Dependence of Al-Ga interdiffusion in AlGaAs on stoichiometry between Ga-rich and As-rich solidus limits

The effect of stoichiometry on the Al-Ga interdiffusion of undoped AlGaAs/GaAs multiple quantum wells is investigated over the full composition range of the GaAs solidus. The 2 orders of magnitude increase observed in the interdiffusion coefficient suggests that interdiffusion in an intrinsic crystal is mediated predominantly by column III vacancies throughout the whole solidus range. In addition, we observe that the photoluminescence intensity of the Ga-rich crystal is more than 3 orders of magnitude stronger than that of the As-rich crystal.