Growth and characterization of high quality homoepitaxial ZnO films by RF magnetron sputtering

Zinc oxide (ZnO) films were grown on bulk ZnO substrates by the RF magnetron sputtering system. High resolution x-ray diffraction and photoluminescence spectra of the homoepitaxial films showed sharp and intense peaks with full-width at half-maximum values of 10–65 arcsec ((0 0 0 2) peak) and 106–116 meV (band edge emission), respectively, representing crystalline qualities better than or comparable with ZnO films grown by molecular beam epitaxy. It was also observed that ZnO films grown on Zn-face substrates showed a higher quality than those on O-face wafers. Doping of the films with about 1 wt% Ga resulted in n-type materials with about 1.5 × 1018 cm3 free electron density.