Field emission properties of ZnO single-crystal microtubes were investigated in this work. The turn-on voltages for the as-grown and postannealed ZnO microtube samples were 5.6 and 6.4 V/μm, respectively. The emission current density was 11 mA/ cm2 at an applied field of 20 V/μm for the as grown ZnO microtube and 12.5 mA/ cm2 at an applied field of 13 V/μm for the postannealed ZnO microtube. Due to the relatively large tip area (in comparison with ZnO nanomaterials) of the ZnO microtubes, the intrinsic field emission enhancement factor Β of the ZnO microtube was comparatively low (estimated to be around 6.5). However, the experimental Β values were quite high (418 for the as-grown ZnO microtube and 1466 for the postannealed ZnO microtube), indicating strong field emission characteristics of the ZnO microtubes.
All Science Journal Classification (ASJC) codes
- General Physics and Astronomy