Effect of annealing-induced interdiffusion on the electronic structure of mid infrared emitting GaInAsSb/AlGaInAsSb quantum wells

There has been investigated the effect of post-growth-annealing-induced interdiffusion process, and hence interface intermixing, on the electronic structure of Ga_0.35In_0.65As_0.32Sb _0.68/Al_0.25Ga_0.50In_0.25As _0.24Sb_0.76 single quantum well designed to emit light in the range of about 3 μm. The band structure and optical transitions have been calculated based on the single band effective mass model and Fick's interdiffusion law. The calculation results are consistent with the experimentally observed transitions obtained by employing modulation spectroscopy. Our studies indicate that the intermixing processes in this kind of quantum wells are predominantly induced by the interdiffusion of group III atoms. The derived effective diffusion coefficient has been estimated to be of the order of 10^-21 m² s^-1 for 480 °C annealing temperature.