Properties of AIGaAsSb–GaSb heterojunction injection lasers in the 1.4–1.8<i>μ</i>wavelength range

Abstract

The characteristics of heterostructures and the main radiative properties of infrared (1.4–1.8 μ) heterojunction lasers using quaternary solid solutions of AlGaAsSb, grown by liquid-phase epitaxy of GaSb substrates, are presented. A threshold current density of 2–4 kA/cm2 was obtained in heterojunction injection lasers at 300°K and estimates were made of the waveguide effect and the optimal thickness of the active layer. It was found that the relative discontinuity of the refractive index at the interfaces of the active layer was approximately 5% for a 25% reduction in the Al concentration from the wide- to narrow-gap layers of the heterostnicture. Continuous-wave laser action at 77°K was obtained in the 1.40-1.57 μ wavelength range.