Optical Gain in Type-II InAsN/GaSb Strained Quantum Wells Laser Diodes and Its Pressure Dependence

Abstract

Theoretical calculations of the hydrostatic pressure influence on the electronic band structure and the optical gain of N-containing InAs0.98N0.02/GaSb quantum wells laser diodes are presented. A ${\mathbf {k}}\cdot {\mathbf {p}}$ model, taking into account, the p-like valence band, the s-like and p-like conduction band, and the nitrogen resonant level is introduced. We have used a unitary transformation that block diagonalizes the $16\times16$ Hamiltonian into two $8\times8$ blocks that are real symmetric in the finite difference formulation. Numerical results have been determined over a pressure range from 0 to 30 kbar. It has been shown that the hydrostatic pressure changes the electronic band structure and as a result the optical gain decreases with the hydrostatic pressure by about 80% and 50% for [111] and [001] growth directions, respectively for transverse electric modes. Hence, the emission spectrum is shifted to shorter wavelength (i.e., for [111] direction, from $2.65~\mu \text{m}$ to $1.16~\mu \text{m}$ ).