Batch fabrication of nanotubes suspended between microelectrodes

Abstract

We report a fabrication method, which uses standard UV-lithography to pattern the catalyst for the chemical vapour deposition (CVD) of suspended double clamped single walled carbon nanotubes. By using an aqueous solution of Fe(NO 3) 3 the patterning of the catalyst material onto microelectrodes can be done with a simple lift-off process with standard photolithographic resist. An applied electric field is sustained between the microelectrodes during CVD to guide the nanotube growth. Comparison with simulations shows that the location and the orientation of the grown carbon nanotubes (CNT) correspond to the regions of maximum electric field, enabling accurate positioning of a nanotube by controlling the shape of the microelectrodes. The CNT bridges are deflected tens of nm when a DC voltage is applied between the nanotube and a gate microelectrode indicating that the clamping through the catalyst particles is not only mechanically stable but also electrical conducting. This method could be used to fabricate nanoelectromechanical systems based on suspended double clamped CNTs depending only on photolithography and standard Cleanroom processes.