Infrared reflectance spectra of Sb-doped SnO2 ceramics

Abstract

Infrared specular reflectance spectra of Sn_{1 –x}Sb_xO₂ ceramics have been measured over a range of bulk doping levels extending up to x= 0.03 At low doping levels conduction electrons screen out coupling of the infrared radiation to bulk phonon modes in a way expected from a model in which reflectivity is calculated from the bulk dielectric function. However, at higher doping levels a reflectivity minimum develops at ca. 800 cm^–1. This is interpreted in terms of a model where a surface layer with low carrier concentration sits on top of an undepleted bulk.