Measurement of the Adhesion Energy of Pressurized Graphene Diaphragm Using Optical Fiber Fabry-Perot Interference

Van der Waals adhesion between graphene and substrate has an important impact on the graphene-based sensor performance. Here, we proposed a simple in situ measurement method for the adhesion energy of the graphene diaphragm suspended on the endface of a ferrule. The interaction between the diaphragm and its substrate created a low finesse Fabry-Perot (FP) interferometer. The analytical relationship between prestress and adhesion energy was modeled on the basis of the initial dip along the edges of the suspended regions. Then, the deflection deformations of pressurized graphene diaphragm were examined using the FP interference technology. The obtained adhesion energies for monolayer and two to five layer graphene membranes on SiO₂ conformed exceedingly well to the previously measured results and yielded a cross-correlation coefficient of 0.999 with the latter. Furthermore, an experimental setup for acoustic pressure test was developed to determine the adhesion energies for ~7-layer and ~13-layer graphene diaphragms with a zirconia substrate to be 0.286 and 0.275 J/m², respectively. The highly consistent experimental data confirmed the accuracy of our method. This method presented in this paper could be further extended for measuring the adhesion energy of other 2-D materials.