Field emission study of urchin like nanostructured cobalt oxide films prepared by pulsed laser deposition

Cobalt oxide (Co3O4) urchin structures have been grown via Pulsed Laser Deposition (PLD) technique followed by thermal treatment in air. Morphological and structural analysis of as synthesized nanostructures has been carried out using Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD) technique. Chemical nature of the films have been revealed using X-ray Photoelectron Spectroscopy (XPS). Field emission measurements were carried out at a base pressure of 1 × 10−8 mbar. Turn-on field corresponding to an emission current density of 10 μA/cm2 was found to be 3 V/μm and a high field enhancement factor of ∼3900 was estimated, both of which can be attributed to radially grown nanowires of long length with sharp tips. Overall good field emission current stability was observed for Co3O4 urchin structured films. Dependence of FE properties such as, current density and current stability on morphology and density of emitting sites has been observed and analyzed systematically. The observed FE results demonstrate Co3O4 urchin structures as potential candidate for applications in various vacuum micro/nanoelectronic devices.