We report on the use of pulsed plasma-enhanced chemical vapor deposition (P-PECVD) technique and show that "state-of-the-art" amorphous silicon (a-Si:H) materials and solar cells can be produced at a deposition rate of up to 15 Angstrom/s using a modulation frequency in the range 1-100 kHz. The approach has also been developed to deposit materials and devices onto large area, 30 cm x 40 cm, substrates with thickness uniformity (< 5%), and gas utilization rate (> 25%). We have developed a new "hot wire" chemical vapor deposition (HWCVD) method and report that our new filament material, graphite, has so far shown no appreciable degradation even after deposition of 500 mum of amorphous silicon. We report that this technique can produce "state-of-the-art" a-Si:H and that a solar cell of p/i/n configuration exhibited an initial efficiency approaching 9%. The use of microcrystalline silicon (Pc-Si) materials to produce low-cost stable solar cells is gaining considerable attention. We show that both of these techniques can produce thin film muc-Si, dependent on process conditions, with 1 1 1 and/or 2 2 0 orientations and with a grain size of approx. 500 A. Inclusion of these types of materials into a solar cell configuration will be discussed. (C) 2002 Elsevier Science B.V. All rights reserved.