Piezoresistive boron doped diamond nanowire
A UNCD nanowire comprises a first end electrically coupled to a first contact pad which is disposed on a substrate. A second end is electrically coupled to a second contact pad also disposed on the substrate. The UNCD nanowire is doped with a dopant and disposed over the substrate. The UNCD nanowire is movable between a first configuration in which no force is exerted on the UNCD nanowire and a second configuration in which the UNCD nanowire bends about the first end and the second end in response to a force. The UNCD nanowire has a first resistance in the first configuration and a second resistance in the second configuration which is different from the first resistance. The UNCD nanowire is structured to have a gauge factor of at least about 70, for example, in the range of about 70 to about 1,800.
1. A method for preparing piezoresistive boron doped ultrananocrystalline diamond nanowires, comprising:
depositing a metal layer on a boron doped ultrananocrystalline diamond film, the boron doped ultrananocrystalline film disposed on a sacrificial layer, the sacrificial layer disposed on a substrate;
patterning the metal layer to form contact pads disposed on the boron doped ultrananocrystalline diamond film;
depositing a first masking layer on the boron doped ultrananocrystalline diamond film;
depositing a second masking layer over the first masking layer;
patterning the first masking layer and the second masking layer to define an etch mask;
etching the boron doped ultrananocrystalline diamond film to form boron doped ultrananocrystalline diamond nanowires; and
wherein the boron doped ultrananocrystalline diamond nanowires have a gauge factor of at least about 70.
2. The method of claim 1 , wherein the second masking layer is patterned using one of laser etching and electron beam lithography.
3. The method of claim 1 , wherein the UNCD film is deposited over the sacrificial layer using hot filament chemical vapor deposition.
4. The method of claim 1 , wherein the UNCD film is deposited over the sacrificial layer using microwave plasma deposition process.
5. The method of claim 1 , wherein the UNCD film has a first thickness of about 20 nm to about 200 nm.
6. The method of claim 1 , comprising depositing a UNCD film on the sacrificial layer and forming the boron doped ultrananocrystalline film disposed on a sacrificial layer.
7. The method of claim 6 , wherein the boron is doped by exposing boron gas during UCND deposition on the sacrificial layer.
8. The method of claim 1 , wherein the boron is doped by ex situ implantation into UNCD layer deposited on the sacrificial layer.
9. The method of claim 1 , wherein boron concentration in the B-UNCD film is in the range of about 1×1021 atoms per cm3 to about 9×1021 atoms per cm3.
10. The method of claim 9 , wherein the boron concentration in the B-UNCD films is about 4.8×1021 atoms per cm3.
11. The method of claim 1 , wherein the metal layer comprises at least one element selected from the group consisting of Cr, Ti, Pt, Au, or Cu.
12. The method of claim 11 , wherein the metal layer comprises a plurality of elements selected from the group consisting of Cr, Ti, Pt, Au, or Cu.
13. The method of claim 12 , wherein the metal layer comprises a Ti layer and a Pt layer, the Ti layer having a thickness of about 10 nm and the Pt layer having a thickness of about 100 nm.
14. The method of claim 1 , further comprising etching the sacrificial layer below the boron doped ultrananocrystalline diamond nanowires to release the boron doped ultrananocrystalline diamond nanowires.
15. The method of claim 14 , further comprising forming a wire having a width of about 20 nm to about 200 nm.
16. The method of claim 15 , wherein forming the wire comprises forming the wire with a length of about 0.5 micron to about 25 micron.
17. The method of claim 15 , wherein forming the wire comprises forming a wire having a gauge factor of about 70 to about 1,800.