Characteristics of a-plane ZnO Films Grown on r-plane Sapphire Substrates by Using Pulsed Laser Deposition

摘要

We investigated optimized growth parameters and annealing conditions for high-quality a-planeZnO grown with a pulsed laser deposition (PLD) technique. Through measuring the FWHM ofthe a-plane ZnO peak in the rocking curve, the optimized conditions for growing a-plane single-crystalline ZnO were an oxygen pressure of 3 x 10-4 Torr and a growth temperature of 500 °C. Afterthe deposition process, a thermal annealing process was investigated. The surface morphology, theluminescence of the UV emission, the structural anisotropy, and the carrier mobility were improvedafter thermal annealing, but annealing at temperature over 700 °C deteriorated the quality of the a-plane ZnO films. This report presents fundamentals for the growth mode and the effects of thermalannealing on non-polar ZnO.