Light-induced creation of metastable defects in hydrogenated amorphous silicon studied by computer simulations of constant photocurrent measurements

摘要

The light-induced degradation of an intrinsic hydrogenated amorphous silicon sample has been studied from the evolution of the sub-band-gap absorption coefficient. The experimental results have been modeled using detailed numerical analysis, obtaining the defect distribution within the gap for each illumination time. These results have been compared with those previously obtained from a direct deconvolution of the absorption coefficient spectra [J. A. Schmidt, R. Arce, R. H. Buitrago, and R. R. Koropecki, Phys. Rev. B 55, 9621 (1997)]. We have found, in agreement with our previous work, that (i) the defect density shows the presence of more charged than neutral defects, as predicted by the defect pool model, and (ii) the concentration of charged and neutral defects evolve with the same time dependence, thus contradicting Schumm's generalized model of defect equilibration. [S0163-1829(99)08907-9]. [References: 25]