Tunneling characteristics of silicon covered molybdenum tip apex

Abstract

The variation of field emission characteristics of Mo tip apexes by the adsorbed Si atoms was investigated with an instrument combined of an atom probe and a field emission electron spectrometer. The Si/Mo surfaces were also examined using the scanning tunneling microscope/spectrometer. The deposited silicon was found to form microclusters on the Mo substrate and exhibit the semiconductive electronic states which are retained even at the Si–Mo interface where Si and Mo atoms coexist. Heating the Si/Mo surfaces results in the formation of silicides with metallic states. While the work functions of the Si clusters are about 10% larger than the Mo substrate, the silicide work functions are nearly 10% smaller than that of Mo.