A Unified Description of the Density of States for Hydrogen and Electrons in Amorphous Silicon

ABSTRACTWe derive the hydrogen density of states for hydrogenated Amorphous silicon (a-Si:H), which is completely consistent with the electronic density of states for the defect pool model. If silicon dangling bond energies are distributed in energy, as in a defect pool model, then the hydrogen density of states becomes quite complex, with the hydrogen binding energy dependent on the Fermi level and dangling bond transition energy. We demonstrate that the electronic density of states for dangling bonds is almost identical to our previous defect pool model, while the hydrogen density of states can account for the results of hydrogenation-dehydrogenation experiments. The effective hydrogen correlation energy is variable, being negative for most hydrogen binding sites, but positive for most defect sites.