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

• DOI: 10.1016/j.micron.2014.03.005
• Publication Date: 2014-03-20T05:46:19Z
• Authors: Ludvig de Knoop; Florent Houdellier; Christophe Gatel; Aurélien Masseboeuf; Marc Monthioux; Martin Hÿtch
• Keywords: [PHYS]Physics [physics]; 02 engineering and technology; 0210 nano-technology; 7. Clean energy

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.