Investigation of Electronic and Optical Properties of GaSbBi/GaAs Type-II Quantum Wells Using 14-Band k · p Hamiltonian
In order to investigate the electronic and optical properties of GaSbBi/GaAs type-II quantum well (QW) system, the well-established 8-band k · p Hamiltonian has been extended to a 14-band matrix. Incorporated dilute Bi in GaSb perturbs the valence and conduction bands of the host material, which leads to a reduction in band gap by about 40 meV/%Bi and an increase in spin-orbit splitting (SO) energy by ~21 meV/%Bi. In case of bulk GaSb0.987Bi0.013, the anticrossing interaction between Bi resonant states and host atom reduces the bandgap (51 meV) and enhance the SO energy (27 meV) of GaSb. A compressive strain of 7.3% perceived in GaSbBi/GaAs QW leads to a substantial increment in the band gap and SO energy to 1.12 eV and 1.217 eV respectively. Better confinement of carriers have been achieved owing to suitable tuning of valence band (VB) and conduction band (CB) offsets, which indeed assist to achieve an optical gain as high as 70/m−1 near the 2.2 µm mid-infrared window for a Type-II QW system.