Polycrystalline ZnO thin films have been grown on Si (100) substrate using filtered cathodic vacuum are technique. Room temperature photoluminescence reveals a strong near-band edge emission at 378 nm and a weak green emission at around 510nm from the ZnO film deposited at 230 degreesC. The intensity ratio ol the near-band edge emission to green emission is about 100 indicating the high quality of the film. An additional emission at 420 nm, corresponding to the interstitial oxygen level, is also observed from the film grown at 430 degreesC. The ZnO thin films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, as well as transmittance measurement.