Gap-state distribution in evaporateda-Si without and with posthydrogenation using space-charge-limited-current method

The gap-state distribution of evaporated a-Si is studied by space-charge-limited-current method in the sandwich structure. A predominant peak in the gap-state distribution positioned at $E_c$-0.52 eV is found in annealed evaporated a-Si. This peak is supposed to arise from dangling bonds. After posthydrogenation, the gap-state density is found to be flat from below midgap up to $E_c$-0.3 eV, after which the gap-state density begins to rise exponentially towards $E_c$. Posthydrogenation has removed the gap states at $E_c$-0.52 eV.