An  in situ  photo-electron spectroscopic investigation was made of the changes in composition and electronic density of states, on the surface of amorphous hydrogenated material, which occurred upon exposure to atomic H at temperatures of between 100 and 400C. The effect of this so-called chemical annealing was a reduction in the H that was bonded to the surface and in the near-surface density of gap states. Both effects were enhanced at higher temperatures. The maximum reduction in the defect density, due to the chemical annealing (that is, due to the action of atomic H alone), amounted to 40%. An important feature of chemical annealing during the layer-by-layer deposition of amorphous hydrogenated material was an enhanced susceptibility of the sample surface to O contamination during the chemical annealing step. This appeared to be inherent to the process.

J.Ristein, C.Appelt, T.Gertkemper, L.Ley: Solid State Phenomena, 1995, 44-46, 775-90