Highly oriented ZnO films grown by laser evaporation

Abstract

A relatively new deposition technique involving laser-assisted evaporation is applied to the deposition of thin ZnO films. Highly oriented and crystalline films of ZnO were obtained by CO2 laser evaporation of ZnO powder targets on substrates held at 50–450 °C. Optical transmission spectra of these films show a sharp cutoff at 380 nm. The refractive index, as measured by ellipsometry, is 1.98–2.04. As-grown films are conducting (0.1–1 Ω cm), but become insulating when 0.1% Li2O is added to the source. SAW devices built with these films proved the piezoelectric nature of laser-evaporated ZnO. It is found that the laser deposition technique is applicable to producing device quality ZnO films with good reproducibility.