Single-crystalline sodium-doped p-type ZnO and ZnMgO nanowires via combination of thin-film and nano techniques

The p-type doping of ZnO is the key to ZnO-based light-emitting devices and has proven to be difficult. ZnO nanowires (NWs) are an ideal platform for the study of p-type doping due to their high crystal quality and easy growth. In this Article, we demonstrate an innovative approach via the combination of thin-film and nano techniques to fabricate single-crystal p-type ZnO and ZnMgO NWs. Using undoped ZnO NWs as templates, Na-doped ZnO and ZnMgO layers are deposited by pulsed laser deposition, forming core-shell NWs. Single NW field effect transistors are fabricated to testify the p-type conductivity. It is found that postannealing is crucial to activate the Na acceptor. The present method offers better controllability and reproducibility for fabricating p-type ZnO layers, which are advantageous for optoelectronic applications. © 2011 American Chemical Society.