ZnO Nanowire Heterostructures: Intriguing Photophysics and Emerging Applications

Over the last decades, semiconductor nanowires have been extensively studied for their applications in several disciplines. Many of these applications require heterostructures, which can be defined as the combination of two or more materials within the same nanowire structure. Recent research on the ZnO nanowires (NWs) heterostructures shows the possibility to overcome the existing limitation of the bare ZnO NWs based optoelectronic devices. Prospects for the commercialization of ZnO NWs based devices using the heterostructure approach are intensively pursued at present. This review article summarizes the current status of research worldwide and the findings from our group on various aspects of the ZnO NW heterostructures: fabrication methodologies, structural characterization, photophysical properties and related emerging applications. The fascinating properties of the ZnO NW heterostructures and its applications in different devices, mainly UV photodetectors, light-emitting-diodes, dye sensitized or quantum dots sensitized solar cells and photoelectrochemical cells are discussed. Focus of the article is on the impact of heterostructure approach on the selective properties and performance of the ZnO NWs based devices. The improvements in the key parameters of these devices are also discussed to highlight the effectiveness of the heterostructure approach and a future outlook of the field is presented at the end.