E L S E V I E R Microelectronic Engineering 46 (1999) 101-104 Manipulation of Carbon Nanotubes and Properties of Nanotube Field-Effect Transistors and Rings IvIICE:)~-~'CTIROlt~ H.R. Shea, R. Martel, T. Hertel, T. Schmidt, and Ph. Avouris* I B M Research Division, T.J. Watson Center, P.O. Box 218, Yorktown Heights, NY 10598, U.S.A. Using the tip o f an atomic force microscope, we have manipulated individual carbon nanotubes on a patterned substrate, and have fabricated model nanodevices, including a room temperature field-effect transistor with a channel only 1.6 nm wide, as well as single-electron transistors. W e have also developed a technique to produce rings o f single-wall nanotubes with a very high yield. 1. I N T R O D U C T I O N Carbon nanotubes (NT) are a novel class of nanostructures consisting of one or several graphene sheets rolled into a single seamless hollow cylinder, or several concentric cylinders, respectively. Depending on the width o f the graphene sheet and the angle at which it is rolled, the N T can be either a semiconductor or a metal. In addition to these intriguing electrical properties, nanotubes have a very high tensile strength and are extremely rigid. Because o f these characteristics, a great number o f applications for NTs have been proposed, such as 1D nanowires and switching elements in nano- devices [1]. In this paper we discuss first the manipulation o f nanotubes on a patterned substrate, then field-effect transistors (FETs) and single-electron transistors (SETs) in which nanotubes are the channel. Finally we demonstrate the capability o f making rings o f nanotubes. 2. M A N I P U L A T I O N There is a strong Van der Waals attraction between nanotubes, and between nanotubes and the substrate they are deposited upon. Because o f the high binding energy with the substrate (~0.8 eV//~ for a 1 0 0 / ~ diameter multi-wall tube [2]) the tube can be pinned in a highly strained (bent) configuration despite its high Young's modulus (~1 TPa). W e can manipulate the N T position at room temperature by applying lateral forces with the tip o f an atomic force microscope (AFM). W e found the shear stress on surfaces such as H-passivated silicon is high, of the order o f 10 7 N/m, such that not only the position but also the shape o f the N T can be controlled [2]. a ) - ~ { ~ , " b ) , , :i:: ::' '::ii~ :~ilili! ~i ~ Fig. 1: AFM manipulation o f a single multi-wall nanotube. Initially the N T is located on an insulating part o f the sample. In a stepwise fashion, it is dragged onto the 80 A high metal thin film wire, and finally stretched across the oxide barrier. 0167-9317/99/$ - see front matter © 1999 Elsevier Science B.V. All fights reserved. PII: S 0 1 6 7 - 9 3 1 7 ( 9 9 ) 0 0 0 2 5 - 8 I02 H.R. Shea et al. / Microelectronic Engineering 46 (1999) 101-104 To perform the manipulation, we alternate between th ...