In this paper, we have presented results on silicon thin films deposited by hot-wire CVD at low substrate temperatures (200 degreesC). Films ranging from amorphous to nanocrystalline were obtained by varying the filament temperature from 1500 to 1800 degreesC. A crystalline fraction of 50% was obtained for the sample deposited at 1700 degreesC. The results obtained seemed to indicate that atomic hydrogen plays a leading role in the obtaining of nanocrystalline silicon. The optoelectronic properties of the amorphous material obtained in these conditions are slightly poorer than the ones observed in device-grade films grown by plasma-enhanced CVD due to a higher hydrogen incorporation (13%).