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EP-4735247-A1 - SCALABLE PRODUCTION OF GRAPHENE STRUCTURES

EP4735247A1EP 4735247 A1EP4735247 A1EP 4735247A1EP-4735247-A1

Abstract

The present disclosure relates to graphene structures, graphene-based devices and methods of fabrication thereof. The graphene structure detachably arranged and formed on a substrate comprises a graphene layer formed on the substrate. Further, the graphene structure comprises a first patterned structure extending above a first side of the graphene layer formed on the substrate. The graphene structure further comprises an attached cover layer over the first patterned structure and the graphene layer.

Inventors

  • KHAN, Munis
  • YURGENS, Avgust

Assignees

  • LayerLogic AB

Dates

Publication Date
20260506
Application Date
20240625

Claims (20)

  1. 1. A method (500) of fabricating a stacked graphene structure (1), the method comprising: forming a graphene layer (11) on a copper foil substrate (200); forming a first patterned structure (12) extending above a first side (11a) of the graphene layer formed on the copper foil substrate; forming, above the first patterned structure, a cover layer (13) by attaching the cover layer over the first patterned structure and the graphene layer; wherein the stacked graphene structure at least comprises the graphene layer, the first patterned structure and the attached cover layer.
  2. 2. The method (500) according to claim 1, wherein the method further comprises: forming the first patterned structure (12) by depositing the first patterned structure on top of the first side (11a) of the graphene layer.
  3. 3. The method (500) according to any one of claims 1 or 2, wherein the method further comprises: attaching the cover layer (13) in physical contact with a first side (12a) of the first patterned structure (12), by gluing the cover layer (13) on top of the first side (12a) of the first patterned structure and the first side (11a) of the graphene layer; and thereby providing a permanent attachment of the cover layer (13) on top of the first side (12a) of the first patterned structure and the first side of the graphene layer.
  4. 4. The method (500) according to claim 1, wherein the method further comprises: forming a second layer stack (14), made of Parylene N dielectric material, between the graphene layer formed on the copper foil substrate and the first patterned structure by depositing the second layer stack on top of the first side (11a) of the graphene layer formed on the substrate; and forming the first patterned structure on top of a first side (14a) of the deposited second layer stack; wherein the stacked graphene structure further comprises the second layer stack.
  5. 5. The method (500) according to claim 4, wherein the method further comprises: attaching the cover layer in physical contact with the first side (12a) of the first patterned structure (12) and the first side (14a) of the deposited second layer stack (14), by gluing the cover layer (13) on top of the first patterned structure (12) and the first side (14a) of the deposited second layer stack; and thereby providing a permanent attachment of the cover layer (13) on top of the first patterned structure (12) and the first side (14a) of the deposited second layer stack.
  6. 6. The method (500) according to any one of claims 1 - 5, wherein the first patterned structure (12) comprises a conductive material including metal or a conductive ink and the first patterned structure is adapted as a conductive electrode.
  7. 7. The method (500) according to any one of preceding claims, wherein the cover layer (13) comprises an insulating material including any one of plastic, thermoplastic, glass or sapphire, and wherein the cover layer is arranged to form a base on which the stacked graphene structure (1) will rest.
  8. 8. The method (500) according to claim 7, wherein the cover layer (13) comprises plastic formed of a dual-layer structure, the dual layer structure comprising a first sub-layer (13-1) made of ethylene-vinyl acetate, EVA, and a second sub-layer (13-2) made of polyethylene terephthalate, PET.
  9. 9. The method (500) according to any one of preceding claims, wherein the method further comprises: separating the stacked graphene structure (1) from the copper foil substrate (200) by means of detaching the stacked graphene structure such that a second side (lib) of the graphene layer opposite to the first side (11a) of the graphene layer is exposed.
  10. 10. The method (500) according to claim 9, wherein the method further comprises: detaching the stacked graphene structure from the copper foil substrate by means of any one of: an electrochemical delamination, a mechanical delamination, or an etching process.
  11. 11. The method (500) according to any one of claims 9 or 10, wherein the method further comprises: forming a third layer stack (16) by depositing the third layer stack on top of the exposed second side (lib) of the graphene layer which is separated from the copper foil substrate; and/or forming a second patterned structure (15) extending above the second side of the graphene layer.
  12. 12. A stacked graphene structure (1) detachably arranged and formed on a copper foil substrate (200), wherein the graphene structure comprises: a graphene layer (11) formed on the substrate; a first patterned structure (12) extending above a first side (11a) of the graphene layer formed on the substrate; and an attached cover layer (13) over the first patterned structure and the graphene layer.
  13. 13. The stacked graphene structure according to claim 12, wherein the graphene structure further comprises: a second layer stack (14), made of Parylene N dielectric material, arranged between the graphene layer and the first patterned structure, the second layer stack being deposited on top of the first side of the graphene layer; wherein the first patterned structure is arranged on top of a first side (14a) of the deposited second layer stack.
  14. 14. A graphene-based sensor device (110) or a graphene-field effect transistor device (110, 120, 130) comprising a stacked graphene structure fabricated by a method according to any one of the claims 1 - 11.
  15. 15. A graphene-field effect transistor device (110, 120, 130) formed by a method and comprising a stacked graphene-based structure (1) according to any one of claims 1 - 13, the transistor device comprising: a graphene layer (11) having a first side (11a) and a second side (lib) opposite the first side; a gate dielectric layer stack (14) made of Parylene N arranged at the first side (11a) of the graphene layer; a first patterned gate electrode (12) arranged at a first side (14a) of the gate dielectric layer stack (14); a cover layer (13) attached over the first patterned gate electrode and the first side of the gate dielectric layer stack, the attached cover layer configured to encompass the first patterned gate electrode and further to support the first patterned gate electrode, the gate dielectric layer stack, and the graphene layer; a second pattered electrode structure (15) comprising a first source electrode portion (15a) and a second drain electrode portion (15b) arranged at opposite ends (11c, lid) of the graphene layer; wherein the second side (lib) of the graphene layer is exposed.
  16. 16. The graphene-field effect transistor device according to claim 15, wherein the transistor device further comprises: a cover dielectric layer (16) arranged at the second side (lib) of the graphene layer, and configured to cover the exposed second side of the graphene layer.
  17. 17. A method (600) of fabricating a stacked graphene structure (1), the method comprising: forming a first patterned structure (12) extending above a first side (13a) of a cover layer (13) configured to support the first patterned structure (12), thereby forming a pre- patterned cover layer (131); wherein the first patterned structure (12) is made of a conductive material; attaching the pre-patterned cover layer (131) over a graphene layer (11) formed on a copper foil substrate (200), wherein the stacked graphene structure (1) at least comprises the graphene layer (11), and the attached pre-patterned cover layer (131).
  18. 18. The method (600) according to claim 17, wherein the method further comprises: attaching the pre-patterned cover layer (131), by gluing the pre-patterned cover layer (131) on top of a first side (11a) of the graphene layer; such that a first side (12a) of the patterned electrode structure (12), and a first surface (13a) of the cover layer (13) are arranged in physical contact with the first side (11a) of the graphene layer (11); thereby providing a permanent attachment of the pre-patterned cover layer (131) on top of the first side (11a) of the graphene layer (11).
  19. 19. The method (600) according to any one of claims 17 or 18, wherein the method further comprises: separating the stacked graphene structure (1) from the copper foil substrate (200) by means of detaching the stacked graphene structure such that a second side (lib) of the graphene layer (11) opposite to the first side (lib) of the graphene layer (11) is exposed.
  20. 20. The method (600) according to claim 19, wherein the method further comprises: patterning the graphene layer (11) in the detached stacked graphene structure (1) in order to form a patterned graphene layer (111), wherein the patterned graphene layer (111) is arranged to cover a first side (12a) of the first patterned structure (12) and wherein the second side (lib) of the patterned graphene layer (111) is exposed.

Description

TITLE Scalable production of graphene structures TECHNICAL FIELD The present disclosure relates to stacked graphene structures as well as methods of forming such a graphene structure. Particularly, embodiments and aspects of the present disclosure relate to graphene-based devices comprising the stacked graphene structure and applications thereof. BACKGROUND Graphene, since its discovery, has emerged as a highly promising two-dimensional (2D) material in the field of electronics and optoelectronics. Its flexibility, transparency, and excellent conductivity have paved the way for advancements in several scientific fields such as flexible electronics, sensing, and transistor devices to name a few. The exceptional mechanical properties of graphene have garnered substantial attention for use in stretchable electronic devices. Additionally, graphene possesses desirable properties such as high chemical stability, a wide optical absorption spectrum, excellent transparency, and electrical sensitivity to biochemicals, making it a promising material for displays, light harvesting devices, and biosensors. Chemical vapor deposition (CVD) of graphene on copper foils has been found to provide a scalable approach for obtaining high-quality single-layer graphene, which can then be used for further processing and intended applications. High-quality graphene refers to material free from contamination, wrinkles, cracks, or any other defects, characterized by its singlecrystalline nature. However, transferring graphene to a different substrate is often required for the subsequent applications. The widely used approach involves the deposition of a sacrificial polymer layer on the grown graphene layer, followed by the removal of the copper substrate and dissolution of the polymer layer. Unfortunately, this process is tedious and usually leads to contamination of the graphene surface by polymer residues. The contaminations lead to worsening of graphene's electrical properties, in particular, to lower carrier mobility of the transferred graphene compared to exfoliated graphene. Despite ongoing efforts, the mass production of high-quality graphene devices using scalable and cost-effective methods remains a challenge and there is a need in the field of graphene production as well graphenebased devices for development of versatile solutions, which address some of the above- mentioned drawbacks. SUMMARY It is accordingly an objective of the present invention to improve the current state of the art and to mitigate at least some of the above-mentioned problems. These and other objectives are achieved by providing a method of forming a stacked graphene structure, the formed stacked graphene structure and graphene-based devices fabricated by the proposed method as defined in the appended independent and dependent claims. The term exemplary is in the present context to be understood as serving as an instance, example or illustration. According to a first aspect of the present disclosure, there is provided a method of fabricating a stacked graphene structure. The method comprising forming a graphene layer on a substrate and forming a first patterned structure extending above a first side of the graphene layer formed on the substrate. The method further comprises forming, above the first patterned structure, a cover layer by attaching the cover layer over the first patterned structure and the graphene layer formed on the substrate; wherein the stacked graphene structure at least comprises the graphene layer, the first patterned structure and the attached cover layer. In various exemplary embodiments, the method may further comprise forming the first patterned structure by depositing the first patterned structure on top of the first side of the graphene layer formed on the substrate. Additionally or alternatively, the method may comprise forming the first patterned structure by depositing the first patterned structure at one or more edge portions of the graphene layer. According to several embodiments, the method may further comprise attaching the cover layer on top of a first side of the first patterned structure as well as on top of the first side of the graphene layer formed on the substrate. In more detail, the method may comprise attaching the cover layer in physical contact with the first side of the first patterned structure, by gluing the cover layer on top of the first side of the first patterned structure and the first side of the graphene layer. The method may further comprise providing a permanent attachment of the cover layer on top of the first side of the first patterned structure and the first side of the graphene layer. According to several embodiments, the method may further comprise forming a second layer stack between the graphene layer formed on the substrate and the first patterned structure by depositing the second layer stack on top of the first side of the graphene layer formed on the substrate. The method may furt