Optical gain enhancement and wavefunction confinement tuning in AlSb/InGaAsP/GaAsSb heterostructures

Abstract

The results from self-consistent $k\cdot p$ computation of optical gain characteristics of AlSb/InGaAsP/GaAsSb type-II ultra-thin quantum-well heterostructures show a marked improvement in optical gain as compared to the InGaAsP/GaAsSb type-II ultra-thin quantum well heterostructures. The AlSb/InGaAsP/GaAsSb type-II ultra-thin quantum well heterostructures were designed to obtain enhanced optical gain as compared to InGaAsP/GaAsSb type-II quantum well heterostructures. An improvement in optical gain of 948 ${cm}^{-1}$ and a shift in peak energy of 0.03 eV is attributed to interband resonant tunnelling effect and the band alignment due to the presence of GaAsSb layer. Also, a narrower optical gain spectrum is observed in $\mathrm {AlSb/}{\mathrm {In}}_{{0.5}}{\mathrm {Ga}}_{{0.5}}{\mathrm {As}}_{{0.8}}\mathrm {P}_{{0.2}}\mathrm {/Ga}{\mathrm {As}}_{{0.5}}{\mathrm {Sb}}_{{0.5}}$ QW heterostructure as compared to the ${\mathrm {In}}_{{0.5}}{\mathrm {Ga}}_{{0.5}}{\mathrm {As}}_{{0.8}}\mathrm {P}_{{0.2}}\mathrm {/Ga}{\mathrm {As}}_{{0.5}}{\mathrm {Sb}}_{{0.5}}$ QW heterostructures. Furthermore, the effect of variation in well width has been studied at AlSb layer thickness 1 nm for optical gain enhancement and wavefunction confinement where the resonant tunnelling effect is observed.

Graphic Abstract

Fig. Optical gain in ${AlSb/}{{In}}_{{0.5}}{{Ga}}_{{0.5}}{{As}}_{{0.8}}{P}_{{0.2}}{/Ga}{{As}}_{{0.5}}{{Sb}}_{{0.5}}$ heterostructures