The effect of growth temperature on physical properties of heavily doped ZnO:Al films

Abstract

Heavily-doped ZnO Al film have been deposited on high temperature stable glass substrates using radio-frequency (RF) magnetron sputtering. The effect of growth temperature on physical properties of the films has been investigated. The microstructure evolved a columnar structure into a granular one with the increase in growth temperature and then a typical honeycomb type microstructure representing huge grain formation indicating high densification. All Al-doped ZnO films exhibited high optical transparency and the absorption edge shifted to the short wavelength (blue-shift) as the growth temperature increased. The dense microstructure with a high crystallographic quality and large grains evolved at 500 degrees C enabled us to obtain 2.28 x 10(-3) Omega cm and high visible transmittance over 90% even if the ZnO film was doped with an Al content of approximately 5.5 at%. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim