ZnO films deposited by optimized PLD technique with bias voltages

Abstract

AbstractThe pulsed laser deposition (PLD) technique with bias voltage application for formation of high quality ZnO films was investigated. Oxygen ambient in the PLD chamber significantly decreased the photoluminescence (PL) intensity of near band edge (NBE) emission. Then, instead of using oxygen ambient, the PLD technique with bias voltage application was optimized to attain the stoichiometric composition of the ZnO films. As the deposition temperature was increased, the X‐ray spectrum width diffracted from the (0002) planes was decreased and it showed a minimum value at 700 °C. The PL intensity of the NBE emission also had its maximum value for the film deposited at 700 °C. For the ZnO films deposited at 700 °C, the X‐ray spectrum width showed the minimum value under a bias voltage of –50 V. The PL intensity of the NBE emission also had a maximum value under the same bias voltage. Thus, ZnO films deposited under a bias voltage of –50 V at 700 °C had strong NBE emission intensities. These results could be explained not only by attaining the stoichiometric composition of the ZnO film but also by decreasing the number of high energy O2– ions which caused non‐radiative recombination centers in the film. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)