Micro-Raman investigation of vanadium-oxide coated tubular carbon nanofibers for gas-sensing applications

Commercial tubular carbon nanofibers were uniformly coated with a 5 nm thick vanadium oxide layer via a modified approach to atomic layer deposition. The composition and microstructure of the resulting hybrid material was analyzed by micro-Raman spectroscopy. The effect of the post-synthesis thermal treatment in air at temperatures in the range of 25-375 °C was investigated in order to more deeply understand the behavior of the hybrid material in gas sensing devices. The obtained results demonstrate that the thermal treatment primarily affects the oxide coating-layer that is responsible for the sensing properties. The best sensor performance was obtained at the temperature at which the oxide layered-structure exhibits the highest structural order.