The slow relaxation of the persistent photoconductivity (PPC) effect in sulfur-doped hydrogenated amorphous silicon (a-Si:H) has been measured as a function of temperature and illumination time. The relaxation is found to be thermally activated, with an activation energy which varies with sulfur concentration, while illuminating the film for a longer time leads to a longer relaxation time. A correlation is observed between changes of the photoconductivity during illumination and the magnitude of the PPC effect following illumination. These effects are also observed in compensated a-Si:H, suggesting that the mechanism for the PPC effect is the same in both sulfur-doped a-Si:H and compensated a-Si:H. The presence of donor and compensating acceptor states in sulfur-doped a-Si:H could arise from valence alternation pair sulfur atom defects.
|Original language||English (US)|
|Number of pages||6|
|Journal||Materials Research Society Symposium - Proceedings|
|State||Published - 1996|
|Event||Proceedings of the 1996 MRS Spring Symposium - San Francisco, CA, USA|
Duration: Apr 8 1996 → Apr 12 1996