Optical gain gradient under electric field on GaAsSb/InAs heterostructure

This article reports the change in band alignment and gradient of optical characteristics (i.e. gradient of optical gain and transition wavelength) of the type-II GaAsSb/InAs/AlSb W-shaped – heterostructure having double quantum wells (DQWs) under applied dc electric field. The quantum wells width was kept as ~ 20 nm. The range of applied electric field was kept from 20 kV/cm to 100 kV/cm. In results, it is found that for the applied variable electric field, the optical gain as well as optical wavelength both changes significantly. For the applied dc electric field up to 50 kV/cm, the gain gradient is found positive after that it becomes negative. The results are novel and claim the usage of such heterostructure as tunable light source with high optical gain.