High-Yield Large-Scale\nSuspended Graphene Membranes\nover Closed Cavities for Sensor Applications

Suspended membranes of monatomic graphene exhibit great\npotential\nfor applications in electronic and nanoelectromechanical devices.\nIn this work, a “hot and dry” transfer process is demonstrated\nto address the fabrication and patterning challenges of large-area\ngraphene membranes on top of closed, sealed cavities. Here, “hot”\nrefers to the use of high temperature during transfer, promoting the\nadhesion. Additionally, “dry” refers to the absence\nof liquids when graphene and target substrate are brought into contact.\nThe method leads to higher yields of intact suspended monolayer chemical\nvapor deposition (CVD) graphene and artificially stacked double-layer\nCVD graphene membranes than previously reported. The yield evaluation\nis performed using neural-network-based object detection in scanning\nelectron microscopy (SEM) images, ascertaining high yields of intact\nmembranes with large statistical accuracy. The suspended membranes\nare examined by Raman tomography and atomic force microscopy (AFM).\nThe method is verified by applying the suspended graphene devices\nas piezoresistive pressure sensors. Our technology advances the application\nof suspended graphene membranes and can be extended to other two-dimensional\nmaterials.