Effect of annealing on the properties of (100) ZnO films prepared by chemical vapor deposition utilizing zinc acetate dihydrate

(100) ZnO films were prepared by chemical vapor deposition utilizing zinc acetate dihydrate as the evaporation source. X-ray diffraction analysis of the as-deposited ZnO film shows a strong ZnO (100) diffraction peak centered at 31.85° with a full width at half-maximum (FWHM) of 0.50°. Post-growth annealing at 750 and 1000 °C reduces the FWHM of the (100) diffraction peak to 0.26° and 0.16°, respectively. Photoluminescence of the as-deposited films shows a strong near-band-edge (NBE) emission centered at 3.14 eV which is due to defect states at the grain boundary. Post-growth annealing causes increase of defect emission and blue-shift of NBE emission. The blue-shift of NBE emission after annealing is due to re-crystallization that reduces grain boundary defects. The shift of defect emission from 1.80 to 2.25 eV indicates that the dominate defect changes from excess oxygen or zinc interstitial to defects on the surface, which is due to decomposition of ZnO.