Optical investigations of tin and zinc oxides as TCOs films

Transparent conducting oxides (TCOs) are an integral part of modern optoelectronics such as flat panel displays, solar cells and infrared reflection glasses. Tin-zinc oxides (ZTO) films show n-type electrical conductivity and high visible transmittance. In recent years Zn-Sn-O films have attracted much attention as new materials for transparent conducting oxides (TCOs) and amorphous oxide semiconductor films (AOSs). In the present work Zn1-xSnxO2-x (where x=0; 0.025; 0.975; 1) films have been obtained by dip coating sol-gel route on silicon and glass substrates. The as-prepared and thermally treated films for one hour at 500 degrees C were characterized by appropriate methods. X-ray diffraction was used for structure analysis of the films. The surface topography of the films was investigated by atomic force microscopy (AFM). The optical constants (refractive index and extinction coefficient) were calculated from Spectroscopic Ellipsometry (SE) data using Cauchy Model. Fluorescence emission was observed in the case of studied films excepting tin dioxide. The structure, morphology and optical properties of the obtained films depend on the composition, number of deposition and thermal treatment temperature.