghi
IEEE Photonics Technology Letters 8 (5) pp. 673-- May 1, 1996
The InSb infrared photodetectors grown heteroepitaxially on Si substrates by molecular beam epitaxy (MBE) are reported. Excellent InSb material quality is obtained on 3-in Si substrates (with a GaAs predeposition) as confirmed by structural, optical, and electrical analysis. InSb infrared photodetectors on Si substrates that can operate from 77 K to room temperature have been demonstrated. The peak voltage-responsitivity at 4 μm is about 1.0×103 V/W and the corresponding Johnson-noise-limited detectivity is calculated to be 2.8×1010 cm·Hz½/W. This is the first important stage in developing InSb detector arrays or monolithic focal plane arrays (FPAs) on silicon. The development of this technology could provide a challenge to traditional hybrid FPA's in the future. reprint
 
583.  AlGaN ultraviolet photoconductors grown on sapphire
D. Walker, X. Zhang, P. Kung, A. Saxler, S. Javadpour, J. Xu, and M. Razeghi
Applied Physics Letters 68 (15)-- April 8, 1996
AlxGa1−xN (0≤x≤0.50) ultraviolet photoconductors with a minimum cutoff wavelength shorter than 260 nm have been fabricated and characterized. The AlGaN active layers were grown on (00⋅1) sapphire substrates by metalorganic chemical vapor deposition (MOCVD). The spectral responsivity of the GaN detector at 360 nm is about 1 A/W biased at 8 V at room temperature. The carrier lifetime derived from the voltage‐dependent responsivity is 0.13–0.36 ms. reprint
 
584.  Aluminum nitride films on different orientations of sapphire and silicon
K. Dovidenko, S. Oktyabrsky, J. Narayan, and M. Razeghi
Journal of Applied Physics79 (5)-- March 1, 1996
The details of epitaxial growth and microstrictural characteristics of AlN films grown on sapphire (0001), (1012) and Si (100), (111) substrates were investigated using plan‐view and cross‐sectional high‐resolution transmission electron microscopy and x‐ray diffraction techniques. The films were grown by metalorganic chemical vapor deposition using TMA1+NH3+N2 gas mixtures. Different degrees of epitaxy were observed for the films grown on α‐Al2O3 and Si substrates in different orientations. The epitaxial relationship for (0001) sapphire was found to be (0001)AlN∥(0001)sap with in‐plane orientation relationship of [0110]AlN∥[1210]sap. This is equivalent to a 30° rotation in the basal (0001) plane. For (1012) sapphire substrates, the epitaxial relationship was determined to be (1120)AlN∥(1012)sap with the in‐plane alignment of [0001]AlN∥[1011]sap. The AlN films on (0001) α‐Al2O3 were found to contain inverted domain boundaries and a/3〈1120〉 threading dislocations with the estimated density of 1010 cm−2. The density of planar defects (stacking faults) found in AlN films was considerably higher in the case of (1012) compared to (0001) substrates. Films on Si substrates were found to be highly textured c axis oriented when grown on (111) Si, and c axis textured with random in‐plane orientation on (100) Si. The role of thin‐film defects and interfaces on device fabrication is discussed. reprint
 
585.  Optical Absorption and Photoresponse in fully Quaternary p-type Quantum Well Detectors
J. Hoff, C. Jelen, S. Slivken, G.J. Brown, and M. Razeghi
SPIE Photonics West '96 Photodetectors: Materials and Devices; Proceedings 2685-- January 27, 1996
Acceptor doped, non-strained aluminum-free Quantum Well Intersubband Photodetectors lattice matched to GaAs with Ga0.79In0.21As0.59P0.41 wells and Ga0.62In0.38As0.22P0.78 barriers have been demonstrated on semi-insulating GaAs substrates. These devices which operate at normal incidence demonstrate a unique spectral response which extends from approximately 2 μm up to 10 μm. To explain such a broad spectral shape, a detailed theoretical analysis based on the 8 x 8 Kane Hamiltonian was necessary to probe all aspect of optical absorption. The results of this analysis revealed that spectral shape results from the influence of the Spin Split-off band on the band structure and the optical matrix. reprint
 
586.  Sb-based infrared materials and photodetectors for the 3-5 and 8-12 μm range
E. Michel, J.D. Kim, S. Park, J. Xu, I. Ferguson, and M. Razeghi
SPIE Photonics West '96 'Photodetectors: Materials and Devices'; Proceedings 2685-- January 27, 1996
In this paper, we report on the growth of InSb on (100) Si and (111)B GaAs substrates and the growth of InAsSb alloys for longer wavelength applications. The fabrication and characterization of photodetectors based on these materials are also reported. Both photoconductive and photovoltaic devices are investigated. The photodiodes are InSb p-i-n structures and InSb/InAs1-xSbx/InSb double heterostructures grown on (100) and (111)B semi-insulating GaAs and Si substrates by low pressure metalorganic chemical vapor deposition and solid source molecular beam epitaxy. The material parameters for device structures have been optimized through theoretical calculations based on fundamental mechanisms. InSb p-i-n photodiodes with peak responsivities approximately 103 V/W were grown on Si and (111) GaAs substrates. An InAsSb photovoltaic detector with a composition of x equals 0.85 showed photoresponse up to 13 micrometers at 300 K with a peak responsivity of 9.13 X 10-2 V/W at 8 micrometers . The R0A product of InAsSb detectors has been theoretically and experimentally analyzed. reprint
 
587.  Semiconductor ultraviolet detectors
M. Razeghi and A. Rogalski
SPIE Photonics West '96 Photodetectors: Materials and Devices; Proceedings 2685-- January 27, 1996
This paper presents an overview of semiconductor ultraviolet (UV) detectors that are currently available and associated technologies that are undergoing further development. At the beginning, the classification of UV detectors and general requirements imposed on these detectors are presented. Further consideration are restricted to modern semiconductor UV detectors, so the current state-of-the-art of different types of semiconductor UV detectors is presented. Hitherto, the semiconductor UV detectors have been mainly fabricated using Si. Industries such as the aerospace, automotive, petroleum, and others have continuously provided the impetus pushing the development of fringe technologies which are tolerant of increasingly high temperatures and hostile environments. As a result, the main effort are currently directed to a new generation of UV detectors fabricated from wide-band-gap semiconductors between them the most promising are diamond and AlGaN. The latest progress in development of AlGaN UV detectors is finally described in detail. reprint
 
588.  GaN, GaAlN, and AlN for use in UV Detectors for Astrophysics: An Update
P. Kung, A. Saxler, X. Zhang, D. Walker, M. Razeghi, and M. Ulmer
SPIE Photonics West '96 Photodetectors: Materials and Devices; Proceedings 2685-- January 27, 1996
In SPIE Proceeding 2397 we demonstrated that there is a large payoff still to be gained by further improvements in the performance of solar blind UV detectors for astronomical purposes. We suggested that a particularly promising future technology is one based on the ability of investigators to produce high-quality films made of wide bandgap III-IV semiconductors. Here we report on significant progress we have made over the past year to fabricate and test single-pixel devices. The next step will be to measure and improve detective efficiency, measure the solar blindness over a larger dynamic range, and begin developing multiple-pixel designs. reprint
 
589.  UV photodetectors based on AlxGa1-xN grown by MOCVD
A. Saxler, D. Walker, X. Zhang, P. Kung, J. Xu, and M. Razeghi
SPIE Photonics West '96 Photodetectors: Materials and Devices; Proceedings 2685-- January 27, 1996
Metalorganic chemical vapor deposition was used to deposit AlxGa1-xN active layers with varying aluminum compositions on basal plane sapphire substrate. AlxGa1-xN (x < 0.5) ultraviolet photodetectors have been fabricated and characterized with cut-off wavelengths as short as 260 nm. Carrier lifetimes on the order of 10 milliseconds were estimated from frequency dependent measurements of the responsivity. reprint
 
590.  Long-Wavelength InAsSb Photoconductors Operated at Near Room Temperatures (200-300 K)
J.D. Kim, D. Wu, J. Wojkowski, J. Piotrowski, J. Xu, and M. Razeghi
Applied Physics Letters., 68 (1),-- January 1, 1996
Long-wavelength InAs1−xSbx photoconductors operated without cryogenic cooling are reported. The devices are based on p-InAs1−xSbx/p-InSb heterostructures grown on (100) semi-insulating GaAs substrates by low pressure metalorganic chemical vapor deposition (LP‐MOCVD). Photoreponse up to 14 μm has been obtained in a sample with x=0.77 at 300 K, which is in good agreement with the measured infrared absorption spectra. The corresponding effective lifetime of ≊0.14 ns at 300 K has been derived from stationary photoconductivity. The Johnson noise limited detectivity at λ=10.6 μm is estimated to be about 3.27×107 cm· Hz½/W at 300 K. reprint
 
591.  High-Temperature Reliability of Aluminum-free 980nm and 808nm Laser Diodes
J. Diaz, H. Yi, C. Jelen, S. Kim, S. Slivken, I. Eliashevich, M. Erdtmann, D. Wu, G. Lukas, and M. Razeghi
-- January 1, 1996
 
592.  New Infrared Materials and Detectors
M. Razeghi, J.D. Kim, S.J. Park, Y.H. Choi, D. Wu, E. Michel, J. Xu, and E. Bigan
-- January 1, 1996
 
593.  Background limited performance in p-doped quantum well intersubband photodetectors
J. Hoff, J. Piotrowski, E. Bigan, M. Razeghi, and G.J. Brown
-- January 1, 1996
 
594.  GaN Based Semiconductors for Future Optoelectronics
D. Walker, P. Kung, A. Saxler, X. Zhang, and M. Razeghi
-- January 1, 1996
 
595.  MOCVD Growth of Ga1-xInxAsyP1-y-GaAs Quantum Structures
M. Razeghi, J. Hoff, M. Erdtmann, S. Kim, D. Wu, E. Kaas, C. Jelen, S. Slivken, I. Eliashevich, J. Diaz, E. Bigan, G.J. Brown, S. Javadpour
-- January 1, 1996
 
596.  Semiconductor ultraviolet photodetectors
A. Rogalski and M. Razeghi
-- January 1, 1996
 
597.  Kinetics of photoconductivity in n-type GaN photodetector
P. Kung, X. Zhang, D. Walker, A. Saxler, J. Piotrowski, A. Rogalski, and M. Razeghi
Applied Physics Letters 67 (25)-- December 18, 1995
High-quality ultraviolet photoconductive detectors have been fabricated using GaN layers grown by low-pressure metalorganic chemical vapor deposition on (11⋅0) sapphire substrates. The spectral responsivity remained nearly constant for wavelengths from 200 to 365 nm and dropped sharply by almost three orders of magnitude for wavelengths longer than 365 nm. The kinetics of the photoconductivity have been studied by the measurements of the frequency‐dependent photoresponse and photoconductivity decay. Strongly sublinear response and excitation‐dependent response time have been observed even at relatively low excitation levels. This can be attributed to redistribution of the charge carriers with increased excitation level. reprint
 
598.  MOVPE Growth of High Electron Mobility AlGaN/GaN Heterostructures
J.M. Redwing, J.S. Flynn, M.A. Tischler, W. Mitchel, and A. Saxler
-- November 27, 1995
 
599.  The Microstructural Study of Aluminum Nitride Thin Films: Epitaxy on the Two Orientations of Sapphire and Texturing on Si
K. Dovidenko, S. Oktyabrsky, J. Narayan, and M. Razeghi
-- November 27, 1995
 
600.  Spectral response on GaN p-n junction photovoltaic structures
D. Walker, X. Zhang, P. Kung, A. Saxler, J. Xu and M. Razeghi
-- November 27, 1995
 

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