Highly Stable and Sensitive Gas Sensor Based on Single-Walled Carbon Nanotubes Protected by Metal-Oxide Coating Layer

Abstract

We fabricated a highly stable and sensitive gas sensor based on single-walled carbon nanotubes (SWNTs) protected by metal-oxide coating layer. SWNTs were deliberately decorated with 2–5 nm of oxygen-deficient SiOx and AlOx by pulsed laser deposition, followed by annealing under Ar/H2 ambient. Surpassing the as-grown SWNTs, the metal-oxide coated SWNTs showed an excellent sensing stability with a variation of sensor response less than 7–8%. The obtained sensitivity to NO2 was also improved. Moreover, the relationship between NO2 concentration and sensor response can be described by the Frumkin–Temkin isotherm.