Determining the work function of a carbon-cone cold-field emitter by in situ electron holography

Ludvig de Knoop , Florent Houdellier (1) , Christophe Gatel (1) , Aurélien Masseboeuf (2, 3) , Marc Monthioux (1) , Martin Hÿtch (1)

1 CEMES - Centre d'élaboration de matériaux et d'études structurales
2 LEMMA - Laboratoire d'Etude des Matériaux par Microscopie Avancée
3 SP2M - UMR 9002 - Service de Physique des Matériaux et Microstructures

Cold-field emission properties of carbon cone nanotips (CCnTs) have been studied in situ in the transmission electron microscope (TEM). The current as a function of voltage, i(V), was measured and analyzed using the Fowler–Nordheim (F–N) equation. Off-axis electron holography was employed to map the electric field around the tip at the nanometer scale, and combined with finite element modeling, a quantitative value of the electric field has been obtained. For a tip-anode separation distance of 680 nm (measured with TEM) and a field emission onset voltage of 80 V, the local electric field was 2.55 V/nm. With this knowledge together with recorded i(V) curves, a work function of 4.8 ± 0.3 eV for the CCnT was extracted using the F–N equation.

Domaines: Physique [physics]

Ludvig de Knoop, Florent Houdellier, Christophe Gatel, Aurélien Masseboeuf, Marc Monthioux, et al.. Determining the work function of a carbon-cone cold-field emitter by in situ electron holography. Micron, 2014, 63, pp.2--8. ⟨10.1016/j.micron.2014.03.005⟩. ⟨hal-01430588⟩