Enhanced Electron Field Emission of One-Dimensional Highly Protruded Graphene Wrapped Carbon Nanotube Composites

We report the enhanced field emission studies of one-dimensional highly wrinkled graphene wrapped carbon nanotubes measured at a base pressure of 10 –6 mbar. The combined advantage of high aspect ratio and protruded graphene layers on CNT surface are envisioned to improve the field emission current density. Furthermore, the emission characteristics are precisely studied by decorating metal/metal oxide (M/MO like Ru, ZnO, and SnO 2 ) nanoparticles over GWCNTs. It was found that the incorporation of M/MO NPs lowers the work function, which leads to easy electron tunneling and considerably improves the FE performance. The results depict the best FE performance for Ru-GWCNTs based emitters, with a turn-on field of 0.61 V/μm, a current density of 2.5 mA/cm 2 at a field of 1 V/μm, and a field enhancement factor of 6958. The enhanced FE behavior of GWCNTs based emitters is attributed to the easy electron tunneling from the protrusions created on CNT surface which increases the emission sites and hence the FE current density. In addition, the surface decorated M/MO NPs could lower the work function, which contributes to local field enhancement, and hence the low turn-on field. This high performance results for GWCNTs based field emitters are potentially useful for design, fabrication, and optimization of field emission devices.