Effect of oxygen partial pressure on the optical properties of DC magnetron sputtered TiO2 films.

Abstract

Highly conductive and transparent aluminum-doped zinc oxide thin films were prepared by ablating the target containing 2 wt% Al2O3 with ArF excimer laser (lamda=193 nm). The films were grown at a repetition rate of 10 Hz, energy density of 2-3 J/cm2 and irradiation time of 10-60 min (6000-36000 laser shots). The optical and electrical properties of the films depend on the substrate temperature and oxygen pressure during film deposition. The lowest resistivity was found to be at 1.44 Wcm for films deposited at 300oC and in 1mtorr of oxygen ambient. The average transmittance was found to be in the range of 84-92%. Sharp decrease in transmittance and sharp increase in reflectance near the plasma edge in the near-infrared range are due to impurity scattering, which is caused by aluminum doping.