Hydrogenated microcrystalline silicon (muc-Si:H) films have been prepared by plasma-enhanced chemical vapour deposition (PECVD) from a mixture of silane highly diluted in hydrogen. The effect of the molecule dwell time on the deposition rate and on the electrical and structural properties has been investigated. The molecule dwell time appears to control orientation and grain size. Highly conductive muc-Si:H films with a rough surface have been grown at a high deposition rate at higher molecule dwell time in an appropriate silane concentration. These films show an enhancement of the optical absorption in the near-infrared region suitable for photovoltaic applications.