The influence of spin defects on recombination and electronic transport in amorphous silicon

Photoluminescence, photoconductivity, and dark hopping conductivity of a-Si : H have been measured as a function of defect concentration. The network defects were created by electron bombardment and by hydrogen effusion. Both methods were successively applied to samples prepared in the same run. The defect concentration was monitored by spin resonance measurements. Our results can be explained with the assumption of essentially two kinds of defect : dangling-bond and vacancy-type defects. It is necessary to assume a positive effective correlation energy for both kinds of defect.