Influence of SiO_2 and TiO_2 dielectric layers on the atomic intermixing of In_xGa_(1-x)As/InP quantum well structures

摘要

We have studied the influence of SiO_2 and TiO_2 dielectric layers on the atomic intermixing of In_xGa_(1-x)As/InP quantum well structures using the impurity-free vacancy disordering technique. Photoluminescence results revealed that an enhancement of interdiffusion was obtained when the samples were capped with SiO_2. Although TiO_2 layers were able to suppress the interdiffusion in the InGaAs/InP system, the suppression was not significant compared to the AlGaAs/GaAs system. Based on a fitting procedure that was deconvoluted from the photoluminescence spectra as well as a theoretical modeling, the electron-heavy hole and electron-light hole transitions were identified, and a ratio of the group Ⅴ to the group Ⅲ diffusion coefficients (k) was obtained. The k ratio of the InGaAs/InP samples capped with SiO_2 is relatively larger than that of samples capped with TiO_2 layers.