GOLD DEPOSITION FROM A SCANNING TUNNELING MICROSCOPE TIP

We have demonstrated that a gold scanning tunneling microscope (STM) tip can be used as a miniature solid-state emission source for directly depositing nanometer-size gold structures. The process has been demonstrated in ultrahigh vacuum on gold substrates, and in air on gold and platinum substrates. Studies made in air suggest that the process is fast, repeatable, and field-induced. The emission mechanism is believed to be field evaporation of tip atoms, which is enhanced by the close proximity of the substrate. The technique has been used to write several thousand features with no apparent degradation of the tip's ability to write. Elevated and room temperature studies show the written structures to be stable over periods of weeks, in contrast to some previous STM measurements of gold self-diffusion.