Zinc oxide with high stability and a direct band gap of 3.37eV has attracted tremendous attention in recent years because of its high potential for application as short wavelength optical devices. Several techniques such as pulsed laser deposition

reactive thermal evaporation

sol-gel have been employed to synthesize high quality ZnO thin films. Sol-gel method was adopted to make ZnO thin films on n-Si (100) and they could be investigated from three parts. The X-ray diffraction spectra indicates that the structure of the ZnO thin films is polycrystal wurtzite structure with

c

axis preferred orientation. The annealing time and the annealing tempe-rature has great effect on the structure and particle size of the films

the proximate annealing temperature is around 500℃ by comprehensive experiments. The surface and profile character of the ZnO thin films can be observed by the Scanning Electrical Microscopy

which indicates that the growth of the films is uniform

the polycrystalline dimensions were determined to be in the range of 70~160 nm

consistent with the X-ray diffraction results. The optical properties of ZnO nanowires were investigated by room-temperature photoluminescence spectroscopy using a Xe lamp with an excitation wavelength of 230 nm. The photoluminescence of the ZnO sol indicates that as the aging time went on

the ultraviolet peak position moved to the short wavelength

from 342 to 340

339 nm. The photoluminescence spectrum of the ZnO thin films at room temperature indicates that the ultraviolet peak positions were at 365

390 nm

and the intensities of the emission were stronger

while the visible emission at 435 nm didn’t change obviously. The stronger peak positions at 460 and 690 nm are twice and three times frequency multiplication of the excitation light. The visible emission showed a weaker deep-level green emission than UV emission without being completely restrained. The PLspectra showed a strong peak around 390 nm at room temperature

corresponding to the ZnO free exciton emission.