Investigation of negative photoconductivity in p-type Pb_(1-x)Sn_xTe film

摘要

We investigated the negative photoconductivity (NPC) effect that was observed in a p-type Pb_(1-x)Sn_x Te film for temperatures varying from 300 K down to 85 K. We found that this effect is a consequence of defect states located in the bandgap which act as trapping levels, changing the relation between generation and recombination rates. Theoretical calculations predict contributions to the NPC from both conduction and valence bands, which are in accordance with the experimental observations.