Numerical simulation of ZnSe/GaAs interface reflectance difference spectroscopy

A numerical method based on the matrices established by Yen [Optical Waves in Layered Media (Wiley, New York, 1988)] is developed to simulate the non-normal incidence reflectance difference spectroscopy (RDS) spectra of biaxial anisoctropic (ε_x≠ε_y≠ε_z) multilayer systems. The main features of me RDS spectra obtained from the biaxial anisotropic ZnSe/GaAs interface are reproduced by the numerical method. It has demonstrated that in the cases of near-normal incidence and when the anisotropy within the layer plane (in-plane anisotropy) is small (ε_x-ε_y≪ε_x) a RDS spectrum can be separated into two spectra, namely, the in-plane anisotropic spectrum and the off-plane anisotropic spectrum. The reflectance of the s wave and the p wave can be calculated separately when the in-plane principal axes are at certain orientations, making it possible to obtain the anisotropic dielectric tensor directly from the measured spectra.