Nanophotovoltaic devices

• US 7,772,612 B2
• Filed: 02/19/2009
• Issued: 08/10/2010
• Est. Priority Date: 11/30/2004
• Status: Active Grant

• Current Assignee: Masimo Semiconductor Inc. (Masimo Corporation)
• Original Assignee: Spire Corporation
• Inventors: Moe, James G., Wojtczuk, Steven J., Little, Roger G.
• Primary Examiner(s): Le; Thao P.
• Application Number:
  US12/388,895
• Publication Number:
  US 20090165852A1
• Time in Patent Office: 537 Days
• Field of Search: 257/103, 257/461, 136/249
• US Class Current: 257/103
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01L 31/035281 Shape of the body
• CPC Class Codes: H01L 31/07 the potential barriers being only of the Schottky type
• CPC Class Codes: H01L 31/18 Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

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.

Claims

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 10¹⁵ cm⁻

3 to about 10²⁰ cm<sup>−

3</sup>.

6. The nanophotovoltaic device of claim 1, wherein said p-doped portion has a doping in a range of about 10¹⁵ cm⁻

3 to about 10²⁰ cm<sup>−

3</sup>.

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.