AN INVESTIGATION OF DENSITY OF GAP STATES IN AMORPHOUS SEMICONDUCTORS BY THERMOSTI-MULATED CONDUCTIVITY SPECTRA

Determination of the density of states in the uper half of gap in a-Si:H film and a-Si:H/a-SiN x : H superlattices were obtained by a more comprehensive theoretical analysis of the thermostimulated comductivity. The results are consistent with that of Fritzsche's analysis. The main features of the two different analytical approaches and the correlation between maximnm chermostimulated current emission energy E m and quasi-Fermi level were discussed. The results show that the thermostimulated conductivity in a-Si: H should be analysed in weak recombination condition. In consequence, retrapping of the thermostimulated carriers can not be negleted. Theory of Gu et al. improves the analysis of measurement of thermostimulated conductivity.