RESIDUAL STRAINS AND DISORDER IN ZNSSE EPITAXIAL-FILMS ON GAAS

A new experimental and analytical method was demonstrated for the quantitative evaluation of disorder and strains in ZnSxSe1-x/GaAs heterostructures. The alloy disorder and the average size of ZnSe microclusters in epitaxial ZnSxSe1-x films were estimated from the linewidth of the ZnSe-like LO-phonon Raman signal. The linewidth of the GaAs LO-phonon Raman signals and the magnitude of photoacoustic signals were sensitive to strains near the interface due to the lattice mismatch between ZnSSe and GaAs. This technique provides microscopic understanding of the disorders and strains in lattice-mismatched semiconductor heterostructures.