IOP PUBLISHING NANOTECHNOLOGY Nanotechnology 18 (2007) 345501 (7pp) doi:10.1088/0957-4484/18/34/345501 A carbon nanofibre scanning probe assembled using an electrothermal microgripper K Carlson 1 , K N Andersen 1 , V Eichhorn 2 , D H Petersen 1 , K Mølhave 1 , I Y Y Bu 3 , K B K Teo 3 , W I Milne 3 , S Fatikow 2 and P Bøggild 1 1 MIC-Department of Micro and Nanotechnology, NanoDTU, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark 2 Division Microrobotics and Control Engineering, University of Oldenburg, 26111 Oldenburg, Germany 3 Electrical Engineering Building, Cambridge University Engineering Department, 9 J J Thomson Avenue, Cambridge CB3 0FA, UK E-mail: boggild@mic.dtu.dk Received 14 May 2007, in final form 13 June 2007 Published 27 July 2007 Online at stacks.iop.org/Nano/18/345501 Abstract Functional devices can be directly assembled using microgrippers with an in situ electron microscope. Two simple and compact silicon microgripper designs are investigated here. These are operated by electrothermal actuation, and are used to transfer a catalytically grown multi-walled carbon nanofibre from a fixed position on a substrate to the tip of an atomic force microscope cantilever, inside a scanning electron microscope. Scanning of high aspect ratio trenches using the nanofibre supertip shows a significantly better performance than that with standard pyramidal silicon tips. Based on manipulation experiments as well as a simple analysis, we show that shear pulling (lateral movement of the gripper) is far more effective than tensile pulling (vertical movement of gripper) for the mechanical removal of carbon nanotubes from a substrate. M This article features online multimedia enhancements (Some figures in this article are in colour only in the electronic version) 1. Introduction Carbon nanotubes (CNTs) and nanofibres (CNFs) are high aspect ratio structures with excellent mechanical properties. Through the use of catalytic growth, these structures can be precisely (in terms of position and dimensions) grown on a flat substrate [1, 2]. As with semiconducting nanowires, epitaxial growth enables these structures to be engineered with atomic precision [3, 4]. Carbon nanotubes are already commercially available as scanning probe tips, and for large-scale production of such probes, schemes for wafer-scale assembly or growth of carbon nanotubes and nanofibres directly on the microcantilever has been explored by several groups [5]. Two-dimensional (2D) arrays of CNT/CNFs are straightforward to create by defining catalytic metal particles with electron-beam lithography [1] or nanoimprint [6], followed by plasma-enhanced chemical vapour deposition (PECVD) [1]. The integration of nanotubes, nanofibres and nanowires on microcantilevers and more complex three-dimensional structures requires more elaborate schemes to maintain good control over the position, dimensions and orientation of the structures [7], due to the difficulty of performing lithography on non-flat surfaces. Nanomanipulation using single or multiple tool tips provides a flexible alternative towards integration. Although it is less suitable for mass fabrication, it is a route to transfer a variety of structures to a micro-electro-mechanical system 0957-4484/07/345501+07$30.00 1 © 2007 IOP Publishing Ltd Printed in the UK