Calculation of Valence Band Structure and Band Dispersion in Indium containing III-V Bismides by k.p method

Valence band anticrossing (VBAC) model has been used to explain the strong reduction in band gap as well as the increase in spin-orbit splitting energy with increasing bismuth incorporation in InAs1-xBix, InSb1-xBix and InP1-xBix. This effect is shown to be due to the restructuring of the valence band as a result of the anticrossing interaction of the extended states of the valence band of the host semiconductor with the Bi related impurity states. The anticrossing interaction causes the splitting of the light hole (LH), heavy hole (HH) and spin-orbit split-off (SO) bands into E+ and E sub bands. The upward movement of the LH/HH and SO E+ energy level is responsible for the reduction in bandgap and increase in spin-orbit splitting energy in bismides. The calculated values of the band gap reduction show good agreement with available experimental results. Band dispersion relations for these bismides in the Lambda, Delta, and Sigma directions are also calculated using the k.p method. (C) 2015 Elsevier B.V. All rights reserved.