The structural, electrical, and optical properties of SnO2 films prepared by reactive magnetron sputtering: Influence of substrate temperature and O2 flow rate

Abstract

The electrical and optical properties of SnO2 films prepared by sputtering are closely related to the substrate temperature and O2 flow rate, but the effect of these two parameters is not clearly clarified in previous investigations. In this study, the SnO2 films were deposited on glass substrate by reactive RF magnetron sputtering using Sn target at substrate temperature of room temperature (RT), 150 and 300 °C. At each substrate temperature, the structural, electrical and optical properties of the films were investigated as a function of O2 flow rate. By exposing typical films in damp-heat (DH) environment (85% relative humidity and 85 °C), the stability of electrical properties of the films was investigated. The results indicate that the SnO2 films with better transparent conductive properties can be obtained in an optimized O2 flow rate range at each substrate temperature. Compared with the crystalline films deposited at 150 and 300 °C, the amorphous films deposited at RT can achieve better transparent conductive properties (resistivity of 3.65 × 10−3 Ω cm and transmittance of 81.50% can be obtain simultaneously). However, the electrical properties of the films deposited at RT obviously degrade after DH exposure over one month. Besides, the analyses of photoluminescence (PL) spectra confirm that oxygen vacancy (VO) concentration plays a vital role in conductive properties of the films.