Hydrogenation and the density of defect states in amorphous silicon

We discuss the nature and density of defects in pure amorphous silicon, under the light of recent hydrogenation experiments. It is argued that a reliable measure of defect densities can be obtained by counting the number of hydrogen atoms that can be incorporated in a pure starting material by subsequent plasma treatment. This leads to interpretation of hopping conductivities in terms of a Fermi level density of states Nf in excess of 1020 cm-3 eV-1 and wave function spatial extent of the order of 2.5 Å. This figure is shown to be reasonable for a dangling bond wavefunction. © 1979.