Modelling of GaAsSb/InAs type-II QW heterostructure and simulation of its optical gain characteristics under (100), (001) and (110) directional pressure

Abstract

A multi band (particularly, six band) k. p approach has been adopted for modelling the GaAsSb/InAs/AlSb W-shaped quantum well (QW)-heterostructure (a type-II with broken bandgap band alignment) and simulation of behaviour of optical gain characteristics under uni- and bi-axial pressures. The motivation behind designing such QW heterostructure is its high optical gain in MIR (mid infrared region) with noteworthy tuneable optical characteristics. The tuneable characteristics under uni-axial (100) and (001) pressure and bi-axial (110) pressure have been studied through the simplification of a multiband band k. p Hamiltonian. For all the directional pressures, the pressure range was fixed from 1 GPa to 3 GPa (with the interval of 0.5 GPa). For the (100) directional pressure, a significant increase in the gain (from 3570 to 7800/cm) was noted showing the red shifted wavelength with increasing order of pressure; while (001) directed pressure has caused to reduce the gain (3550–1158/cm) with red shifted wavelength. The (110) directed pressure has also caused to enhance the gain considerably (2550–7597/cm) with change in wavelength towards high wavelength. The study of gain characteristics was performed considering 1.5 × 1012 cm−2 2-D charge carrier density, which proves the tunability of the designed heterostructure in various tuneable optoelectronic devices.