Methods of fabricating nanostructures and nanowires and devices fabricated therefrom
View Patent ↗One-dimensional nanostructures having uniform diameters of less than approximately 200 nm. These inventive nanostructures, which we refer to as “nanowires”, include single-crystalline homostructures as well as heterostructures of at least two single-crystalline materials having different chemical compositions. Because single-crystalline materials are used to form the heterostructure, the resultant heterostructure will be single-crystalline as well. The nanowire heterostructures are generally based on a semiconducting wire wherein the doping and composition are controlled in either the longitudinal or radial directions, or in both directions, to yield a wire that comprises different materials. Examples of resulting nanowire heterostructures include a longitudinal heterostructure nanowire (LOHN) and a coaxial heterostructure nanowire (COHN).
1. A nanowire, comprising:
a core of a first material at least partially surrounded by a sheath of a compositionally different non-amorphous material;
wherein said nanowire is configured to be selected from a population of nanowires, said population of nanowires having a substantially uniform inter-wire diameter of less than 50% RMS.
2. A nanowire as recited in claim 1 , wherein each of said core and said sheath comprises a semiconductor material.
3. A nanowire as recited in claim 1 , wherein at least one of said core and said sheath comprises a doped semiconductor material.
4. A nanowire as recited in claim 1 , wherein at least one of said core and said sheath comprises a substantially crystalline material.
5. A nanowire as recited in claim 1 , wherein at least one of said core and said sheath has a diameter of less than approximately 200 nm.
6. A nanowire as recited in claim 5 , wherein said at least one of said core and said sheath has a diameter that does not vary by more than about 10% over the length of said core or sheath.
7. A nanowire as recited in claim 5 , wherein said at least one said core and said sheath has a diameter ranging from about 5 nm to about 50 nm.
8. A nanowire as recited in claim 1 , further comprising an electrode coupled to at least one of said core and said sheath.
9. A nanowire as recited in claim 1 , wherein said core comprises Si and said sheath comprises Si/Ge.
10. A nanowire as recited in claim 1 , wherein said nanowire transitions from said core to said sheath over a distance ranging from about 1 atomic layer to about 20 nm.
11. A nanowire as recited in claim 1 , wherein at least one of said core and said sheath comprises a substantially monocrystalline material.
12. A nanowire as recited in claim 1 , wherein said sheath comprises a substantially crystalline material.
13. A nanowire as recited in claim 12 , wherein said substantially crystalline material is substantially monocrystalline.
14. A nanowire as recited in claim 1 , wherein the nanowire is configured to be selected from a population of nanowires, said population of nanowires having a substantially uniform diameter of less than about 20% rms.
15. A nanowire as recited in claim 1 , wherein the nanowire is configured to be selected from a population of nanowires, said population of nanowires having a substantially uniform diameter of less than about 10% rms.
16. A nanowire as recited as in claim 1 , comprising two or more sheath layers surrounding said core.
17. A nanowire as recited in claim 1 , wherein said sheath comprises a semiconductor or a polymer material.
18. A nanowire, comprising:
a core of a first material at least partially surrounded by a sheath of a compositionally different non-amorphous material;
wherein said nanowire is configured to be selected from a population of nanowires, said population of nanowires having a substantially uniform diameter of less than 50% RMS; and
wherein said core comprises at least first and second segments of compositionally different materials.
19. A nanowire, comprising:
a core of a first material at least partially surrounded by a sheath of a compositionally different non-amorphous material;
wherein said nanowire is configured to be selected from a population of nanowires, said population of nanowires having a substantially uniform diameter of less than 50% RMS; and
wherein said sheath comprises at least first and second segments of compositionally different materials.
20. A nanowire, comprising:
a core of a first material at least partially surrounded by a sheath of a compositionally different non-amorphous material;
wherein said nanowire is configured to be selected from a population of nanowires, said population of nanowires having a substantially uniform diameter of less than 50% RMS; and
wherein said core comprises a single-segment core which is only partially surrounded by said sheath.
21. A population of nanowires, comprising:
an array of individual nanowires each having a core of a first material at least partially surrounded by a sheath of a compositionally different non-amorphous material;
wherein said population of nanowires has a substantially uniform inter-wire diameter of less than 50% RMS.
22. A population of nanowires as recited in claim 21 , wherein said population of nanowires has a substantially uniform diameter of less than about 20% rms.
23. A population of nanowires as recited in claim 21 , wherein said population of nanowires has a substantially uniform diameter of less than about 10% rms.