Fig. 1: Different types of graphene ribbons with suspended Si proof masses.

a–c 3D schematics of the device design of two graphene ribbons with a suspended Si mass, four ribbons (cross) with a suspended Si mass, four ribbons (parallel) with a suspended mass. d–g Flow diagram of device fabrication: (d) the trenches were etched in the thermally oxidized silicon device layer of the SOI wafer thereby forming the Si mass; (e) the section of handle layer of the SOI wafer was etched by DRIE to expose BOX layer to air; (f) the double-layer graphene was integrated to the pre-fabricated SOI substrate by wet transfer method and etched into different types of ribbon structures by optical lithography and O₂ plasma etching; (g) the oxidized Si proof mass was released by removing the BOX layer of the SOI substrate using RIE followed by vapour HF. h–j Top view of SEM images of three types of fabricated graphene ribbon devices: (h) two ribbons with a suspended Si mass; (i) four crossed ribbons with a suspended Si mass; and (j) four parallel ribbons with a suspended Si mass