Comparative study of optical characteristics of SQW and DQWs InGaAs/GaAsSb/AlAsSb based compressively strained heterostructures

Abstract

InP-based InGaAs/GaAsSb/AlAsSb type-II single quantum well (SQW) and double quantum wells (DQWs) heterostructures are compared on the basis of matrix elements, energy dispersion curves, optical gain, and transition energy. The effect on optical gain due to applied external strain and the influence of In-mole fraction and Sb-mole fraction on momentum matrix element and transition wavelength have also been compared between SQW and DQWs heterostructures. The simulation results show that the transition wavelength is located in the short wavelength infrared region (SWIR). SWIR imaging has various applications such as solar cell inspection, surveillance, electronic board inspection, identification and sorting, and more. For the proposed design, a total optical gain of 7450 cm−1 and 13,681 cm−1 is obtained at 0.75 eV and 0.77 eV transition energies for the SQW and DQWs heterostructures. For 1.5 nm QW thickness and 3x1012 cm−2 injected carrier density at 300 K, the transition wavelength increases from 1.67 μm to 1.82 μm and 1.60 μm–1.77 μm for SQW and DQWs heterostructure, respectively on increasing the mole fraction value of In from 0.5 to 0.8 and when the mole fraction value of Sb increases from 0.5 to 0.8, the transition wavelength increases from 1.69 μm to 1.87 μm and 1.62 μm–1.79 μm for SQW and DQWs heterostructure, respectively.