Dependence of the saturated light-induced defect density on macroscopic properties of hydrogenated amorphous silicon

We report a study of the saturated light-induced defect density N _s,sat in 37 hydrogenated (and in part fluorinated) amorphous silicon [a-Si:H(F)] films grown in six different reactors under widely different conditions. N_s,sat was attained by exposing the films to light from a krypton ion laser (λ=647.1 nm). N_s,sat is determined by the constant photocurrent method and lies between 5×10¹⁶ and 2×10¹⁷ cm^-3. N_s,sat drops with decreasing optical gap E_opt and hydrogen content c_H, but is not correlated with the initial defect density N_s,ann or with the Urbach tail energy E_u. We discuss our results within the framework of existing models for light-induced defects.