ZnO thin films with a strong c-axis orientation have been successfully deposited on Si substrate at room temperature(RT)by using JPGF-450 r. f. magnetron sputtering system. A sintered ceramic ZnO target with 99.99% purity was used as source material. A mixture of Ar(99.999%)and O

2

(99.999%) were used as sputtering gases. The argon and oxygen were introduced via two separately controlled leak valves so that the partial pressure could be adjusted. During film deposition

the argon partial pressure maintained at 1Pa

and the oxygen partial pressure maintained at 0

2 and 5.2Pa respectively for different samples. The sputtering r. f. power was 200W and sputtering time was 20 minutes. The ZnO films were grown with argon partial pressure of 1Pa and oxygen partial pressure of 0

2 and 5.2Pa

respectively. The XRD spectra revealed that all samples were polycrystalline and had a preferred orientation with c-axis perpendicular to the substrates. All samples show typical luminescence behavior with a narrow 446nm(2.78eV)emission peak when excited with 300nm light. The intensity of the PL peaks is found to be strongly dependent on the oxygen pressure during films deposition. As the oxygen partial pressure increase

the PL intensity decreases quickly. The blue emission is also affected by annealing in different ambient. For the vacuum annealed sample

the intensity of PL increases markedly. On the contrary

for the samples annealed in oxygen

the PL intensity decreases. The experiments prove that the luminescence emission peak located at 446nm corresponds to the electron transition from the shallow level of oxygen vacancy to valence band.