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Abstract: ZnO films were grown on (0001) LiNbO3 substrates by metal organic chemical vapor deposition (MOCVD). Annealing of ZnO films was performed in air for 1h at 800°C. The effects of annealing on the structural and optical properties of ZnO thin films on LiNbO3 substrates were investigated using X-ray diffraction (XRD), atomic force microscopy (AFM) and photoluminescence (PL) measurements. XRD patterns and AFM showed that the as-grown and the annealed ZnO films grown on LiNbO3 substrates had c-axis preferential orientation, the crystallinity of the ZnO films grown on LiNbO3 substrates was improved, and the grain size increased by annealing. The PL spectra showed that the intensity of the UV near-band-edge peak was increased after annealing, while the intensity of visible peak (deep-level emission) decreased. [Copyright &y& Elsevier]

Abstract: ZnO thin films were grown on (0001) LiNbO3 substrates by the MOCVD technique. The substrate temperatures during growth were changed from 400 to 600°C. The X-ray diffraction (XRD) pattern of the ZnO film showed a strong [002] reflection peak, and the peak intensity was dependent on substrate temperature. The ZnO columnar grains were highly oriented along the (002) direction when the film processing temperature was 600°C. The optical transmission and PL results also indicated that highest crystalline quality of the ZnO films could be obtained at elevated temperatures. [Copyright &y& Elsevier]

Abstract: Lattice-matched (Δa/a=1.8–3.4%) (001) LiGaO2 substrates have been employed for the first time to grow ZnO thin films by pulsed-laser deposition at 350–650°C with oxygen partial pressure of 20Pa. XRD shows that a highly c-axis-oriented ZnO film can be deposited on (001) LiGaO2 substrate at 500°C. AFM images reveal the surfaces of as-deposited ZnO films are smooth and root-mean-square values are 6.662, 5.765 and 6.834nm at 350, 500 and 650°C, respectively. PL spectra indicate only near-band-edge UV emission appears in the curve of ZnO film deposited at 500°C. The deep-level emission of ZnO film deposited at 650°C probably results from Li diffusion into the film. All the results illustrate substrate temperature plays a pretty important role in obtaining ZnO film with a high quality on LiGaO2 substrate by pulsed-laser deposition. [Copyright &y& Elsevier]

Abstract: γ-LiAlO2 layers with a highly preferred (100) orientation were prepared by vapor transport equilibration (VTE) technique on (0001) sapphire substrate. Microstructure of the γ-LiAlO2 layers was studied by XRD and SEM. In the temperature range from 750 to 1100°C, the residual stress in the γ-LiAlO2 layers varied from tensile to compressive with the increase of VTE temperature, and the critical point of the change between tensile and compressive stress is around 975°C. [Copyright &y& Elsevier]

Single-phase γ-LiAlO2 layer with a preferred (1 0 0) orientation on (0 0 0 1) sapphire substrate is successfully fabricated by vapor transport equilibration (VTE) technique. The VTE-treated surface of (0 0 0 1) sapphire is polycrystalline shown to be a single-phase of γ-LiAlO2 at low VTE temperature (750–900°C), and becomes highly oriented in [1 0 0] direction at proper VTE temperature of ∼1100°C. The transparence of the obtained γ-LiAlO2//sapphire(0 0 0 1) is greatly enhanced as the γ-LiAlO2 layer becomes oriented. These results reveal the possibility of fabricating γ-LiAlO2(1 0 0)//sapphire(0 0 0 1) composite substrate by VTE for M-plane GaN-based epitaxial film. [Copyright &y& Elsevier]