Conduction-Band Density of States in Hydrogenated Amorphous Silicon Determined by Inverse Photoemission

The first direct determination of the conduction band of hydrogenated amorphous silicon has been performed by means of x-ray inverse photoemission. We found a feature 1.2-4 eV above the Fermi level which may be associated, on the basis of its annealing behavior and energy position, with the Si-H antibonding orbital. Comparison with data on crystalline silicon clearly shows that the amorphous-silicon conduction-band density of states does not exhibit critical-point structures.