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. A nanophotovoltaic device, comprising
a three-dimensional semiconductor structure comprising a p-doped portion and an n-doped portion, which form a p-n junction, said semiconductor structure having a size in each of said three dimensions in a range of about 50 nm to about 5000 nm,
a pair of metallic layers, each disposed on a portion of said semiconductor structure to form an ohmic contact therewith,
wherein exposure of said semiconductor structure to radiation having at least one selected wavelength causes creation of electron-hole pairs separated by a space charge generated by said p-n junction to provide a voltage across said metallic layers.
2. The nanophotovoltaic device of claim 1 , wherein said metallic layers have a thickness in a range of about 100 angstroms to about 1 micron.
3. The nanophotovoltaic device of claim 1 , wherein said semiconductor structure comprises any of Si and Ge.
4. The nanophotovoltaic device of claim 1 , wherein said semiconductor structure is selected from the group consisting of Group II-VI, Group III-V and Group IV semiconductors.
5. The nanophotovoltaic device of claim 1 , wherein said n-doped portion has a doping in a range of about 10 15 cm −3 to about 10 20 cm −3 .
6. The nanophotovoltaic device of claim 1 , wherein said p-doped portion has a doping in a range of about 10 15 cm −3 to about 10 20 cm −3 .
7. The nanophotovoltaic device of claim 1 , further comprising an insulating coating covering at least a portion of an external surface of said device.
8. The nanophotovoltaic device of claim 7 , wherein said insulating layer extends between said metallic layers.
9. The nanophotovoltaic device of claim 7 , wherein said insulating layer comprises an oxide layer.
10. The nanophotovoltaic device of claim 7 , wherein said insulating layer has a thickness in a range of about 5 nm to about 10 nm.
11. The nanophotovoltaic device of claim 1 , wherein said at least one selected wavelength lies in a range of about 400 nm to about 2000 nm.
12. The nanophotovoltaic device of claim 11 , wherein said at least one selected wavelength lies in a range of about 600 nm to about 1100 nm.
13. The nanophotovoltaic device of claim 1 , further comprising a ligand attached to a portion of said device.
14. A nanophotovoltaic device, comprising
a three-dimensional n-doped semiconductor portion having a size in each of said three dimensions in a range of about 50 nm to about 5000 nm, and
a three-dimensional p-doped semiconductor portion disposed adjacent to said n-doped portion to generate a p/n junction, said p-doped portion having a size in each of said three dimensions in a range of about 50 nm to about 5000 nm.
15. The nanophotovoltaic device of claim 14 , wherein said n-doped portion comprises any of silicon, germanium, or a Group III-V semiconducting composition.
16. The nanophotovoltaic device of claim 14 , wherein said p-doped portion comprises any of silicon, germanium, or a Group III-V semiconducting composition.
17. The nanophotovoltaic device of claim 14 , wherein said p-n junction provides a space charge region for facilitating separation of electron-hole pairs generated in response to irradiation of said p-n junction with radiation having one or more selected wavelength components.
18. The nanophotovoltaic device claim 17 , wherein said wavelength components lie in a range of about 400 nm to about 2000 nm.
19. The nanophotovoltaic device of claim 17 , wherein said wavelength components lie in a range of about 600 nm to about 1100 nm.
20. The nanophotovoltaic device of claim 17 , further comprising a pair of metallic layers disposed on selected portions of an external surface of said p-n junction to extracting a voltage generated by said separated electron-hole pairs.