Low-macroscopic field emission from fibrous ZnO thin film prepared by catalyst-free solution route

Fiber-structured zinc oxide thin films were synthesized by catalyst-free chemical process from zinc acetate dihydrate at an elevated temperature of 1073 K on Si substrate. X-ray diffraction spectra confirmed the proper phase formation of the films. Scanning electron micrograph depicted the formation of ZnO fibers with an average diameter of 500 nm with an average aspect ratio 150. Field emission properties of the film showed considerably low turn-on field around 1.4 V/mm. This low-threshold field-emission of the films are attributed to the conducting nanostructure inside the film as well as on the tip of the fibers at the film–vacuum interface, which causes the geometrical field enhancement at the emitter-tip and provides the required barrier field for field-emission tunneling. The emission current was as high as 70 mA at the field of 3.6 V/mm. The high emission current, high stability and low turn-on field make the ZnO fibers a strong candidate for field-emission displays.