Adsorbate-enhanced field-emission from single-walled carbon nanotubes: a comparative first-principles study.

We report a comparative ab initio study of different types of adsorbates and their adsorption mechanism on the field-emission performance of single-walled carbon nanotubes by analyzing electrical properties and transport characteristics and considering the thermal stability of the adsorbed structure. Adsorbates were found to reduce the work function by up to 1.3 eV, enhance tunneling near the carbon nanotube tip, and increase the field-emission current by as much as two orders of magnitude. A significant localization of the electron cloud was also observed near the adsorbates under a high applied electric field.