Given the much greater prevalence of conventional AFM relative to CD-AFM, most of the research into CNT tips has involved conventional AFM. The ability to image near-vertical sidewalls is the central feature of CD-AFM, and this geometrical requirement means that the constraints on the CNT orientation for a useful tip are even greater than for conventional AFM tips. However, there has been progress in the application of CNT tips to CD-AFM by a number of researchers.22,24 The considerably greater wear resistance of CNT tips has also been demonstrated in this context.