Publications by    
Page 1  (12 Items)

1.  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
 
2.  Exploration of entire range of III-V semiconductors and their device applications
M. Razeghi, Y.H. Choi, X. He, and C.J. Sun
-- January 1, 1995
 
3.  A detailed analysis of carrier transport in InAs0.3Sb0.7 layers grown on GaAs substrates by metalorganic chemical vapor deposition
C. Besikci, Y.H. Choi, G. Labeyrie, E. Bigan and M. Razeghi with J.B. Cohen, J. Carsello, and V.P. Dravid
Journal of Applied Physics 76 (10)-- November 15, 1994
InAs0.3Sb0.7 layers with mirrorlike morphology have been grown on GaAs substrates by low‐pressure metalorganic chemical vapor deposition. A room‐temperature electron Hall mobility of 2×104 cm²/V· s has been obtained for a 2 μm thick layer. Low‐temperature resistivity of the layers depended on TMIn flow rate and layer thickness. Hall mobility decreased monotonically with decreasing temperature below 300 K. A 77 K conductivity profile has shown an anomalous increase in the sample conductivity with decreasing thickness except in the near vicinity of the heterointerface. In order to interpret the experimental data, the effects of different scattering mechanisms on carrier mobility have been calculated, and the influences of the lattice mismatch and surface conduction on the Hall measurements have been investigated by applying a three‐layer Hall‐effect model. Experimental and theoretical results suggest that the combined effects of the dislocations generated by the large lattice mismatch and strong surface inversion may lead to deceptive Hall measurements by reflecting typical n‐type behavior for a p‐type sample, and the measured carrier concentration may considerably be affected by the surface conduction up to near room temperature. A quantitative analysis of dislocation scattering has shown significant degradation in electron mobility for dislocation densities above 107 cm−2. The effects of dislocation scattering on hole mobility have been found to be less severe. It has also been observed that there is a critical epilayer thickness (∼1 μm) below which the surface electron mobility is limited by dislocation scattering. reprint
 
4.  Characterization of InTlSb/InSb Grown by Low Pressure Metalorganic Chemical Vapor Deposition on GaAs Substrat
Y.H. Choi, P. Staveteig, E. Bigan, and M. Razeghi
Journal of Applied Physics 75 (6)-- March 15, 1994
Optical properties of InTlSb, a new long wavelength infrared material, are investigated. InTlSb/InSb epilayers grown by low‐pressure metal‐organic chemical vapor deposition on semi‐insulating GaAs substrates were characterized using Auger electron spectroscopy and Fourier transform infrared spectroscopy. Auger electron spectra confirm the presence of thallium. Transmission measurements at 77 K indicate an absorption shift from 5.5 μm for InSb up to 8 μm for InTlSb that is confirmed by photoconductivity measurements. reprint
 
5.  Photoconductance measurements on InTlSb/InSb/GaAs grown by low-pressure metalorganic chemical vapor deposition
P.T. Staveteig, Y.H. Choi, G. Labeyrie, E. Bigan, and M. Razeghi
Applied Physics Letters 64 (4)-- January 24, 1994
We report infrared photoconductors based on InTlSb/InSb grown by low‐pressure metalorganic chemical vapor deposition on semi-insulating GaAs substrates. The photoresponse spectrum extends up to 8 μm at 77 K. The absolute magnitude of the photoresponse is measured as a function of bias. The specific detectivity is estimated to be 3×108 Hz½·cm·W-1 at 7 μm wavelength. reprint
 
6.  InTlSb alloys for infrared detection
E. Bigan, Y.H. Choi, G. Labeyrie, and M. Razeghi
Proceedings, SPIE Nonlinear Optics for High-Speed Electronics and Optical Frequency Conversion, Vol. 2145-- January 24, 1994
InTISb alloys have been grown by low-pressure metalorganic chemical vapor deposition, and characterized. Photoconductors exhibit a cutoff wavelength that can be tailored from 5.5 μm up to 9 μm by varying the thallium content. Experimental observations suggest that this can be further extended by increasing the thallium content. An InTISb photoconductor having a 9 μm cutoff wavelength exhibited a D* of 109 cm·Hz½·W-1 at 7 μm operating wavelength. reprint
 
7.  The Effects of V/III Ratio on Optical, Electrical and Structural Properties of InAs0.3Sb0.7Grown by LP-MOCVD
Y.H. Choi, G. Labeyrie, P.T. Staveteig, E. Bigan, and M. Razeghi
-- October 15, 1993
 
8.  In1- x TlxSb for Long-Wavelength Infrared Photodetectors
Y.H. Choi, P.T. Staveteig, E. Bigan, and M. Razeghi
-- October 10, 1993
 
9.  Transport properties in n-type InSb films grown by metalorganic chemical vapor deposition
S.N. Song, J.B. Ketterson, Y.H. Choi, R. Sudharsanan, and M. Razeghi
Applied Physics Letters 63 (7)-- August 16, 1993
We have measured the temperature and magnetic field dependence of the Hall mobility and transverse magnetoresistance in n-type InSb films epitaxially grown on GaAs substrates by metalorganic chemical vapor deposition. The films show a giant magnetoresistance: e.g., at 240 K the resistivity increases over 20 times at a magnetic field of 5 T; the low field coefficient of resistivity at 77 K is as high as 47.5 μ·Ω· cm/G. The Hall mobility decreases with magnetic field and saturates at higher fields. By taking the interface carrier transport into account, the observed field dependence of the Hall mobility and magnetoresistance may be understood based on a two-layer model. reprint
 
10.  Growth of In1-xTlxSb, a New Infrared Material, by Low-Pressure Metalorganic Chemical Vapor Deposition
Y.H. Choi, R. Sudharsanan, C, Besikci, and M. Razeghi
Applied Physics Letters 63 (3)-- July 19, 1993
We report the growth of In1-xTlxSb, a new III-V alloy for long-wavelength infrared detector applications, by low-pressure metalorganic chemical vapor deposition. In1-xTlxSb with good surface morphology was obtained on both GaAs and InSb substrates at a growth temperature of 455 °C. X-ray diffraction measurements showed resolved peaks of In1-xTlxSb and InSb films. Infrared absorption spectrum of In1-xTlxSb showed a shift toward lower energies compared to InSb spectrum. Hall mobility data on In1-xTlxSb/InSb/GaAs structure showed enhanced mobility at low temperatures compared to InSb/GaAs structure. reprint
 
11.  Anomalous Hall Effect in InSb Layers Grown by MOCVD on GaAs Substrates
C. Besikci, Y.H. Choi, R. Sudharsanan, and M. Razeghi
Journal of Applied Physics 73 (10)-- May 15, 1993
InSb epitaxial layers have been grown on GaAs substrates by low‐pressure metalorganic chemical vapor deposition. A 3.15 μm thick film yielded an x‐ray full width at half maximum of 171 arcsec. A Hall mobility of 76  200 cm²/V· s at 240 K and a full width at half maximum of 174 arcsec have been measured for a 4.85 μm thick epilayer. Measured Hall data have shown anomalous behavior. A decrease in Hall mobility with decreasing temperature has been observed and room‐temperature Hall mobility has increased with thickness. In order to explain the anomalous Hall data, and the thickness dependence of the measured parameters, the Hall coefficient and Hall mobility have been simulated using a three‐layer model including a surface layer, a bulklike layer, and an interface layer with a high density of defects. Theoretical analysis has shown that anomalous behavior can be attributed to donor-like defects caused by the large lattice mismatch and to a surface layer which dominates the transport in the material at low temperatures.   reprint
 
12.  High Quality InSb Epitaxial Film Grown by Low Pressure Metalorganic Chemical Vapor Deposition
Y.H. Choi, R. Sudharsanan, C. Besikci, E. Bigan, and M. Razeghi
-- November 1, 1992
 

Page 1  (12 Items)