Selective processing of semiconductor nanowires by polarized visible radiation
View Patent ↗Methods, systems, and apparatuses for annealing semiconductor nanowires and for fabricating electrical devices are provided. Nanowires are deposited on a substrate. A plurality of electrodes is formed. The nanowires are in electrical contact with the plurality of electrodes. The nanowires are doped. A polarized laser beam is applied to the nanowires to anneal at least a portion of the nanowires. The nanowires may be aligned substantially parallel to an axis. The laser beam may be polarized in various ways to modify absorption of radiation of the applied laser beam by the nanowires. For example, the laser beam may be polarized in a direction substantially parallel to the axis or substantially perpendicular to the axis to enable different nanowire absorption profiles.
1. A method for fabricating an electrical device, comprising:
depositing a first at least one nanowire on a substrate;
forming first and second metal electrodes, the first at least one nanowire being in electrical contact with the first and second metal electrodes;
doping the first at least one nanowire; and
applying a polarized laser beam to a plurality of nanowires on the substrate that includes the first at least one nanowire and a second at least one nanowire, the polarized laser beam having a fluence level and a polarization that anneals the first at least one nanowire and ablates the second at least one nanowire on the substrate.
2. The method of claim 1 , wherein said depositing comprises:
aligning the first at least one nanowire to be substantially parallel to an axis.
3. The method of claim 1 , wherein said applying comprises:
polarizing the laser beam in a direction substantially parallel to the axis.
4. The method of claim 2 , wherein said applying comprises:
polarizing the laser beam in a direction substantially perpendicular to the axis.
5. The method of claim 4 , wherein said applying further comprises:
irradiating the first at least one nanowire and the second at least one nanowire with the polarized laser beam at a fluence level less than 100 mJ/cm 2 .
6. The method of claim 1 , further comprising:
selecting a fluence level of the polarized laser beam to anneal the first at least one nanowire without melting the first at least one nanowire.
7. The method of claim 1 , wherein said applying comprises:
pulsing the polarized laser beam.
8. The method of claim 1 , further comprising:
forming a third electrode in electrical contact with the first at least one nanowire.
9. The method of claim 1 , wherein said applying comprises:
forming the polarized laser beam to have a substantially flat top beam profile.
10. The method of claim 1 , wherein said applying comprises:
generating the polarized laser beam to have a visible light frequency.
11. An electrical device fabricated according to the method of claim 1 .
12. A method for annealing nanowires, comprising:
irradiating at least a portion of a first at least one nanowire and a second at least one nanowire with a polarized laser beam having a visible light frequency, a fluence level, and a polarization to simultaneously anneal the first at least one nanowire and ablate the second at least one nanowire.
13. The method of claim 12 , further comprising:
positioning the first at least one nanowire and the second at least one nanowire on a transparent substrate; and
wherein the polarized laser beam transmits through the transparent substrate during said irradiating without causing substantial damage to the transparent substrate.