Preparation and optimization of ZnO films on single-crystal diamond substrate by metal-organic chemical vapour deposition

High-quality ZnO thin films have been grown on single-crystal diamond substrates with (111) orientation, by low-pressure metal-organic chemical vapour deposition. X-ray diffraction spectra and photoluminescence (PL) spectra clearly showed that the quality of ZnO films was improved by the two-step growth method. Strong ultraviolet emissions and weak deep-level emissions with different intensity were both observed in the room-temperature PL spectrum. The change of surface morphology was also studied by atomic force microscopy. Zn and O elements in the deposited ZnO/diamond films were investigated by x-ray photoelectron spectroscopy, in which the statistical result of the ratio for O/Zn atoms of samples was about 1. Raman scattering was performed at room temperature. The E2, A1(TO) and E1(TO) mode peaks were seen at 437.46, 383 and 414.87 cm−1, which indicated a high crystalline quality for our samples.