Large enhancement of photocurrent gain based on the composite of a single n-type SnO2 nanowire and p-type NiO nanoparticles

The high sensitivity of photodetector in the UV range based on the composite consisting of a single SnO2 nanowire and NiO nanoparticles has been demonstrated. The underlying mechanism is attributed to the formation of p-NiO and n-SnO2 heterojunction on the nanowire surface. The enhanced space charge region owing to the existence of p-n heterojunction increases the surface electric field, which will improve the separation of photogenerated electrons and holes, and the photoresponse gain will be greatly enhanced. This work shows a new approach that by decorating suitable p-type nanoparticles on n-type nanowires, the photoresponse gain can be enhanced drastically. Our result should be useful for creating novel high efficiency photodetectors. (C) 2011 Optical Society of America