Effect of nonparabolicity of the electron and light-hole energy spectrum on the optical properties of heterostructures with deep AlSb/InAs$_{0.86}$Sb$_{0.14}$/AlSb quantum wells

The optical characteristics of heterostructures with deep quantum wells are studied using the AlSb/InAs$_{0.86}$Sb$_{0.14}$/AlSb structure within the framework of the four-band Kane model with regard to the nonparabolicity of the carrier energy spectrum. It is demonstrated that consideration of the nonparabolicity increases the number of size-quantization levels in the conduction band. At a quantum-well width of 100 $\mathring{\mathrm{A}}$, the investigated heterostructure contains three size-quantization levels within the parabolic model and six levels within the Kane model. This is due to the fact that the effective mass of high-energy electrons is found to be larger than the mass of electrons at the bottom of the conduction band by a factor of four. It is shown that account for the nonparabolicity only slightly affects the overlap integral for the $s$ and $p$ states, but significantly increases the density of states in the conduction band, which causes considerable growth in the radiation-absorption coefficient.