ZnO Nanowire-Based Field Emission Devices Through a Microelectronic Compatible Route

Abstract

Nanostructured zinc oxide (ZnO) has attracted considerable interest for a wide range of applications, including its use as an active layer in gas sensor devices and as promising emitters for field emission devices. Although it is interesting for FE purposes, the synthesis of this material can be complex and non-compatible with microelectronic processes. To overcome this issue, this paper explores ZnO nanowires growth through thermal oxidation of zinc thin films. We applied this IC-compatible procedure to fabricate field emission cathodes. Analyses of Raman spectroscopy, X‑ray photoelectron spectrometry, X‑ray diffractometry and scanning electron microscopy confirmed that the processes applied were well succeeded in obtaining nanoscale structures of ZnO with dimensions up to 4 micrometers in length and 30‑100 nanometers in diameter. Electrical characterization showed an intense electron field emission on the active area of the device, with a low turn-on electric field (2.4 volts/micrometer). An innovative system based on image processing allowed electrical current mapping throughout the active area of the devices, providing information about the uniformity of the emitted current. These results demonstrate that the low-complex fabrication procedures adopted as well as the ZnO nanomaterial itself are suitable for FE devices development.