Publications by    
Page 1  (4 Items)

1.  Exciton localization in group-III nitride quantum wells
V.I. Litvinov and M. Razeghi
Physical Review B 59 (15)-- May 15, 1999
Exciton density of states broadened by compositional disorder in the group-III nitride quantum well is calculated. The excitonic photoluminescence linewidth is estimated and related to the material parameters of the alloy for two limiting cases of two-dimensional (2D) and three-dimensional excitons in the quantum well. It is shown that the effect of the compositional fluctuations depends on dimensionality of the exciton: the 2D excitons are more sensitive to the inhomogeneities than 3D ones. The broad near-band-gap energy states distribution for quasi-two-dimensional excitons is consistent with the experimental evidence of the spontaneous and stimulated emissions from excitonic states localized on compositional fluctuations. reprint
 
2.  Relaxation kinetics in quantum cascade laser
S. Slivken, V. Litvinov, M. Razeghi, and J.R. Meyer
Journal of Applied Physics 85 (2)-- January 15, 1999
Relaxation kinetics in a quantum cascade intersubband laser are investigated. Distribution functions and gain spectra of a three-subband double-quantum-well active region are obtained as a function of temperature and injection current. The potentially important role of the nonequilibrium phonons at lasing threshold is shown and discussed in details. It is shown that the threshold current is strongly dependent of the power dissipated in the active region in steady state. The numerical calculations for an 8.5 μm laser illustrate the general issues of relaxation kinetics in quantum cascade lasers. Temperature dependence of the threshold current is obtained in a good agreement with the experiments. reprint
 
3.  Interface-induced Suppression of the Auger Recombination in Type-II InAs/GaSb Superlattices
H. Mohseni, V.I. Litvinov and M. Razeghi
Physical Review B 58 (23)-- December 15, 1998
The temperature dependence of the nonequilibrium carriers lifetime has been deduced from the measurement of the photocurrent response in InAs/GaSb superlattices. Based on the temperature dependence of the responsivity and modeling of the transport parameters we have found that the carrier lifetime weakly depends on temperature in the high-temperature region. This indicates the temperature dependence of the Auger recombination rate with no threshold that differs it from that in the bulk material and can be attributed to the interface-induced suppression of the Auger recombination in thin quantum wells. reprint
 
4.  Relaxation kinetics in mid-infrared quantum cascade lasers
S. Slivken, V.I. Litvinov, M. Razeghi, and J.R. Meyer
-- December 1, 1998
 

Page 1  (4 Items)