Spectroscopic ellipsometry and photoluminescence investigation of Zn_(1-x-y)Be_xMg_ySe and Cd_(1-x-y)Be_xZn_ySe crystals

摘要

Optical and luminescence properties of the Bridgman-grown Cd_(1-x-y)Be_xZn_ySe and Zn_(1-x-y)Be_xMg_ySe crystals arc reported. Spectroscopic ellipsometry was employed for determination of spectral dependence of the complex dielectric function ε(E) in the photon energy range 0.75-6.5 eV. Below the ab-rnsorption edge the refractive indices n(E) of the alloys were modelled using a Sellmcier-type relation. The excitonic band-gap energies were estimated from the ellipsometric and photoluminescence measurements. Compositional effects in the ellipsometric and photoluminescence spectra are discussed.