Nanophotovoltaic devices

• US 7,514,725 B2
• Filed: 11/30/2004
• Issued: 04/07/2009
• Est. Priority Date: 11/30/2004
• Status: Expired due to Fees

• 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:
  US11/002,850
• Publication Number:
  US 20060113557A1
• Time in Patent Office: 1,589 Days
• Field of Search: 257/461, 257/103, 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. 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 SiO₂.

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.