In situ observation of strain-induced optical anisotropy of ZnSxSe1-x/GaAs(110) during molecular-beam epitaxy

In-plane optical anisotropy induced by biaxial strain of pseudomorphic ZnSx Se1-x layers grown on GaAs(110) is observed around the band-gap energy by r eflectance difference spectroscopy (RDS). The evolution of the strain-induc ed peaks with increasing film thickness is analyzed by the three-phase (sub strate-overlayer-ambient) model. The magnitude and shape of the peaks are, respectively, correlated with the strain and the film thickness. Dielectric -function anisotropies of the pseudomorphic overlayers an obtained using a decomposition method of RD spectra and their imaginary part have a sharp pe ak at fundamental-gap energy.