ZnO films with <110> orientation were grown on R-Al 2O 3 substrates by LP-MOCVD, and the growth temperature was optimized. The quality of crystal, surface morphology and optical characteristic of the samples were investigated by XRD, AFM and PL method. The experimental results show that the FWHM of the optimized sample is only 0.50°. Compared with that of the sample grown on C-Al 2O 3 material under the same conditions, the surface morphology of the first sample is denser and smooth, while the PL spectra indicate that the exciton emitting intensity of <110> oriented ZnO film in the ultraviolet range is lower. However, the deep-level emission related to the intrinsic defects disappears in the spectrum. All above indicate that the <110> oriented ZnO film is more suitable for fabrication of the film SAWF with a low loss and a high frequency than for fabrication of the emitting device in ultraviolet range.
The structural and the optical properties of ZnO films with high quality grown via plasma-enhanced metal\|organic chemical vapour deposition(MOCVD) on C-plane sapphire substrate were studied. The crystallinity and the optical properties of the films are greatly improved having been annealed in oxygen plasma atmosphere. The structure, the band gap and the binding energy of O 1s electrons, and the molar ratio of O to Zn were determined by X-ray diffraction(XRD), photoluminescence(PL) and X-ray photoelectron scan methods. For both the annealed and the as-grown films, the exciton peak features were observed at room temperature. The band-edge photoluminescence of the annealed film is much stronger than that of the as-grown film, and the exciton peak relating to the deep level at 439 nm disappears. The molar ratio of O to Zn in the annealed film is 0 91, while it is 0 78 for the as-grown film.
