Effects of chemical composition on the optical properties of Zn1−xCdxO thin films

Abstract

Zn 1 − x Cd x O thin films were deposited on (0001) sapphire substrates by pulsed-laser deposition. Structural and optical properties of Zn1−xCdxO films were strongly correlated to the processing conditions. The composition of the films varied nonmonotonically as a function of deposition temperatures due to the difference of vapor pressure between Cd and Zn species. The optical energy bandgap of Zn1−xCdxO thin films, measured by photoluminescence and transmittance, changed from 3.249to3.291eV. The change of the optical properties was mainly attributed to the change of the stoichiometry of Zn1−xCdxO, as determined by Rutherford backscattering spectroscopy.