Photo-production and photo-bleaching of dangling bonds by ultra-violet irradiation and annealing were observed via electron spin resonance studies of amorphous hydrogenated material. A model which involved long-range H diffusion and H evolution was proposed in order to account for the electron spin resonance spectral line-shapes which were observed after ultra-violet irradiation and annealing. A Gaussian distribution of activation energies for long-range H diffusion was used to explain the observed decrease in spin susceptibility after thermal annealing. A best fit to the spin susceptibility data indicated an average activation energy of 0.0475eV and a half-width, of the Gaussian distribution, of 0.027eV.

I.M.Brown, S.H.Lin, B.J.Feldman: Physical Review B, 1997, 56[3], 994-6