Fabrication and behavior of nanoscale field emission structures

Novel field emission devices with dimensions an order of magnitude less than the elastic mean free path of electrons in air have been fabricated and tested at atmospheric pressure. It is well known that the operating voltage of field emission devices may be decreased by reducing the radius of the emitter tip and the distance between the emitter tip and extractor electrode. We have developed and tested a nanoscale-tip field emission system consisting of multiple emitter tips with radii of about 1 nm within an extractor aperture 50 nm in diameter. All nanopillar tips were less than 30 nm from the extractor electrode in both the horizontal and vertical directions, so field-emitted electrons traveled ballistically from the nanopillar tips to the extractor electrode even at atmospheric pressure. The extractor turn-on voltage was approximately 7 V; field-emitted currents of about 10 nA were collected typically at an extractor voltage of 9 V. (C) 1997 American Vacuum Society.