Mo doped ZnO thin films (ZnO:Mo, MZO) were prepared on quartz glass substrates by RF magnetron sputtering at the lower substrate temperatures (room temperature (RT) and 100°C). Their structural, electrical and optical properties were studied by X-ray diffractometry (XRD), four probe technique, Hall measurement, and UV-VIS-NIR spectrophotometer, respectively. XRD showed that the resultant films were wurtzite structure with c-axis preferential orientation. As the substrate temperatures increasing, the thickness of the film increased and the crystallinity became better. The resistivity of the films were 3.44x10-3 Ω•cm and 3.31x10-3 Ω•cm for the films deposited at RT and 100°C, respectively. The corresponding average transmittance in visible and near IR region (400-1100nm) was 81.7 % and 74.5 %, respectively. In addition, for the film deposited at 100°C, the refractive index (n) and band gap (Eg) were obtained by fitting the transmittance spectra and discussed.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.