We have grown films of a-Si:H by remote plasma enhanced chemical vapor deposition (RPECVD) with substrate temperatures Ts between 38 and 400 °C and studied the infrared and optical absorbance (including sub-band-gap absorbance), and other photoelectronic properties. The RPECVD films differ from glow discharge (GD) and sputtered films, most notably in the Ts dependence of the hydrogen bonding environments (SiH, SiH2, etc.) and the photoconductivity. RPECVD films produced with Ts=235 °C are similar to ‘‘device grade’’ GD films. Based on the differences between these films, we construct a model for the RPECVD deposition process that includes SiH3 species as precursors to the growth of high-quality films. We also present experimental evidence of the selectability of precursor formation in the RPECVD process.