Fabrication of aligned nanowire lattices
View Patent ↗Methodologies associated with fabricating aligned nanowire lattices are described. One exemplary method embodiment includes providing a twist wafer bonded thin single crystal semiconductor film and a bulk single crystal substrate of the same material. Periodic non-uniform elastic strains present on the surface of the film control the positions where nanocrystals will form on the film. The strains may be removed via annealing and alloying after the formation of nanocrystal arrays.
1. A method for fabricating aligned semiconductor nanowire lattices, comprising:
twist wafer bonding a thin single crystal semiconductor film and a bulk single crystal substrate of the same material as the film, the twist wafer bonding being configured to create a plurality of periodic non-uniform elastic fields on the surface of the film;
depositing on the film a seed alloy material that will nucleate a plurality of nanocrystals in a periodic array pattern on the film;
annealing the film, the substrate, and the nanocrystals at a temperature exceeding the seed alloy-substrate eutectic temperature until the nanocrystals alloy and contact the substrate through the film; and
epitaxially growing a plurality of aligned nanowires of the substrate material where the nanowires form aligned semiconductor nanowire lattices.
2. The method of claim 1 , the film being one of, Si, and a III-IV compound semiconductor material.
3. The method of claim 1 , the film being (111) oriented Si, the film being about fifty angstroms to about one hundred angstroms thick.
4. The method of claim 3 , the twist wafer bonding being performed with an angular misalignment between <011> directions of the film and the substrate.
5. The method of claim 4 , the angular misalignment being 0.5 degrees.
6. The method of claim 3 , the twist wafer bonding being configured to create a plurality of periodic dislocation arrays at an interface between the film and the substrate.
7. The method of claim 1 , the depositing being performed by chemical vapor deposition (CVD).
8. The method of claim 1 , the seed alloy material being one of gold (Au) and titanium (Ti).
9. The method of claim 1 , the nanocrystals being controlled to nucleate at points determined by the periodic non-uniform elastic fields.
10. The method of claim 6 , the nanocrystals being controlled to nucleate at points determined by the periodic non-uniform elastic fields.
11. A method for fabricating aligned semiconductor nanowire lattices, comprising:
twist wafer bonding a thin single crystal semiconductor film and a bulk single crystal substrate of the same material as the film;
depositing on the film a seed alloy material that will nucleate a plurality of nanocrystals in a periodic array pattern on the film;
annealing the film, the substrate, and the nanocrystals at a temperature exceeding the seed alloy-substrate eutectic temperature until the nanocrystals alloy and contact the substrate through the film; and
epitaxially growing a plurality of aligned nanowires of the substrate material where the nanowires form aligned semiconductor nanowire lattices;
where epitaxially growing a plurality of aligned nanowires includes introducing, under VLS (vapor-liquid-solid) conditions, a gas including the substrate material.
12. A method for fabricating aligned semiconductor nanowire lattices, comprising:
twist wafer bonding a thin single crystal semiconductor film and a bulk single crystal substrate of the same material as the film, the film being (111) oriented Si, the film being about fifty angstroms to one hundred angstroms thick, the twist wafer bonding being performed with an angular misalignment between <011> directions of the film and the substrate;
depositing on the film by chemical vapor deposition (CVD) a seed alloy material that will nucleate a plurality of nanocrystals in a periodic array pattern on the film, the seed alloy material being one of gold (Au) and titanium (Ti);
annealing one or more of, the nanocrystals, the film, and the substrate at a temperature exceeding the seed alloy substrate eutectic temperature until the nanocrystals alloy under the film and contact the substrate; and
epitaxially growing a plurality of aligned nanowires of the substrate material where the nanowires form aligned semiconductor nanowire lattices, where epitaxially growing includes introducing, under VLS conditions, a gas including the substrate material.
13. A method, comprising:
depositing on a thin single crystal semiconductor film that is twist wafer bonded to a bulk single crystal substrate of the same material as the film a seed alloy material that will nucleate a plurality of nanocrystals in a periodic array pattern on the film, the twist wafer bonding being configured to create a plurality of periodic non-uniform elastic fields on the surface of the film; and
annealing the film, the substrate, and the nanocrystals at a temperature exceeding the seed alloy-substrate eutectic temperature until the nanocrystals alloy and contact the substrate.
14. The method of claim 13 , comprising:
epitaxially growing a plurality of aligned nanowires of the substrate material where the nanowires form aligned semiconductor nanowire lattices.