We have used the room-temperature constant-photocurrent method and dark-conductivity measurements to study the annealing kinetics of light-induced metastable defects in a set of a-Si1-xCx:H (x less than or equal to 0.11) films. Light-induced metastable defects created at room temperature started annealing at higher temperatures for alloys with high carbon contents. The annealing activation-energy distribution function was calculated to be a narrow Gaussian peaked at about 1 eV for the unalloyed sample. For the alloys, the peak position shifts to higher energies with increasing carbon content. The variation of the dark conductivity of the samples was measured as a function of annealing time and annealing temperature. A similarity between the observed increase in the dark conductivity and the annealing rate of light-induced defects was identified. (C) 2003 Kluwer Academic Publishers.