Nanometer silicon thin films have been developed by high-frequency (HF) sputtering at low temperature. Dark and photo I-V characteristics of the films are measured at room temperature, and the result shows that the films have the Coulomb blockade effect. The average size of the nano-crystallines which are embedded in the amorphous matrix is about 10 nm. Optical gap of such films is >2.0 eV. All the films are prepared at temperature lower than 150 degreesC. (C) 2004 Published by Elsevier B.V.