The steady state hole transport properties of GaSb were investigated by the Ensemble Monte Carlo method (EMC). In our model we taken in to account heavy and light hole valence bands, and the following scattering mechanisms: inelastic acoustic phonon; polar optical phonon; nonpolar optical; ionized impurity. The theoretical calculations are compared with available experimental results for the GaSb hole mobility shown good agreement with temperatures from 90K up to 300K.

We report optical and structural characterizations of InAs quantum dot superlattices grown by molecular beam epitaxy on GaAs (001). Cross-sectional electron microscopy imaging reveals ~ 20 nm diameter InAs islands well aligned along the growth direction. Low temperature photoluminescence spectra exhibit a clear redshift with decreasing island vertical separation, as a result of electronic coupling between stacked dots, given that the larger shift is obtained for 70 Å spacing. At high excitation power, the photoluminescence spectra show a doublet structure corresponding to coupled and uncoupled quantum dot states. The temperature dependence of the photoluminescence indicates that thermionic emission activation energy is much lower than the estimated barrier height. Such a difference is explained by the presence of non-radiative recombination centers due to strain relaxation and In segregation.