A template-free electrochemical deposition route to ZnO nanoneedle arrays and theiroptical and field emission properties

Abstract

We report a soft and template-free electrochemical deposition method for preparing wafer-scaleZnO nanoneedle arrays on an oriented gold film coated silicon substrate. It has been shownthat the ZnO nanoneedles possess single-crystal wurtzite structure and grow along thec-axis perpendicularly on the substrate. Raman and resonant Raman scattering studies haveconfirmed that the ZnO nanoneedles are of good crystal quality. The room temperaturephotoluminescence spectrum of such ZnO nanoneedle arrays exhibits a strong ultravioletemission but negligible visible emission. The time-resolved photoluminescencespectral analysis discloses the excitonic origin of the ultraviolet emission. Thefield electron emission study, showing notable emission current in a moderateturn-on field, demonstrates potential applications of such ZnO nanoneedle arrays infield emission display devices. The formation of such a ZnO nanoneedle array isattributed to the formation of {0001}-oriented ZnO nuclei on the oriented goldcoated silicon substrate and preferential growth along .