Ti nanoparticles decorated ZnO nanowires heterostructure: photocurrent and photoluminescence properties

Abstract

In this work, we have investigated the effect of Ti nanoparticles (NPs) decoration on the photoluminescence (PL) and photodetection behaviour of ZnO nanowires (NWs) array. ZnO/Ti NW heterostructure was fabricated by synthesising dense NW arrays by uniform decoration of Ti NPs of two different sizes on the surface of the vertically aligned ZnO NWs. The PL spectra shows systematic enhancement (four to six folds) in the UV PL intensity, and also shows corresponding changes in the visible emission with reference to the bare ZnO NWs. We found a major improvement in the photocurrent (PC) and a much faster photoresponse from the ZnO/Ti NW heterostructure. Our studies show that when the thickness of the Ti metal layer is doubled, further improvement in the PC and photoresponse time is obtained from the ZnO/Ti NW heterostructure. The enhancement in the PL and PC are explained on the basis of interfacial charge transfer between Ti NPs and ZnO NWs.