High current electron emission from novel semiconductor nanocrystals and related nanostructures

This report details high current field emission from silicon nanostructures, named nanowhiskers. Arrays of nanometer scale whiskers have been grown using the GNS electron beam annealing system. Key growth parameters have been varied to study the influence on field emission characteristics. In almost all cases a field emission current of greater than 1 μA was achieved. Threshold electric fields for current flow over 1 nA ranged from 1.5 to 8 V/μm. Through studying the growth on different substrates we conclude that the electrical parameters of the substrate material does not influence the field emission. Similarly no correlation was observed with the annealing duration. We observed preferable field emission properties from samples grown between 900 and 1000 degrees C (in comparison to higher temperatures). A general correlation was also observed between nanowhisker height and the threshold electric field. Nanowhisker arrays with 3 to 4 nm average height features were preferable for lower emission thresholds and higher output current (greater than 10 μA in some cases). For optimum field emission performance growth parameters of 900-1000 degrees C for 15-60 seconds are recommended. (author). 18 refs., 15 figs., 5 tabs