Improving the morphology and electro-optic properties of ITO thin film, by changing argon rate and atmosphere pressure

In this research study, we report the characteristics of Sn-doped In2O3 (ITO) films intended for use as transparent conducting electrodes. The ITO thin films were deposited using spin coating method in the frame of a sol-gel process in the presence of polyvinyl alcohol (PVA) as a binder. After using the sol-gel spin coating method, Indium tin oxide thin films were annealed at 550 °C under different argon rates (from 50 to 150 mL/min) and pressures (from 10 to 650 torr) for 45 min. The influence of different rates of argon pressure on the microstructure, and electrical and optical properties of ITO surfaces were evaluated using XRD, EDX, SEM, UV–Vis, and four-point probe. Wettability of the ITO surface was indicated in hydrophobicity with a contact angle (CA) of 0º before annealing. XRD patterns illustrated that all the films are polycrystalline of Cbb structure with preferentially oriented along (222) plane. The SEM images showed that the grain size of ITO nanoparticles and the thickness of the films were obtained at about 70-150 nm and 400-450 nm, respectively. The analyses were mainly proven here to highlight the role of the rate of argon atmosphere and pressure on the microstructure and the optical and electrical properties of the films. Increasing argon atmosphere and decreasing pressure increase the conductivity and crystallization of samples. The obtained results indicated that minimum sheet resistance (82 Ω/Square and resistivity and or 3.69×104 Ω.cm) were achieved for thin films annealed under pressure of 10 torr and argon rate of 150 mL/min So that its transmission range was above 81% and its band gap about 3.73 eV. This sample has better results than the other samples in different conditions and has the best results compared to similar cheap methods. The process was tested repeatedly in data measurement and manufacturing to ensure its repeatability.