Growth of ZnO Film by Plasma-assisted MOCVD

The growth of ZnO film by plasma-assisted MOCVD was reported in this atricle. From X-ray diffraction spectrum, the intensity of (0002) peak at 20=34. 56° was high, indicating a c-axis orientation perpendicular to the substrate surface in ZnO. Ultraviolet(UV) emission with a high intensity at 375 nm was attributed to the excitation emission from photoluminescence (PL) spectrum. In PL spectrum, we also found green emission with a low intensity and wide FWHM. This green emission came from deep level transition due to defect levels in ZnO film. The ratio of the intensity of UV emission to that of green emission was as high as 193, indicating a high quality of the samples. This high quality was also confirmed by Atomic Force Microscope (AFM) analysis. Two methods were used in order to get ZnO film with a high resistivity. One was annealing ZnO film every ten minutes under relative high pressure of oxygen (O₂) at 700°C, the other was N-doping by N₂. ZnO film with a high resistivity was successfully prepared. The resistivity was 5×10⁴ Ω • cm and 1 100 Ω • cm, respectively, while that of untreated sample was as low as 0. 65 Ω • cm. Furthermore, N-doped sample had a higher resistivity and better photoluminescence properties than that of the sample obtained by annealing under oxygen.