Publications by    
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751.  Finite-Size Scaling in the Dissipative Transport Regime Between Quantum Hall Plateaus
Razeghi M., S. Koch, R.J. Hang, K.V. Klitzing, K. Ploog
-- January 1, 1993
 
752.  Splitting of the Landau Level Coincidence: A Novel Phase Transition in Tilted Magnetic Fields
Razeghi M., S. Koch, R.J. Hang, K.V. Klitzing
-- January 1, 1993
 
753.  Growth of InSb/GaAs layers on YIG-coated GGG substrate
C. Jelen, S. Charriere, M. Razeghi, and V.J. Leppert
-- January 1, 1993
 
754.  High Power 0.98 μm GaInAs/GaAs/GaInP Multiple Quantum Well Laser
K. Mobarhan, M. Razeghi, G. Marquebielle and E. Vassilaki
Journal of Applied Physics 72 (9)-- November 1, 1992
We report the fabrication of high quality Ga0.8In0.2As/GaAs/Ga0.51In0.49P multiple quantum well laser emitting at 0.98 μm grown by low pressure metalorganic chemical vapor deposition. Continuous wave operation with output power of 500 mW per facet was achieved at room temperature for a broad area laser with 130 μm width and 300 μm cavity length. This is an unusually high value of output power for this wavelength laser in this material system. The differential quantum efficiency exceeded 75% with excellent homogeneity and uniformity. The characteristic temperature, T0 was in the range of 120–130 K. reprint
 
755.  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
 
756.  Optical Investigations of GaAs-GaInP Quantum Wells Grown on the GaAs, InP, and Si Substrates
H. Xiaoguang, M. Razeghi
Applied Physics Letters 61 (14)-- October 5, 1992
We report the first photoluminescence investigation of GaAs‐Ga0.51In0.49P lattice matched multiquantum wells grown by the low pressure metalorganic chemical vapor deposition simultaneously in the same run on GaAs, Si, and InP substrates. The sharp photoluminescence peaks indicate the high quality of the samples on three different substrates. The temperature dependence of the photoluminescence indicates that the intrinsic excitonic transitions dominate at low temperature and free‐carrier recombinations at room temperature. The photoluminescence peaks of the samples grown on Si and InP substrates shift about 15 meV from the corresponding peaks of the sample grown on the GaAs substrate. Two possible interpretations are provided for the observed energy shift. One is the diffusion of In along the dislocation threads from GaInP to GaAs and another is the localized strain induced by defects and In segregations. reprint
 
757.  Frontiers of Monolithic Integration of Semiconductor III-V Optoelectronic Devices with Si Technology
M. Razeghi, R. Sudharsanan, and J.C.C. Fan
-- August 1, 1992
 
758.  GaInAs/GaAs/GaInP Buried Ridge Structure Single Quantum Well Laser Emitting at 0.98 μm
K. Mobarhan, M. Razeghi and R. Blondeau
-- July 30, 1992
 
759.  Evaluation of the Band Offsets of GaAs-GaInP Multilayers by Electroreflectance
Razeghi M., D. Yang, J.W. Garland, Z. Zhang, D. Xue
SPIE Proceedings, Vol. 1676, pp. 130-- January 1, 1992
We report the first band offset measurement of GaAs/Ga0.51In0.49P multiquantum wells and superlattices by electrolyte electroreflectance spectroscopy. The conduction and valence band discontinuities (Delta) Ec equals 159 ± 4 meV and (Delta) Ev equals 388 ± 6 meV have been measured. The values found for the conduction band, heavy-hole and light-hole masses in the GaInP barriers and GaAs wells and for the split-off well mass are in excellent agreement with the literature. The intraband, intersubband transition energies, which are important for III - V infrared detection devices, also were directly measured. reprint
 
760.  Caracterisation optique des semiconducteurs III-V par ellipsometrie et reflectance differentielle spectroscopique
Acher O., Omnes F., Razeghi M., Drevillion B.
-- September 1, 1991
 
761.  Incorporation of Impurities in GaAs Grown by MOCVD
Razeghi M., and M.A. di Forte-Poisson
-- September 1, 1991
 
762.  Etude du dopage de type n et p des materiaux GaAs et GaInP
Omnes F., Defour M., Razeghi M.
-- September 1, 1991
 
763.  GaAs-GaInP Multipayers for High Performance Electronic Devices
Omnes F., and Razeghi M.
-- September 1, 1991
 
764.  A Review of the Band Offsets Measurements in the GaAs/Ga0.49In0.51P System
Omnes F., and Razeghi M.
-- September 1, 1991
 
765.  Optical Investigations of GaAs-GaInP Quantum Wells and Superlattices Grown by Metalorganic Chemical Vapor Deposition
Omnes F., and Razeghi M.
Applied Physics Letters 59 (9), p. 1034-- May 28, 1991
Recent experimental results on the photoluminescence and photoluminescence excitation of GaAs‐Ga0.51In0.49P lattice‐matched quantum wells and superlattices are discussed. The full width at half maximum of a 10‐period GaAs‐GaInP superlattice with Lz=90 Å and LB=100 Å is 4 meV at 4 K. The photoluminescence excitation exhibits very sharp peaks attributed to the electron to light‐hole and electron to heavy‐hole transitions. The GaInP‐GaAs interface suffers from memory effect of In, rather than P or As elements. reprint
 
766.  Defects in Organometallic Vapor-Phase Epitaxy-Grown GaInP Layers
Feng S.L., Bourgoin J.C., Omnes F., and Razeghi M.
Applied Physics Letters 59 (8), p. 941-- May 28, 1991
Non-intentionally doped metalorganic vapor‐phase epitaxy Ga1−x InxP layers, having an alloy composition (x = 0.49) corresponding to a lattice matched to GaAs, grown by metalorganic chemical vapor deposition, have been studied by capacitance‐voltage and deep-level transient spectroscopy techniques. They are found to exhibit a free‐carrier concentration at room temperature of the order of 1015 cm−3. Two electron traps have been detected. The first one, at 75 meV below the conduction band, is in small concentration (∼1013 cm−3) while the other, at about 0.9 eV and emitting electrons above room temperature, has a concentration in the range 1014–1015 cm−3. reprint
 
767.  InGaAs(P)/InP MQW Mixing by Zn Diffusion Ge and S Implantation for Optoelectronic Applications,
Julien F.H., Bradley M., Rao E.V.K., Razeghi M., Goldstein L.
-- November 30, 1990
 
768.  Defects in High Purity GaAs Grown by Low Pressure Metalorganic Chemical Vapor Deposition
Feng S.L., Bourgoin J.C., and Razeghi M.
-- November 30, 1990
 
769.  Recent Advances in MOCVD Growth of GaAs/GaInP System for OEICs Applications
Razeghi M.
-- November 30, 1990
 
770.  High Power, Room Temperature, Terahertz sources and frequency comb based on Difference frequency generation at CQDf
Professor Manijeh Razeghi
-- November 30, 1999
Quantum cascade laser (QCL) is a semiconductor laser based on intersubband transitions [1]. After near three decades of development, it has become the most important coherent light source in mid-infrared (mid-IR) and terahertz (THz) ranges. Many other application technologies, like spectroscopies capable of molecular absorption fingerprint measurement, medical imaging capable of in-depth observation and analysis of diseased tissues and organs, and free-space communications targeting faster, longer distance communications are benefiting from the rapid advancement of QCL technologies [2]. High performance in power, efficiency and spectral range are of fundamentally importance to the above QCL applications. Center for Quantum Device (CQD) in Northwestern University has been focused on QCL technology research and development in the past years [3-6]. Constant improvement in the structure design, material quality, and fabrication technologies, as well as the nonlinear effects for THz and frequency comb has been achieved. Previously, we has demonstrated high power room temperature continuous wave (CW) operation across a wide range of wavelength from 3.0 μm [7] to 145.6 μm [8], and the most powerful QCLs in room temperature CW operation with the highest WPE of 21% at 4.9 μm[9] and the highest power of 8.2 W at 8.1 μm [10]. In this paper, we present some of our recent breakthroughs in QCLs, discussed in detail in the following sections, on high power and high efficiency CW QCLs, high power room temperature THz sources based on DFG-QCL, room temperature THz frequency comb, and injection locking of high-power QCLs. The demonstrated QCLs are holding great promises for next generation mid-infrared spectroscopy and sensing.
 

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