Effect of band parameters on interband optical absorption in quantum wire structure of low band gap Ⅲ-Ⅴ semiconductors

摘要

A generalized theory is presented to study the effect of band parameters on inter band optical absorption in quantum wire structure of Ⅲ-Ⅴ compound semiconductors considering the wave-vector (k) dependence of the optical transition matrix element (OME). The band structures of these low band gap semiconducting materials with sufficiently separated split-off valance band are frequently described by the three energy band model of Kane. This has been adopted to calculate the inter band optical absorption coefficient (IOAC) for a wide range of Ⅲ-Ⅴ compound semiconductors like, InAs, InSb, Hg_(1-x)Cd_x Te and In(1_x)Ga_xAs_yP(1_y) lattice matched to InP, having varied split-off energy band compared to their energy band gap. It has been found that IOAC for quantum wires (QWRs) increases in oscillatory manner with increasing incident photon energy and the positions of peaks of oscillation of the coefficient are more closely spaced in the three band model of Kane than those with parabolic energy band approximations reflecting the direct the influence of band energy constants. This effect of band parameters is better revealed from the study of light polarization dependence of the absorption coefficient.