Electrical, structural and optical properties of SnO 2:F thin films: Effect of the substrate temperature

Abstract

SnO 2:F thin films have been deposited from stannic chloride solution by simple and cost effective chemical spray pyrolysis technique onto glass substrates at different substrate temperatures. The as-deposited films were characterized by X-ray diffraction (XRD), SEM, optical and electrical characterization techniques. XRD analysis showed that, at lower substrate temperature; amorphous films have been obtained, while at higher temperatures ( T > 450 °C); crystalline SnO 2:F films with preferential growth along (2 0 0) plane have been observed. The average transmission in the visible region has been found to vary from 60% to 87% depending upon the substrate temperature. In the visible region of the spectrum, the transmission is very high (high enough to observe interference). For films prepared at 475 °C, relatively higher transmittance of about 87% at 850 nm has been observed. A thickness was found to vary from 440 nm to 740 nm with substrate temperature. The direct optical band gap energy for the SnO 2:F thin film is found to be 4.15 eV. The films deposited at 475 °C substrate temperature were found to have relatively lower resistivity of 3.91 × 10 −4 Ω cm. Hall Effect studies reveal that the films exhibit n-type conductivity.