Study of SnO2 Thin Film Deposited on Soda-lime Glass Using the Spray Pyrolysis Coating Method

Abstract

In this work, we present the influence of the substrate temperature on the optical and mechanical properties of tin oxide thin film deposited on soda-lime glass by using the spray pyrolysis method. The film is deposited at various substrate temperatures ranging from 300 to 500° C using steps of 50° C. The structure of the film is investigated by X-ray diffraction (XRD). The results showed that at 300° C the film presents an amorphous structure. While at higher substrate temperatures, the structure becomes polycrystalline with preferential growth direction (200). The formation of tin dioxide (SnO2) is achieved at 500° C. Besides, the variation of the transmittance in function of the wavelength in the region (300–850 nm) shows a wavy behavior between 300 and 500 nm and then a tendency towards a constant level. The transmittance level varies with the substrate temperature. It passes from 75% at 300° C to 91% at 500° C. The samples are also mechanically characterized by using Vickers indentation technique which allows to obtain the hardness and the fracture toughness (KIC). The results show that the hardness variation decreases linearly in function of the applied load in the used loading range (0.2 – 1.6 N). The lines level increases with the substrate temperature. The hardness passes from 5.4 GPa for the as received state to approximately 7 GPa for samples treated at 500° C. The fracture toughness decreases linearly in function of the applied load. The KIC variation lines for different temperature tend towards the same value (0.77 MPa√m) at P = 1.6 N.