Effects of biaxial strain on the intervalence‐band absorption spectra of InGaAs/InP systems

Abstract

The effects of biaxial strain on the intervalence‐band absorption spectra of p‐doped InGaAs/InP bulk layers are investigated. The study is performed by calculating and comparing the absorption coefficients corresponding to the direct transitions between the heavy and light hole bands, between the heavy hole and split‐off bands, and between the split‐off and light hole bands in both the lattice matched and the strained layers. The valence‐band structures of these layers are neither isotropic nor parabolic and hence the k⋅p approach is utilized to calculate the band structures and their corresponding wave functions. The quantities are then invoked in the calculation of the (joint) density of states, the Fermi energy, and the momentum matrix element, which are needed in the evaluation of the intervalence‐band absorption coefficients. These calculated results show that the intervalence‐band absorption coefficients depend on the strain in the layer. The dependence is determined by the bands involved in the intervalence transition, the polarization of the incident light, and the type of the strain (compressive or tensile). © 1995 American Institute of Physics.