Structural and optical properties of ZnO films produced by a nonvacuum chemical technique

Zinc-oxide films are grown by a new nonvacuum chemical method: the pyrolysis of zinc acetylacetonate at a temperature of 280–300°C. The structural, phonon, and emission properties of the ZnO films are studied by X-ray diffraction analysis, scanning electron microscopy, Raman measurements, and photoluminescence spectroscopy. The high-intensity (0002) peak recorded in the X-ray diffraction spectra indicate the predominant orientation of crystallites in the (0001) direction in the ZnO films. From analysis of the $E_2^{\mathrm{high}}$ mode in the Raman spectrum of the ZnO films, the elastic strains $\varepsilon_{zz}$ ($\sim$ 3.2 $\times$ 10$^{-3}$) and the quality of the crystal structure are determined. The characteristics of the pyrolytic ZnO films are compared with the corresponding characteristics of ZnO films grown by molecular-beam epitaxy. As a result, the possibility of growing polycrystalline ZnO films of rather high quality by a practically feasible low-temperature technique is demonstrated.