Research / 2020 / Article / Fig 4

Review Article

Nanoelectromechanical Sensors Based on Suspended 2D Materials

Figure 4

Tension-induced pressure sensor: (a) fabrication method of the suspended membrane (according to Figure 1) and (b) example device [21]. (c–e) Working principle: the gas pressure difference across the membrane causes a membrane deflection and tension change that is measured via the resonance frequency. (f) Graphene tension-induced pressure sensor measurement [21]. Squeeze-film pressure sensor: (g) fabrication of the suspended membrane and (h) example device [175]. (i, j) Working principle: the stiffness and compressibility of the gas under the membrane increases the stiffness of the membrane that is measured via the mechanical resonance frequency. (k) Example measurement of a graphene-based squeeze-film pressure sensor [175]. Graphene Pirani pressure sensor: (l) fabrication of the suspended membrane; (m) example device of a Pirani pressure sensor [132]. (n, o) Working principle: the temperature, and temperature-dependent resistance, of the suspended, Joule-heated graphene beam depends on the pressure-dependent gas cooling rate. (p) Example measurement of a Pirani pressure sensor based on graphene [132].