Persistent photoconductivity ina−Si:H/a−SiNx:Hlayered structures

A persistent photoconductivity effect, which lasts for many minutes at room temperature after a brief exposure to light, is observed in multiple thin layers of alternating $a-\mathrm{Si}:\mathrm{H}$ and $a-\mathrm{Si}{\mathrm{N}}_x:\mathrm{H}$. In addition, the samples in the dark are found to get polarized upon application of low electric fields, parallel to the layers. The depolarization takes several minutes at 300 K. The results are explained in terms of deep traps at the interfaces.