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

Abstract

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 x 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.

Lattice-resolved frictional pattern probed by tailored carbon nanotubes

“…Therefore, the well-known high-aspect-ratio carbon nanotube (CNT) probe should be a convenient candidate to solve the bluntness problem. Our recent technique has outlined a routine process to fabricate high-quality CNT probes with the telescope shape, which have reduced the typical artifacts found in the tapping-mode AFM measurement using a conventional longer and softer CNT probe [6]. When applied to the LFM measurement, the much stronger tip-sample interaction due to the contact will further disadvantage the use of a flexible CNT.…”

“…When the current reached ∼10 μA, the heat accumulated at roughly the central position burned the CNT off. The complete procedures of CNT probe fabrication were conducted in our UHV transmission electron microscope (TEM) (JEOL JEM-2000V) and described in [6].…”

“…Here, we evidently produced an atomically flat closed cap to achieve a single asperity, with a well-defined periodic surface, which allows the complete contact on another atomically flat surface. This closed cap was elaborated by letting the gold STM tip (figure 1) fully touch a user-selected CNT end [6] to slowly burn its length, roughly at a rate of 10 nm per 10 min, the process of which is recorded in video 1 (available at stacks.iop.org/Nano/21/055702/mmedia). By the deliberate control of the conducting current, it allows the heated carbon atoms to have enough kinetic energy to form the most stable structure at the cap region.…”

Multi‐wall carbon nanotubes by catalytic decomposition of carbon monoxide on Ni/MgO

“…[1][2][3] Multi-walled carbon nanotube (MWCNT), which has superior mechanical properties compared to single-walled carbon nanotube (SWCNT), are applied to various industries like nanotube composites, STM, AFM, EFM tips, and biomaterial. 4 The various methods for CNT synthesis have been introduced such as chemical vapor deposition (CVD), electric arc discharge, and laser evaporation. [5][6][7] Catalytic chemical vapor deposition is known as the most promising one, since it can produce high-quality nanotubes using catalytic reaction with the decomposition of hydrocarbons and the disproportionation of carbon monoxide.…”

Orientation-dependent friction between a carbon nanotube and graphite

“…12 The third key feature we added to our system is the attachment of a carbon nanotube (CNT) to the modified commercial AFM pyramidal probe. This process was carried out in our ultrahigh vacuum transmission electron microscope and scanning tunneling microscope (UHV TEM-STM) combined system, 13 and the tube probe, displayed in Fig. 1(c), is usually short and inclined to a side.…”