A gas sensor made from a graphite paper with a nanotube film

Abstract

A technique for obtaining gas sensor samples from graphite paper with a nanotube film is described. Current-induced annealing of the graphite paper and additional evaporation of a nanotube graphite film in a hydrogen atmosphere are combined in the developed technique. The current−voltage characteristics of the samples have been measured at room temperature in air, in vacuum, and at low concentrations of NH₃, ethanol, and acetone. Experiments demonstrate that these samples containing carbon multiwall nanotubes can be used as a gas sensor to detect the presence of NH₃ and acetone. They are characterized by high sensitivity and selectivity, fast response, restoration, and stability of the characteristics. The estimated sensor sensitivities to NH₃, acetone, and ethanol at a current of 96.8 mA are ~15, ~12, and ~1 mV/Torr, respectively. Their sensitivity is determined by the difference in the behavior of their current−voltage characteristics under exposure to NH₃, ethanol, and acetone. The sensor features fast response (5–20 s) and restoration (within 5 min, restoration to the initial state before the exposure to NH₃ is 100.2%), as well as the stability of its characteristics (the pressure ranges from 1 × 10^–6 to 760 Torr).