Exploiting Metal Coating of Carbon Nanotubes for Scanning Tunneling Microscopy Probes

By exploiting the metal coating of carbon nanotube (CNT) tips for a scanning tunneling microscope (STM), we demonstrated atomic imaging/spectroscopy and showed their potential for electrical nanoprobes. A CNT glued to a W tip was uniformly coated with a thin W layer 3–6 nm thick. Using this tip, stable atomic imaging and spectroscopy were carried out on clean Si(111)-7×7 and Si(100)-2×1 surfaces. The mechanical flexibility of the coated CNT was maintained by virtue of the thin-layer coating, enabling repeated direct contact to the sample surface. Two W-coated CNT tips were brought together within a distance of approximately 50 nm. These results indicate that the tips are useful for electronic transport measurements on a nanometer scale after installation into a multiprobe STM.