Thin film compositions and methods
Certain embodiments of the present invention include a versatile and scalable process, “patterned regrowth,” that allows for the spatially controlled synthesis of lateral junctions between electrically conductive graphene and insulating h-BN, as well as between intrinsic and substitutionally doped graphene. The resulting films form mechanically continuous sheets across these heterojunctions. These embodiments represent an element of developing atomically thin integrated circuitry and enable the fabrication of electrically isolated active and passive elements embedded in continuous, one atom thick sheets, which may be manipulated and stacked to form complex devices at the ultimate thickness limit.
1. A method of forming a mechanically continuous hybrid thin film, comprising:
growing a first film of a first material on a first substrate;
removing first material from selected regions of the first film; and
growing a second film of a second material in the selected regions of the first film such that the first film and second film form a mechanically continuous hybrid thin film having one or more lateral junctions between the first film and second film.
2. The method of claim 1 , wherein the first material is a first conductive material.
3. The method of claim 1 , wherein the second material is a second conductive material, an insulating material, or a semi-conducting material.
4. The method of claim 1 , wherein the first material is graphene.
5. The method of claim 4 , wherein the second material is a substitutionally doped graphene.
6. The method of claim 5 , wherein the substitutionally doped graphene is either N-doped or B-doped graphene.
7. The method of claim 3 , wherein the second material is hexagonal boron nitride.
8. The method of claim 3 , wherein the second material is selected from two dimensional metal dichalcogenides (TMDs).
9. The method of claim 8 , wherein the TMD is molybdenum disulfide or molybdenum diselenide.
10. The method of claim 1 , wherein growing the first film and/or growing the second film is performed under conditions that promote uniform lateral connectivity between the first film and second film.
11. The method of claim 10 , wherein the conditions include a highly reactive environment.
12. The method of claim 5 , wherein the one or more lateral junctions are electrically continuous.
13. The method of claim 12 , wherein resistance across the lateral junctions is less than 110% of resistance of a non-junction region of the first film.
14. The method of claim 7 , wherein regions of the continuous film comprising graphene exhibit conductivity and regions of the mechanically continuous thin film comprising boron nitride exhibit insulating characteristics.
15. The method of claim 1 , further comprising stacking a plurality of mechanically continuous hybrid thin films according to claim 1 on top of each other on a substantially planar second substrate.
16. The method of claim 15 , wherein the second substrate is a semiconductor.
17. The method of claim 1 , wherein first material is removed from selected regions of the first film using photolithography and reactive ion etching.
18. The method of claim 1 , wherein the mechanically continuous hybrid thin film is an atomically thin film.