Electromechanical properties of single-walled carbon nanotube devices on micromachined cantilevers

Abstract

We have investigated the electromechanical properties of single-walled carbon nanotubes (SWNTs) by constructing carbon nanotube transistors on micro-cantilevers. SWNTs and ultra-long carbon nanotubes (UNTs) were grown on free-standing Si 3 N 4 membranes by using chemical vapor deposition, and electrical contacts were generated with electron beam lithography and lift-off. The cantilevers bearing SWNT devices were micromachined so that hybrid cantilevers with various spring constants were fabricated. To measure the electromechanical properties of the SWNTs, precisely controlled forces were generated by a microbalance and applied to the hybrid cantilever devices. Upon bending, the conductances of the metallic and large-gap semiconducting UNTs showed no notable change, whereas the conductances of the small-gap semiconducting UNTs and networks of SWNTs increased. Numerical simulations of bended SWNT made using a multiscale simulator supported the hypothesis that the small-gap semiconducting SWNTs undergo a metallic transformation upon bending.

Flexible Carbon Nanotube Films for High Performance Strain Sensors

“…Tips from atomic force microscopy (AFM) were used to deflect suspended individual SWCNT and caused a decrease of two orders of magnitude of conductivity due to the formation of local sp 3 bonds between tube and tip [28]. When applying reversible deformations and compressive strains (bending) on individual SWCNTs with an AFM tip alterations of the band gap and the conductivity were observed [29]. A strain gauge was theoretically predicted by the tight-binding approach and for SWCNTs with diameter larger than 1 nm it was found to be chirality dependent [30].…”

Recent Advances on SEM-Based In Situ Multiphysical Characterization of Nanomaterials

“…The last two decades have witnessed the extensive research on nanomaterials because of their exceptional promise in science and technology. Based on structural dimension, existing nanomaterials fall into four categories of nanostructures: zero-dimensional structures (e.g., nanoparticles, nanospheres, and isolated molecules) [ 1 ], one-dimensional structures (e.g., nanowires, nanobelts, nanotubes, and nanoribbons) [ 2 – 4 ], two-dimensional structures (e.g., nanofilms, grapheme, and molybdenum disulfide) [ 5 , 6 ], and three-dimensional structures (e.g., nanocombs, nanoflowers, and nanocups) [ 7 – 9 ]. Due to their superior physical properties and unique nanoscale morphologies, these nanomaterials have been widely used for a variety of applications such as next-generation electronics [ 10 ], sustainable energy [ 11 ], biosensing [ 12 ], and (opto) electronics [ 13 ].…”