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 In۲O۳ (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 ۵۵۰ °C under different argon rates (from ۵۰ to ۱۵۰ mL/min) and pressures (from ۱۰ to ۶۵۰ torr) for ۴۵ 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 ۰º before annealing. XRD patterns illustrated that all the films are polycrystalline of Cbb structure with preferentially oriented along (۲۲۲) plane. The SEM images showed that the grain size of ITO nanoparticles and the thickness of the films were obtained at about ۷۰-۱۵۰ nm and ۴۰۰-۴۵۰ 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 (۸۲ Ω/Square and resistivity and or ۳.۶۹×۱۰۴ Ω.cm) were achieved for thin films annealed under pressure of ۱۰ torr and argon rate of ۱۵۰ mL/min So that its transmission range was above ۸۱% and its band gap about ۳.۷۳ 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.

Keywords:

tin , doped indium oxide ITO Sol , gel spin coating Argon atmosphere Pressure