NONEQUILIBRIUM CARRIERS IN A-SI-H STUDIED BY ELECTRON-SPIN-RESONANCE AND IR-EXCITATION

The changes in the lineshape of the ESR-spectra of undoped and doped a-Si:H are recorded under steady state illumination with bandgap light (LESR) and in the metastable state after excitation (residual LESR) as a function of temperature, intensity of the exciting light and IR excitation (h nu less than 0. 7 ev). The results are related to measurements of photoluminescence (PL) and photoconductivity (PC). It is suggested that under illumination at low temperature the time limiting process for recombination is the tunnel transition of a band tail hole to neutral and negatively charged dangling bonds. In p-type films the IR-induced effects of LESR, PL and PC are attributed to the excitation of holes from the valence band tail and of electrons from negatively charged dangling bonds.