Low Voltage, High Current Nanoscale Si Field Emission Arrays for Operation in Air

This phase I SBIR proposal addresses development of low voltage ( few µms. We propose application of nanofabrication methods to form closely spaced arrays of Si field emitters (tips and wedges). Using reactive ion etching, wet-chemical etching, and hermal oxidation, the tip radius is reduced to ~ few nms and cathode-anode separation to ~ 50-250 nm range. Since, the mean free path of electrons in air is ~ 250 nm, this separation coupled with emitter radius will allow low-voltage operation in air at high current. Vertical and lateral field emission devices are proposed. Wherass vertical devices use conventional nanofabrication methodology, the lateral device configuration incorporates an innovative configuration comprising of vertically stacked independently controlled emitters to significantly enhance current per unit area. Finally, these structures can serve as templates for cold cathode emitters by suitable deposition of metal and removal of Si.