Graphene transistor gated by charges through a nanopore for bio-molecular sensing and DNA sequencing

Abstract

A technique for a nanodevice is provided. A reservoir is separated into two parts by a membrane. A nanopore is formed through the membrane, and the nanopore connects the two parts of the reservoir. The nanopore and the two parts of the reservoir are filled with ionic buffer. The membrane includes a graphene layer and insulating layers. The graphene layer is wired to first and second metal pads to form a graphene transistor in which transistor current flowing through the graphene transistor is modulated by charges or dipoles passing through the nanopore.

What is claimed is: 
     
       1. A method for electrically differentiating bases, the method comprising:
 providing a reservoir structure separated into two parts by a membrane, wherein a nanopore is formed through the membrane, wherein the membrane comprises a graphene layer and insulating layers, wherein the graphene layer is coupled to first and second metal pads to form a graphene transistor, wherein the first metal pad forms a step on one of the insulating layers such that a bottom surface of the first metal pad is directly on top of the graphene layer and the bottom surface is directly on top of the one of the insulating layers, while another one of the insulating layers is directly on top of the first metal pad, wherein the step of the first metal pad is external to the reservoir structure; and 
 using transistor current flowing through the graphene transistor to differentiate bases, the transistor current being modulated by charges or dipoles passing through the nanopore. 
 
     
     
       2. The method of  claim 1 , wherein the nanopore connects the two parts of the reservoir structure. 
     
     
       3. The method of  claim 1 , wherein the first and second metal pads include titanium. 
     
     
       4. The method of  claim 1 , wherein the first and second metal pads include palladium. 
     
     
       5. The method of  claim 1 , wherein the first and second metal pads include gold. 
     
     
       6. The method of  claim 1 , where the insulating layers include oxide. 
     
     
       7. The method of  claim 1 , where the insulating layers include nitride. 
     
     
       8. The method of  claim 1 , wherein the charges or dipoles correspond to a nucleobase of a nucleic acid molecule. 
     
     
       9. The method of  claim 8 , wherein when the nucleobase is in the nanopore, the transistor current modulates based on the charges or dipoles of the nucleobase to form a transistor current pulse. 
     
     
       10. The method of  claim 9 , further comprising determining the nucleobase based on at least one of a magnitude, a time duration, and a shape of the transistor current pulse when the nucleobase is in the nanopore. 
     
     
       11. The method of  claim 1 , wherein the charges or dipoles correspond to a biomolecule. 
     
     
       12. The method of  claim 11 , wherein when the biomolecule is in the nanopore, the transistor current modulates based on the charges or dipoles of the biomolecule to form a transistor current pulse. 
     
     
       13. The method of  claim 12 , further comprising determining the biomolecule based on at least one of a magnitude, a time duration, and a shape of the transistor current pulse when the biomolecule is in the nanopore. 
     
     
       14. The method of  claim 12 , wherein when a voltage is applied across the nanopore, an ionic current is changed based on a size of the biomolecule to form an ionic current pulse. 
     
     
       15. The method of  claim 14 , wherein the biomolecule is determined based on a magnitude and a time duration of the ionic current pulse when the biomolecule is in the nanopore. 
     
     
       16. The method of  claim 1 , wherein the reservoir structure includes ionic buffer. 
     
     
       17. The method of  claim 1 , wherein the nanopore is configured to pass a protein. 
     
     
       18. The method of  claim 1 , wherein the nanopore is configured to pass DNA. 
     
     
       19. The method of  claim 1 , wherein the nanopore is configured to pass RNA. 
     
     
       20. The method of  claim 1 , wherein the reservoir structure comprises a top part and a bottom part.