This paper demonstrates the application
of a graphene–ferric
oxide (hollow mesoporous α-Fe2O3 microspheres)
nanocomposite for the measurement of vacuum pressure. Numerous research
and industrial systems essentially require a vacuum environment, and
therefore, measurement of vacuum becomes vital for their efficient
functioning. The presented graphene nanocomposite vacuum pressure
sensor (GnVS) is fabricated using a reduced graphene oxide (rGO)/α-Fe2O3 nanocomposite synthesized by a facile and safe
hydrothermal process. This sensor has an impressive operating range
spanning 9 orders of magnitude down from atmospheric pressure (103 mbar) to high vacuum (∼4 × 10–6 mbar), a remarkable sensitivity of 2 × 10–4 mbar–1, and a response/recovery time of ∼3
s, which are major improvements over the reported graphene- and rGO-based
vacuum sensors. The reason behind the exceptional device performance
is proposed to be a coaction of gas chemisorption on sensor surface,
thermal conductivity of the sensing material, and varying van der
Waals force between rGO layers. The temperature dependence of the
sensor has been examined, and an appropriate temperature compensation
technique is suggested. GnVS promises to bring a one-step vacuum measurement
solution with its high sensitivity, repeatability, broad range, simple
cost-effective design, and potential to revolutionize the vacuum sensing
technology.