Enhanced field emission properties from graphene-TiO2/DLC nanocomposite films prepared by ultraviolet-light assisted electrochemical deposition

The graphene-TiO2/diamond-like carbon (G-TiO2/DLC) nanocomposite films were prepared on silicon substrates by a simple ultraviolet (UV) light assisted electrochemical deposition process using N, N-dimethylformamide (DMF) as carbon source and TiO2 nanoparticles/graphene sheets as incorporated reagents. The results show that the TiO2 and graphene sheets are uniformly dispersed into the DLC matrix. The UV-light illumination not only affects the morphology of the films, but also promotes the field emission properties, probably due to the effect of photoinduced electron-hole pairs produced from TiO2. The G-TiO2/DLC film exhibits the lowest turn-on field of 5.2 V/μm and the highest current density of 2950 μA/cm2 at the electric field of 8.2 V/μm. This enhancement of field emission properties are investigated based on the surface morphology of the self-assembled nanostructures, the improved conductivity, together with the reduced work function.