Gold overcoatings on spindt-type field emitter arrays

The electron emission properties of a Spindt-type field emitter array have been measured before and after deposition of approximately 100 Angstrom of gold. The workfunction of the emitter decreased by 5% after gold deposition resulting in an 11% reduction in turn-on voltage. Emission stability as measured by RMS current noise improved by 40%. Improvements in emission do not withstand exposure to air. However, baking at moderate temperatures (200 degrees C) restores the emission improvements obtained with the gold overcoating. Fowler-Nordheim plots show that the enhanced emission after baking is due to a increase of the Fowler-Nordheim intercept and not a decrease in slope. Additionally, the gold over coatings resist poisoning as a 50,000 L dose of oxygen only slightly affects emission.