Results of photoresponse, activation energy and light soaking measurements on selected hydrogenated nanocrystalline Si thin films are presented. The films were deposited by hot-wire chemical vapour deposition. Values of photoresponse better than I X 102 were obtained. They are lower for porous material as the crystalline volume fraction increases. Activation energy results are related to the intrinsic character and the microstructure of the films. Light soaking experiments show that the nanocrystalline films are very stable. Their amorphous counterparts attain a stable photoconductivity value after 300 h of illumination. (c) 2007 Elsevier B.V. All rights reserved.