p-Type ZnO nanowires: From synthesis to nanoenergy

Developing routes for the fabrication of semiconducting nanomaterials with complementary conduction types should extend their potential use in a wide variety of industrial applications as well as expand research frontiers. Among the most promising nanomaterials, ZnO possesses several intriguing features that have attracted great interest for its use in nano-energy-related fields. Compared with unintentionally doped ZnO nanowires (NWs), which naturally possess stable electron-dominated conduction characteristics, it is difficult to incorporate acceptors into ZnO NWs and to ensure the stable conduction properties of p-type ZnO NWs. Herein, we review recent progress related to the synthesis and potential nano-energy applications of p-type ZnO NWs, highlighting their increasing role in semiconducting nanomaterials. Nevertheless, new strategies will have to be developed to overcome currently encountered problems in the synthesis of p-type ZnO NWs and, thereby, ensure the success of future ZnO-based industries. (C) 2011 Elsevier Ltd. All rights reserved.