Study of quantum well intermixing caused by grown-in defects

We show that the degree of thermally induced quantum well intermixing is dependent on the growth quality of epitaxial layer structures. Two different undoped quantum well/barrier structures are studied: an InGaAs/InGaAsP 1.5 mu m laser-like structure, and an InGaAs/InP structure. In both cases, the temperature of growth of one or more layers is altered and results compared with a control wafer. Wafers with material grown at the lower temperature display blueshifts of up to 80 meV in the QW emission energy during the early stages of rapid thermal annealing. Wafers grown at temperatures that are more standard exhibit excellent stability. We examine shifts of both the heavy hole and light hole transitions as a function of intermixing via transmission measurements, and conclude that interdiffusion occurs primarily on the group V sublattice. (C) 2000 American Institute of Physics. [S0021-8979(00)04417-0].