SI NANOWIRE GROWTH WITH ULTRAHIGH-VACUUM SCANNING-TUNNELING-MICROSCOPY

Using a scanning tunneling microscope (STM), Si nanowires were grown b y applying a voltage at a constant current between a Si substrate and a gold STM tip. Silicon atoms were deposited onto a gold tip by field evaporation. The field evaporation rate of silicon atoms was activated by heating the substrate. Silicon nanowire was grown on the gold tip at a substrate temperature of 700 degrees C. Nanowires could not be gr own on a clean tungsten tip when using a gold-free Si substrate. The p resence of gold atoms is important for the growth of silicon. Apparent ly, gold atoms deposited on the silicon substrate by field evaporation reduce the activation energy of field evaporation by attacking Si-Si bonds. (C) 1997 American Institute of Physics.