New probes based on carbon nano-cones for scanning probe microscopies

Ultramicroscopy. 2023 Mar:245:113667. doi: 10.1016/j.ultramic.2022.113667. Epub 2022 Dec 18.

Abstract

All-graphenic carbon morphologies grown on individual carbon nanotubes (CNTs) consisting of short-fiber segments bearing sharp micro-/nano-cones at both ends were mounted as new probes for scanning probe microscopies (SPM). Three mounting procedures were tested, two based on focused ion and/or electron beam processes operated in scanning electron microscopes, and another based on an irradiation-free procedure under an optical microscope. The benefits and drawbacks of all the methods are described in details. The extent to which the structural integrity of the carbon material of the cones was affected by each of the mounting processes was also investigated using Raman spectroscopy and high-resolution transmission electron microscopy. The carbon cones were found to be sensitive to both ion and electron irradiation to an unusual extent with respect to structurally-close nano-objects such as multi-wall CNTs. This was assumed to be due to the occurrence of a large number of free graphene-edges at the cone surface. The suitability of such carbon cones as SPM probes is demonstrated, the characteristics of which make them potentially superior to Si-, diamond-, or CNT-probes.

Keywords: Carbon cone; Focused ion beam processes; Graphene; Irradiation damages; Micromanipulator; Scanning probe microscopy.