3D nanorobotic manipulations of multi-walled carbon nanotubes

Abstract

Multi-walled carbon nanotubes (MWNTs) are manipulated in 3D space with a 10-DOF nanorobotic manipulator, which is actuated with PZTs and Picomotors/sup TM/ (New Focus Inc.) and operated inside a scanning electronic microscope (SEM). The coarse linear resolutions of the manipulator are better than 30 nm (X, Y, Z stages actuated by Picomotors) and the rotary one 2 mrad, while the resolutions of fine motions (actuated by PZTs) are within nano-order. AFM cantilevers are used as the end-effector. Several kinds of manipulations of MWNTs are performed with the developed manipulators with the assistance of dielectrophoresis and van der Waals forces. A single MWNT with estimated dimensions of /spl phi/ 40 nm /spl times/7 /spl mu/m has been picked up on an AFM cantilever. Another /spl phi/ 50 nm /spl times/6 /spl mu/m MWNT is placed between two cantilevers, and still another /spl phi/ 40 nm /spl times/8 /spl mu/m MWNT is bent between a cantilever and sample substrate. Carbon nanotube (CNT) junctions are basic building blocks for more complex devices based on CNTs. A cross-junction was constructed with two MWNTs of dimensions of /spl sim//spl phi/ 40 nm /spl times/6 /spl mu/m and /spl sim//spl phi/ 50 nm /spl times/7 /spl mu/m, and a T-junction was made of two MWNTs with the dimensions of /spl sim//spl phi/ 40 nm /spl times/3 /spl mu/m and /spl sim//spl phi/ 50 nm /spl times/2 /spl mu/m. Force measurements are performed and the flexural rigidity and Young's modulus of an /spl sim//spl phi/ 30 nm /spl times/7 /spl mu/m MWNT are estimated to be 8.641/spl times/10/sup -20/ Nm/sup 2/ and 2.17 TPa respectively. Such manipulations are essential for both the property research of CNTs and the fabrication of CNT-based NEMS.