Nanophotovoltaic devices
View Patent ↗The present invention provides nanophotovoltaic devices having sizes in a range of about 50 nm to about 5 microns, and method of their fabrication. In some embodiments, the nanophotovoltaic device includes a semiconductor core, e.g., formed of silicon, sandwiched between two metallic layers, one of which forms a Schottky barrier junction with the semiconductor core and the other forms an ohmic contact therewith. In other embodiment, the nanophotovoltaic device includes a semiconductor core comprising a p-n junction that is sandwiched between two metallic layers forming ohmic contacts with the core.
1. An nanophotovoltaic device, comprising
a three-dimensional semi-conductor structure,
a metallic layer disposed over at least a portion of the semiconductor structure to form a junction therewith, said junction defining a space charge region,
wherein a combination of said semi-conductor structure and said metallic layer has a size in each of said three dimensions in a range of about 50 nm to about 5000 nm,
wherein exposure of said nanophotovoltaic device to radiation having a selected wavelength causes generation of electron-hole pairs that provide a voltage across the device.
2. The nanophotovoltaic device of claim 1 , wherein said space charge region supports an electric field that causes separation of said electron-hole pairs to facilitate generation of said voltage.
3. The nanophotovoltaic device of claim 1 , wherein said semiconductor structure comprises a biocompatible semiconductor material.
4. The nanophotovoltaic device of claim 1 , wherein said metallic layer comprises a biocompatible metallic material.
5. The nanophotovoltaic device of claim 1 , wherein said semiconductor comprises any of Si and Ge.
6. The nanophotovoltaic device of claim 1 , wherein said semiconductor is selected from the group consisting of Group II-VI, Group III-V and Group IV semiconductors.
7. The nanophotovoltaic device of claim 1 , wherein said metallic layer comprises a metal selected from the group consisting of gold, silver, platinum, titanium, palladium and alloys thereof.
8. The nanophotovoltaic device of claim 1 , wherein said semiconductor exhibits a direct bandgap and said radiation wavelength corresponds to said bandgap energy.
9. The nanophotovoltaic device of claim 1 , wherein said radiation wavelength is selected to be in range of about 400 nm to about 2000 nm.
10. The nanophotovoltaic device of claim 9 , wherein said radiation wavelength is selected to be in range of about 600 nm to about 1100 nm.
11. The nanophotovoltaic device of claim 1 , further comprising an insulating layer coating at least a portion of said semiconductor structure.
12. The nanophotovoltaic device of claim 11 , wherein said insulating layer has a thickness in a range of about 5 angstroms to about 500 angstroms.
13. The nanophotovoltaic device of claim 11 , wherein said insulating layer comprises an oxide layer.
14. The nanophotovoltaic device of claim 11 , wherein said semiconductor is silicon and said insulating layer comprises SiO 2 .
15. The nanophotovoltaic device of claim 1 , further comprising at least one ligand coupled to a surface of the nanophotovoltaic device.
16. The nanophotovoltaic device of claim 15 , wherein the ligand has an affinity for certain biological cells.
17. A nanophotovoltaic device, comprising
a semiconductor structure,
a metallic layer disposed over at least a portion of the semiconductor structure to form a junction therewith, said junction defining a space charge therein,
wherein said device has a substantially cylindrical shape with a height in a range of about 100 nm to about 1000 nm and a diameter in range of about 100 nm to about 1000 nm.