The effects of annealing temperature on the structural and optical properties of ZnO films grown on Si (100) substrates by sol-gel spin-coating were investigated. The structural and optical properties were characterized by X-ray diffraction, scanning electron microscopy and photoluminescence spectra. X-ray diffraction analysis showed the crystal quality of ZnO films became better after annealing at high temperature. The grain size increases with the temperature increasing. It was found that the tensile stress in the plane of ZnO films first increases and then decreases with the annealing temperature increasing, reaching the maximum value of 1.8 GPa at 700C. PL spectra of ZnO films annealed at various temperatures consisted of a near band edge emission around 380nm and visible emissions due to the electronic defects, which were related to deep level emissions, such as oxide antisite (OZn), interstitial oxygen (Oi), interstitial zinc (Zni) and zinc vacancy (V−Zn), which were generated during annealing process. The evolution of defects was analyzed by photoluminescence spectra based upon the energy of the electronic transitions.

Effects of Annealing Temperature on Structural and Optical Properties of ZnO Thin Films. J.P.Xu, S.B.Shi, L.Li, X.S.Zhang, Y.X.Wang, X.M.Chen: Chinese Physics Letters, 2010, 27[4], 047803