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