Electrical and optical properties of electron beam evaporated ITO thin films

Indium tin oxide (ITO) thin films were prepared on glass substrates by an electron beam evaporation technique from a mixture of In2O3 and SnO2. The films were annealed in air for 30 min at 350°C. The electrical and optical properties of these films were investigated as a function of the substrate temperature. The films were deposited at substrate temperatures ranging from 50 to 350°C at an oxygen partial pressure of 5×10−5 mbar. The dopant concentration, resistivity, electrical conductivity, activation energy, optical transmission and band gap energy were investigated. It was found that the activation energy decreased with an increase in the film thickness. A transmittance value of 92% in the visible region of the spectrum and a resistivity of 3×10−6 Ωm was obtained at a substrate temperature of 350°C. Structural studies showed that the films were polycrystalline.