Highly enhanced field emission from copper oxide nanoparticle decorated vertically aligned carbon nanotubes: Role of interfacial electronic structure
Field emission (FE) properties of Copper (3 nm and 10 nm) decorated vertically aligned carbon nanotubes (VACNTs) grown on Si substrate before and after oxidation are investigated. The current density is found to be the maximum (20 mA/cm2) for 3 nm thick Cu decorated VACNTs after oxidation. The variation in conventionally monitored FE parameters like work function and field enhancement factor cannot explain the experimentally determined high FE current density and its variation. A critical analysis of the electronic structure reveals that the ratio of CuO/Cu2O on VACNTs plays an important role in controlling the FE current density. The highly enhanced FE current density and its temporal stability of 3 nm Cu decorated VACNTs after oxidation indicate that it may be used as a potential material for a FE electron source in future vacuum microelectronic devices.