Patterned synthesis of laterally oriented ultrafine ZnO nanowires by controlled metalorganic chemical vapour deposition

Abstract

Selective and lateral growth of ultrafine ZnO nanowires using metalorganic chemical vapour deposition (MOCVD) is studied. For selective growth of ZnO nanowires, oxidized substrates were patterned with Au layers, which serve as nucleation sites for the initial stage of ZnO nanowire growth. Electron microscopy confirmed that ultrafine ZnO nanowires with a mean diameter in the range similar to 8-20 nm were rooted selectively in Au patterns and laterally extended to several micrometres on the substrate surfaces. Interestingly, nanowire bridges crosslinking the Au patterns or nanowire link-ups were frequently observed, indicating that self-organizing electrical interconnects and optical networks can be developed. Photoresponse measurements showed that exposure of the ultrafine ZnO nanowires to ultraviolet light rapidly increased the channel current from similar to 150 to similar to 400 nA at an applied bias voltage of 1V.