The fabrication of carbon nanotube probes utilizing ultra-high vacuum transmission electron microscopy

An application of ultra-high vacuum transmission electron microscopy (UHV TEM) is demonstrated for the fabrication of carbon nanotube (CNT) probes. In this study, all the fabrication processes—such as CNT attachment, CNT orientation manipulation, and apex trimming—are integrated into a single UHV TEM system. The in situ work under UHV conditions (<5 × 10−10 mbar) allows us to clean the tip surface at the start of the fabrication process to ensure a good contact between the tip and CNT. Furthermore, the CNT size can be user-selected to meet the various needs for scanning probe microscopy (SPM). Most importantly, the in situ trimming enables a multi-walled CNT to have the sharpness of a single-walled CNT. The three advantages mentioned above are designed to improve conventional methods and will be shown in detail as the procedures of CNT probe fabrication by a series of high-resolution TEM images. Finally, we compare the scanned image via our CNT probes and conventional probes, where the typical artefacts coming from the conventional ones are addressed. We believe the technique we have developed here will further enhance the resolution of SPM measurements.