Investigation of the effect of temperature on the structural, optical, electrical, and self-cleaning properties of ITO thin films

Abstract

Transparent conductive tin-doped indium oxide (In2O3:Sn, ITO) thin films have been deposited onto glass substrate at different substrate temperatures by a simple and inexpensive method of air pressure chemical vapor deposition. The structural characteristics, and optical, electrical, and self-cleaning properties of the ITO thin films were investigated. It is clear that all films have a polycrystalline structure. In the sample synthesized at 550 °C, the preferred growth direction is in the direction of (222), but in the films synthesized at 450° and 500 °C, it is in the direction of (400). In the FESEM figures for all temperatures, the size of the nano-particles is less than 35 nm. In addition, all films have a relatively uniform surface. The analysis (EDX) was used to determine the chemical composition of these films. Transmission and reflection spectra of these films were examined in the 300–1000 nm spectral range and, for investigated films, the transmission coefficients in the visible regions exceed 80% and are weakly affected by deposition temperature. The optical band-gap values, Eg, ranged between 4.1 and 4.2 eV. In self-cleaning properties, the sample synthesized at 550 °C had the highest roughness and the highest contact angle and is a relatively good hydrophobic surface.