Plasmon-induced photoexcitation of “hot” electrons and “hot” holes in amorphous silicon photosensitive devices containing silver nanoparticles

Abstract

We report on a plasmon-induced photocurrent in photosensitive devices based on hydrogenated amorphous silicon (a-Si:H) containing silver nanoparticles (NPs). The photocurrent is measured in a spectral region corresponding to optical transitions below the band gap of a-Si:H. Photoexcitation of “hot” electrons in the NPs or in defect states present in the vicinity of the NPs, resulting from plasmon decay in the NPs, is often cited as being responsible for this effect. In this study, we demonstrate that plasmon induced photogeneration of “hot” holes is also able to contribute to a photocurrent. A bifacial symmetrical transparent device was prepared in order to compare the internal quantum efficiency of both processes, the first based on the photogeneration of “hot” electrons and the second based on the photogeneration of “hot” holes.