Ultrahigh-gain single SnO2 nanowire photodetectors made with ferromagnetic nickel electrodes

Abstract

We report the first attempt at magnetic manipulation of the photoresponse in a one-dimensional device in which a highly sensitive ultraviolet photodetector, composed of tin dioxide nanowire (SnO2 NW) and ferromagnetic nickel (Ni) electrodes, has been fabricated and characterized. Surprisingly, as the Ni electrodes were magnetized, the photocurrent gain was greatly enhanced by up to 20 times, which is far beyond all of the previously reported enhancement factors for functionalized NW photodetectors. The underlying mechanism enabling the enhanced gain is attributed to both oxygen molecules adsorbed and surface band-bending effects due to the migration of electrons to the surface of SnO2 NW caused by the magnetic field of ferromagnetic electrodes. The novel approach presented here can provide a new route for the creation of highly efficient optoelectronic devices based on the coupling between ferromagnetic materials and nanostructured semiconductors. © 2012 Nature Japan K.K. All rights reserved.