PHOTOELECTRIC CONVERSION ELEMENT

• US 20100065121A1
• Filed: 09/15/2008
• Published: 03/18/2010
• Est. Priority Date: 09/15/2008
• Status: Active Grant

• Current Assignee: High Power Opto., Inc.
• Original Assignee: High Power Opto., Inc.
• Inventors: Sheu, Jinn-Kong, Chang, Chih-Sung, Yan, Liang-Jyi
• Granted Patent: US 7,956,282 B2
• Time in Patent Office: Days
• US Class Current: 136/261
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 31/035236 Superlattices; Multiple quantum well structures
• CPC Class Codes: H01L 31/125 Composite devices with photosensitive elements and electroluminescent elements within one single body

Abstract

A photoelectric conversion element comprises a solar-energy epitaxial layer, a bond layer and a LED epitaxial layer, which are stacked sequentially. The bond layer has a plurality of holes allowing light to pass. The solar-energy epitaxial layer receives light via the holes and generates electric energy, and an external secondary battery stores the electric energy. When environmental illumination disappears, the LED epitaxial layer is powered by the external secondary battery to emit light. When the photoelectric conversion element of the present invention applies to outdoor traffic signs, advertisement signboards and indicators, they can operate without external power supply.

Claims

1. A photoelectric conversion element comprising

a solar-energy epitaxial layer including an N-type semiconductor layer and a P-type semiconductor layer stacked together top down or bottom up;

a bond layer stacked on said solar-energy epitaxial layer and having a plurality of holes allowing light to pass; and

a LED (Light Emitting Diode) epitaxial layer stacked on said bond layer and including an electron supply layer, a hole supply layer and an active layer.

2. The photoelectric conversion element according to claim 1, wherein in said bond layer, an indium tin oxide layer, a silver layer, a titanium layer, a platinum layer, a gold layer, an indium layer, a gold layer and a titanium layer are stacked sequentially, and said indium tin oxide layer contacts said LED epitaxial layer, and said titanium layer contacts said solar-energy epitaxial layer.

3. The photoelectric conversion element according to claim 1, wherein said active layer has a MQW (Multiple Quantum Well) structure having a periodical structure containing AlInGaN (Aluminum Indium Gallium Nitride);

said electron supply layer is made of an N-type gallium nitride, and said hole supply layer is made of a P-type gallium nitride.

4. The photoelectric conversion element according to claim 1, wherein said N-type semiconductor layer and said P-type semiconductor layer of said solar-energy epitaxial layer are fabricated via preparing an N-type semiconductor substrate and doping a surface of said N-type semiconductor layer substrate to form a P-type semiconductor.

5. The photoelectric conversion element according to claim 1, wherein said plurality of holes are filled with a transparent material.

6. The photoelectric conversion element according to claim 2, wherein an ohmic contact layer is formed over said LED epitaxial layer, and a gold-beryllium alloy pad is formed in between said indium tin oxide layer and said LED epitaxial layer.

7. The photoelectric conversion element according to claim 6, wherein a protection layer is formed outside said LED epitaxial layer and outside said ohmic contact layer.

8. The photoelectric conversion element according to claim 7, wherein a portion of said LED epitaxial layer contacting said protection layer has a roughened surface.