An experimental observation of photo-induced carrier multiplication in hydrogenated amorphous silicon

A photo-induced carrier multiplication in a hydrogenated amorphous silicon has been observed. A careful measurement of photo-carrier generation has been done with amorphous silicon Schottky barrier structure junctions as a function of incident photon energy in the range between 1.55eV and 6.2eV. The quantum efficiency is estimated to be multiplied by a factor of two in higher photon energy region than 5.4eV. This multiplication can be explained by an interband carrier ionization due to the energy given by a high energy photo-carrier.