Destruction mechanism of III-V compound quantum well structures due to impurity diffusion

Abstract

Recent experiments have shown that quantum well structures grown on a GaAs substrate can be destroyed by dopant diffusion. It is observed that existing models proposed to explain the phenomena are not in accordance with most available experimental results. We propose an alternative mechanism to explain the quantum well destruction phenomenon. The mechanism is based on the effect of the Fermi level on the concentrations of charged point defects which contribute to diffusion processes. This conceptually simple mechanism is consistent with most available experimental results on a qualitative basis. In this mechanism, the doping level and the doping type (p or n) are of primary importance, and not some other detailed atomistic nature of the dopant species. Furthermore, it is the presence of the dopant that is important, and not its motion, i.e., its diffusion.