Nanomechanical resonators made from suspended graphene exhibit high sensitivity toward pressure variations. Nevertheless, these devices exhibit significant energy loss in nonvacuum environments due to air damping, as well as inevitably weak gas leakage within the reference cavity because of the slight permeation of graphene. We present a new type of graphene resonant pressure sensor utilizing micro-opto-electro-mechanical systems technology, which features a multilayer graphene membrane that is sealed in vacuum and adhered to pressure-sensitive silicon film with grooves. This approach innovatively employs an indirectly sensitive method, exhibiting 60 times smaller energy loss in atmosphere, and solving the long-standing issue of gas permeation between the substrate and graphene. Notably, the proposed sensor exhibits a high pressure sensitivity of 1.7 Hz/Pa, which is 5 times higher than the sensitivity of the silicon counterparts. Also, the all-optical encapsulating cavity structure contributes a high signal-to-noise ratio of 6.9 × 10-5 Pa-1 and a low temperature drift (0.014%/◦C). The proposed method offers a promising solution for long-term stability and energy loss suppression of pressure sensors using two-dimensional materials as the sensitive membrane.
Keywords: MOEMS; graphene; pressure sensing; resonators; vacuum sealing.