Showing papers by "W. Shan published in 2002"

Effects of the narrow band gap on the properties of InN

Abstract: Infrared reflection experiments were performed on wurtzite InN films with a range of free-electron concentrations grown by molecular-beam epitaxy. Measurements of the plasma edge frequencies were used to determine electron effective masses. The results show a pronounced increase in the electron effective mass with increasing electron concentration, indicating a nonparabolic conduction band in InN. We have also found a large Burstein-Moss shift of the fundamental band gap. The observed effects are quantitatively described by the kip interaction within the two-band Kane model of narrow-gap semiconductors.

Band-gap bowing effects in BxGa1-xAs alloys

Abstract: Author(s): Shan, W.; Walukiewicz, W.; Wu, J.; Yu, K.M.; Ager, J.W.; Li, S.X.; Haller, E.E.; Geisz, J.F.; Friedman, D.J.; Kurtz, S.R.

Band anticrossing effects in MgyZn1−yTe1−xSex alloys

Abstract: The electronic structures of MgyZn1−yTe1−xSex alloys were studied by optical absorption and photoluminescence techniques under applied hydrostatic pressure. In samples with both x and y≠0, the band gap exhibits a strongly nonlinear pressure dependence which is similar to the effects observed previously in ZnTe1−xSex and ZnTe1−xSx ternaries and that is well explained by the anticrossing interaction of the selenium localized electronic states with the conduction band of the matrix. In contrast, the pressure dependence of the band gap in MgyZn1−yTe (i.e., x=0) is not significantly changed in form from that of ZnTe; it is concluded that the effects of alloying MgTe with ZnTe can be well understood within the virtual crystal approximation.