Spectroscopic ellipsometric determination of the optical constants of chalcogenide films of the Ge-Sb-S-Te system

Abstract

Spectroscopic ellipsometric studies of GexSb 40-xS50Te10 (x10, 20, 27) and Ge 27Sb13S55Te5 films evaporated on glass substrates demonstrated the compositional dependence of the optical constants, namely, as the Ge fraction in the films is increased from 10 to 27, the values of the refractive index and extinction coefficient gradually decrease, while the optical band gap increases from 1.04 eV to 1.33 eV. © 2008 IOP Publishing Ltd.