Fabrication of a graphene-based pressure sensor by utilising field emission behavior of carbon nanotubes

In this paper, a miniature graphene-based field emission pressure sensor is reported for the first time, in which carbon nanotubes have been applied as the cathode and reduced graphene oxide sheets have been utilized as the flexible anode. Since, graphene is the thinnest (one atom thick) known structure with a uniform thickness, graphene based membrane is a promising candidate for pressure sensors which allows both high sensitivity and very small chip area, simultaneously. A maximum sensitivity of about 21.9μA/A/Pa is achieved at the bias voltage of 5 V for the fabricated field emission pressure sensor, which is about two orders of magnitude higher than the previously reported graphene based pressure sensors. The fabricated structure has been also used as a graphene based resonator in which emission current is applied to detect the mechanical resonance, efficiently. The measured resonance frequency is measured about 10 MHz, which is shifted to lower frequencies by increasing the ambient pressure. The measured sensitivity, for the resonant operation mode, is about 11.32 Hz/Pa (S = Δf/ΔP). Owing to the inherent low mass of graphene, the presented structure can be entitled as a promising resonant pressure sensor.