Effect of a TiO2 Buffer Layer on the Properties of ITO Films Prepared by RF Magnetron Sputtering

Sn-doped In2O3 (ITO) thin films were prepared by radio frequency magnetron sputtering without intentional substrate heating on bare glass and TiO2-deposited glass substrates to investigate the effect of a TiO2 buffer layer on the electrical and optical properties of ITO films. The thicknesses of TiO2 and ITO films were kept constant at 5 and 100 nm, respectively. As-deposited ITO single layer films show an optical transmittance of 75.9%, while ITO/TiO2 bilayered films show a lower transmittance of 76.1%. However, as-deposited ITO/TiO2 films show a lower resistivity (9.87x10(-4) Ocm) than that of ITO single layer films. In addition, the work function of the ITO film is affected by the TiO2 buffer layer, with the ITO/TiO2 films having a higher work-function (5.0 eV) than that of the ITO single layer films. The experimental results indicate that a 5-nm-thick TiO2 buffer layer on the ITO/TiO2 films results in better performance than conventional ITO single layer films.