Direct pressure sensing with carbon nanotubes grown in a micro-cavity

Abstract

We report on the growth of multiwall carbon nanotubes (CNTs) at the centre of a bow tie micro-cavity and describe the change in resistance of these CNTs under gas pressure loading (ΔR/R ≅ 16%/atm). By adapting the Euler-Bernoulli theory of beams to CNTs that bridge opposite walls of the cavity, we fit the piezoresistance curves and extract the Young's modulus, the piezoresistive constant, and the nanotube radius, for a range of CNT growth conditions. By detecting pressures as low as 0.1 atm, we demonstrate a membrane-less technology capable of sensing pressure with micron scale resolution.