EFFECT OF THE CHARGE-STATE OF DEFECTS ON THE LIGHT-INDUCED KINETICS OF THE PHOTOCONDUCTIVITY OF AMORPHOUS HYDRATED SILICON

The photoconductivity and defect density in films of nondoped a-Si:H s oaked with light (W = 114 mW/cm(2), lambda<0.9 mu m) for 5 h were inve stigated. It is shown that sigma(ph)similar to t(-gamma) and N-D simil ar to t(beta), where gamma>beta or gamma similar or equal to beta, dep ending on the position of the Fermi level prior to light soaking, i.e. , depending on the charge state of the defects: D- and D-0 or D+ and D -0. It is also shown that the light-induced kinetics of sigma(ph) is a ffected by a transition of the defects into the D-0 state because of a corresponding shift of the Fermi level during light soaking. (C) 1998 American Institute of Physics.