Facile assembly of n-SnO 2 nanobelts–p-NiO heterojunctions with enhanced ultraviolet photoresponse

We present a highly transparent heterojunction photodiode by precisely aligning n-type SnO2 nanobelts on top of a p-type NiO thin film. This p-n junction diode demonstrates stable rectifying characteristics as well as greatly enhanced ultraviolet photoresponse, which exhibits an ultrahigh photosensitivity of up to 10(5) with accelerated response speed under reverse bias.