Electrical and optical properties of indium-tin oxide (ITO) films by ion-assisted deposition (IAD) at room temperature

Indium-tin oxide (ITO) films have been traditionally deposited at elevated substrate temperature of 400°C to achieve low resistivity and high transmission. In some cases, films deposited at low substrate temperatures can be annealed at higher temperature to achieve lower resistivity. In this paper, thin films of ITO with various oxygen flow rates are prepared by ion-assisted electron beam evaporation at room temperature. Electrical, optical and structural properties of ITO thin films have been investigated with the function of oxygen flow rate, rate of deposition and layer thickness. Low resistivity of 7.5 × 10−4Ω-cm, high optical transmittance of 85% at wavelength 550 nm, optical band-gap of 4.2 eV and crystalline ITO films can be achieved at room temperature almost one order smaller than that prepared by other method.