Gallium-Modified Zinc Oxide Thin Films Prepared by Chemical Solution Deposition

Gallium-doped ZnO (GZO) thin films on glass, which can be used as transparent electrodes, were prepared using a spin coating technique. Thermal analysis and Fourier-transform infrared spectroscopy of the dried precursor solution of Zn acetate and Ga nitrate dissolved in ethanol with diethanolamine confirmed the decomposition of the organic components upon heating and the formation of ZnO at 450 & DEG;C. The thin films fired at 600 & DEG;C in oxygen and air, and the films annealed at 400 & DEG;C in Ar/H-2,H- were polycrystalline, 140 nm thick, and exhibited a homogeneous microstructure with 50 nm grains and a smooth surface, as shown by X-ray powder diffraction and scanning electron and atomic force microscopy. The sheet resistance R-s measured using the 4-probe technique showed a change in R-s within 80 days for all samples. The R-s of the GZO thin films annealed in oxygen and air with values of M & omega;/sq decreased over time. R-s values of 150 k & omega;/sq were obtained for GZO thin films annealed in Ar/H-2, but the R-s increased over time. We suggest that the degradation of R-s is related to the adsorption of water on GZO and that the responses depend on the nature of the defects in the GZO lattice.

Automated summary

Gallium-doped ZnO (GZO) thin films were prepared by spin coating technique and used as transparent electrodes. Thermal analysis confirmed the decomposition of organic components and formation of ZnO at 450°C. The thin films were polycrystalline with a smooth surface, and the sheet resistance varied over time depending on annealing conditions.