Multiple cations interdiffusion in InGaAs/InAlAs quantum well structure and their optical gain properties

Multiple cations intermixed In _0.53Ga _0.47As/In _0.52Al _0.48As quantum well structures with 60 Å well width are investigated using the expanded form of Fick´s second law. For a small interdiffusion, i.e. 1 to 1.5 hrs, the subband separation between the lowest heavy and light hole states is at its greatest. This is a major contribution to the band structure and averaged density of states, thus enhancement in optical gain up to 40% is obtained. For a large interdiffusion, i.e. up to 6 hrs, a blue shift of the peak gain from 0.842 to 1.016 eV is observed.