Speakers
Description
Small surface defects are thought to affect field emission through the field enhancement and modification
of the work function. We combined density functional theory and quantum transport calculations to study
the influence of atomic–scale defects on the work function and field emission characteristics of copper
surfaces. A newly developed general methodology for the calculation of the field emitted current density
from nano-featured surfaces is used to study specific defects on a Cu(111) surface.
Our results show that the inclusion of a defect can significantly locally enhance the field emitted current
density. However, this increase is attributed solely to the decrease of the work function due to the defect,
with the effective field enhancement being minute. Finally, the Fowler–Nordheim equation is found to be
valid when the modified value for the work function is used, with only an approximately constant factor
separating the computed currents from those predicted by the Fowler–Nordheim equation
