Graphene diaphragm analysis for pressure or acoustic sensor applications

Graphene has remarkable mechanical properties, and it is a very promising material for sensors. The progress of graphene diaphragm based pressure sensor was detailed firstly. Then the deflection of pressurized circular graphene diaphragm with pre-stress was discussed, an approximate solution was given to substitute Hencky’s series solution. Pre-stress descends the sensitivity of the graphene diaphragm, but it also makes the deflection linear in pre-stress dominated regime, which is important for sensor applications. The pre-stress in the diaphragm caused by van der Waals force between the diaphragm and the sidewall of the substrate was studied, the results indicates that the pre-stress is associated with the adhesion energy per unit area between the diaphragm and sidewall of the substrates, and the thickness of the diaphragm. Due to the influence of the the adhesion force, multilayer (2~10 layers) graphene diaphragms are more sensitive than monolayer, as monolayer graphene is much more flexible, the adhesion energy is higher than multilayer graphene.