Characterization of InSb nanopillars for field emission applications

A piezoelectrically driven metallic nanoprobe is installed inside a scanning electron microscope to perform local characterization of the field emission properties of InSb nanopillars. The tip-shaped anode can be precisely positioned at sub-micron distances from the emitters to collect electrons from areas as small as 1µm2 under the application of an external bias up to 100 V. Current-voltage characteristics are measured for cathode-anode separation down to 500 nm and are analyzed in the framework of the Fowler-Nordheim theory. We give estimation of performance parameters such as the field enhancement factor and the turn-on field and their dependence on the cathode-anode separation distance. We demonstrate the time stability of the emitted current for several minutes. Finally, we perform a finite element electrostatic simulation to calculate the electric field in proximity of the nanopillars and we evaluate the effective emitting area as well as the screening effect due to presence of other pillars in close vicinity. We show that InSb nanopillars are very stable emitters that allow current density as high as 104 A/cm2 and excellent time stability, crucial characteristics to envisage device exploitation.