Thickness and Compositional Dependant Optical Study of Pb_9Se_(71)Ge_(20-x)Sn_x (8 ≤ x ≤ 12) Glass

摘要

Thickness and compositional dependence of optical properties of Pb_9Se_(71)Ge_(20-x)Sn_x (8≤ x≤ 12) glass has been studied. Various optical constants such as refractive index, extinction coefficient and optical band gap have been determined by analyzing optical transmittance and reflectance data in the wavelength range of 200-3500 nm. Refractive index and extinction coefficient increase as Sn content increase in material. With the rise in thickness, there may be increase in grain size of the film and continuous random network simultaneously, result in reduced band gap. The isoelectronic substitutions of Ge by Sn in the glassy system also contribute to reduction in optical band gap of the material.