  Indium arsenide nanowires grown by selective-area vapor phase epitaxy are
used as tips for scanning tunneling microscopy (STM). The STM tips are realized
by positioning the wires manually on the corner of a double cleaved gallium
arsenide wafer with submicrometer precision and contacting them
lithographically, which is fully compatible with further integrated circuitry
on the GaAs wafer. STM images show a z-noise of 2 pm and a lateral stability
of, at least, 0.5 nm on a Au(111) surface. I(z) spectroscopy reveals an
exponential decay indicating tunneling through vacuum. Subsequent electron
microscopy images of the tip demonstrate that the wires are barely modified
during the STM imaging.
