Graphene-based structure, method of suspending graphene membrane, and method of depositing material onto graphene membrane

Abstract

An embodiment of a method of suspending a graphene membrane on a support structure includes attaching graphene to a substrate. A pre-fabricated support structure having the gap is attached to the graphene. The graphene and the pre-fabricated support structure are then separated from the substrate which leaves the graphene membrane suspended on the pre-fabricated support structure. An embodiment of a method of depositing material includes placing a support structure having a suspended graphene membrane under vacuum. A precursor is adsorbed to a surface of the graphene membrane. A portion of the graphene membrane is exposed to a focused electron beam which deposits a material from the precursor onto the graphene membrane. An embodiment of a graphene-based structure includes a support structure having a gap, a graphene membrane suspended across the gap, and a material deposited in a pattern on the graphene membrane.

1 . A method of suspending a graphene membrane on a support structure comprising:
 attaching graphene to a substrate;   attaching a pre-fabricated support structure having the gap to the graphene;   separating the graphene and the pre-fabricated support structure from the substrate which leaves the graphene membrane suspended on the pre-fabricated support structure.   
     
     
         2 . The method of  claim 1  further comprising separating the graphene from bulk graphite prior to attaching the graphene to the substrate. 
     
     
         3 . The method of  claim 1  wherein attaching the pre-fabricated support structure comprises:
 placing a pre-fabricated support structure having the gap on the graphene; 
 immersing the pre-fabricated support structure and the graphene in a solvent; and 
 evaporating the solvent which attaches the pre-fabricated support structure to the graphene. 
 
     
     
         4 . The method of  claim 1  wherein attaching the graphene to the substrate comprises attaching the graphene to a sacrificial surface of the substrate. 
     
     
         5 . The method of  claim 4  separating the graphene and the pre-fabricated support structure from the substrate comprises etching the sacrificial surface by immersing the sacrificial surface and the graphene in an etch solution. 
     
     
         6 . The method of  claim 5  wherein the sacrificial surface comprises silicon dioxide. 
     
     
         7 . The method of  claim 6  wherein the etch solution comprises potassium hydroxide. 
     
     
         8 . The method of  claim 5  wherein the sacrificial surface comprises polymethyl methacrylate. 
     
     
         9 . The method of  claim 8  wherein the etch solution comprises an organic solvent. 
     
     
         10 . The method of  claim 9  wherein the organic solvent is selected from the group consisting of acetone and methylpyrrolidone. 
     
     
         11 . The method of  claim 1  wherein separating the graphene and the pre-fabricated support structure from the substrate comprises placing a solvent adjacent to an edge of the pre-fabricated support structure which expands beneath the pre-fabricated support structure and the graphene and which causes the pre-fabricated support structure with the graphene membrane suspended across the gap to release from the substrate. 
     
     
         12 . The method of  claim 1  wherein attaching the pre-fabricated support structure to the graphene comprises:
 applying an adhesive to a surface of the pre-fabricated support structure; and 
 bringing the adhesive into contact with the graphene. 
 
     
     
         13 . The method of  claim 12  wherein separating the graphene and the pre-fabricated support structure from the substrate comprises pulling the pre-fabricated support structure which leaves the graphene attached to the pre-fabricated support structure by the adhesive. 
     
     
         14 . The method of  claim 13  further comprising immersing the graphene and the pr-fabricated support structure in a solvent which removes excess adhesive. 
     
     
         15 . The method of  claim 1  further comprising heating the pre-fabricated support structure having the graphene membrane suspended across the gap after separating the pre-fabricated support structure and the graphene membrane from the substrate. 
     
     
         16 . The method of  claim 1  wherein the pre-fabricated support structure comprises a TEM grid. 
     
     
         17 . The method of  claim 1  wherein:
 the pre-fabricated support structure comprises a plurality of gaps; and 
 separating the graphene and the pre-fabricated support structure from the substrate leaves the graphene membrane suspended across at least two of the gaps in the pre-fabricated support structure. 
 
     
     
         18 . The method of  claim 1  wherein attaching the pre-fabricated support structure to the graphene further comprises attaching the pre-fabricated support structure to the substrate beyond where the pre-fabricated support structure attaches to the graphene. 
     
     
         19 . A method of depositing material comprising;
 placing a support structure having a graphene membrane suspended on said support structure under vacuum;   adsorbing a precursor to a surface of the graphene membrane; and   exposing a portion of the graphene membrane to a focused electron beam which deposits a material from the precursor onto the graphene membrane.   
     
     
         20 . The method of  claim 19  wherein adsorbing the precursor to the surface of the graphene membrane takes place prior to, while, or after placing the support structure having the graphene membrane under the vacuum. 
     
     
         21 . The method of  claim 19  wherein exposing the portion of the graphene membrane to the focused electron beam deposits amorphous carbon onto the graphene membrane. 
     
     
         22 . The method of  claim 19  wherein exposing the portion of the graphene membrane to the focused electron beam deposits a dopant onto the graphene membrane. 
     
     
         23 . The method of  claim 19  further comprising raster scanning the electron beam across the graphene membrane to produce a pattern of the material on the graphene membrane. 
     
     
         24 . The method of  claim 23  wherein the pattern forms an electronic device on the graphene membrane. 
     
     
         25 . The method of  claim 23  wherein the pattern forms a plurality of local perturbations on a nanometer scale. 
     
     
         26 . The method of  claim 23  wherein the pattern forms an etch mask for further processing of the graphene membrane. 
     
     
         27 . An graphene-based structure comprising:
 a support structure having a gap;   a graphene membrane suspended on said support structure; and   a material deposited in a pattern on the graphene membrane.   
     
     
         28 . The method of  claim 27  wherein the material comprises amorphous carbon. 
     
     
         29 . The method of  claim 27  wherein the pattern comprises a feature dimension of less than about 2.5 nm.