Thickness-dependent conductivity and photoconductivity of hydrogenated amorphous silicon

We summarize our recent results on thickness and surface variations in the conductivity and photoconductivity of phosphorus-doped n-type hydrogenated amorphous silicon films. Our principal finding is that thinner films have lower conductivities, higher activation energies and, for a certain range of thicknesses, higher photoconductivities. A speculation is given for the origin of the enhanced photoconductivity in terms of field-assisted carrier separation in the surface barrier region. © 1980.