School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China.
Shenzhen Institute of Beihang University, Shenzhen 518063, China.
ACS Appl Mater Interfaces. 2023 Jun 28;15(25):30479-30485. doi: 10.1021/acsami.3c04520. Epub 2023 Jun 12.
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 Pa 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.
基于悬浮石墨烯的纳米机械谐振器对压力变化表现出很高的灵敏度。然而，由于空气阻尼，这些器件在非真空环境中会损失大量能量，而且由于石墨烯的轻微渗透，参考腔体内不可避免地会发生气体泄漏。我们提出了一种新型的基于微机电系统技术的石墨烯谐振式压力传感器，其采用多层石墨烯膜，密封在真空中，并与带有凹槽的压敏硅膜粘合。这种方法创新性地采用了间接灵敏的方法，在大气中的能量损失小 60 倍，解决了基底与石墨烯之间气体渗透的长期问题。值得注意的是，所提出的传感器具有 1.7 Hz/Pa 的高压力灵敏度，比硅基传感器的灵敏度高 5 倍。此外，全光学密封腔结构具有 6.9×10 Pa 的高信噪比和低温度漂移（0.014%/C）。该方法为使用二维材料作为敏感膜的压力传感器的长期稳定性和能量损失抑制提供了一种很有前途的解决方案。
