Determining the work function of a carbon-cone cold-field emitter by in situ electron holography.
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.
CEMES-CNRS, Université de Toulouse, 29 rue Jeanne Marvig, 31055 Toulouse, France. Electronic address: deknoop@cemes.fr.
Ludvig
L
de Knoop
CEMES-CNRS, Université de Toulouse, 29 rue Jeanne Marvig, 31055 Toulouse, France. Electronic address: florent@cemes.fr.
Florent
F
Houdellier
CEMES-CNRS, Université de Toulouse, 29 rue Jeanne Marvig, 31055 Toulouse, France. Electronic address: gatel@cemes.fr.
Christophe
C
Gatel
CEMES-CNRS, Université de Toulouse, 29 rue Jeanne Marvig, 31055 Toulouse, France. Electronic address: aurelien.masseboeuf@cemes.fr.
Aurélien
A
Masseboeuf
CEMES-CNRS, Université de Toulouse, 29 rue Jeanne Marvig, 31055 Toulouse, France. Electronic address: marc.monthioux@cemes.fr.
Marc
M
Monthioux
CEMES-CNRS, Université de Toulouse, 29 rue Jeanne Marvig, 31055 Toulouse, France. Electronic address: martin.hytch@cemes.fr.
Martin
M
Hÿtch
Electron holography; Field emission of carbon; Finite element modeling; In situ TEM