Multiple bandgap solar cell on transparent substrate
AssigneeInternational Business Machines Corporation
InventorHarold J. Hovel
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Abstract
The disclosure provides a highly efficient e.g., up to 40% efficiency, solar cell for solar energy concentrator use. Two solar cell layers comprised of different semiconductor materials are grown upon a transparent, insulating substrate. A metal layer covering the bottom serves to reflect light back through the structure, and can serve as a wrap-around electrical contact to both materials. As an example, a structure of Si and GaAlAs is produced on a substrate from the group consisting of Al.sub.2 O.sub.3, Spinel, Quartz and BeO.
Claims10
A solar cell structure comprising:
- an optically transparent, electrically insulating substrate,
- at least one semiconductor material on a first upper surface of said substrate,
- at least one semiconductor material on a second lower surface of said substrate,
- the upper semiconductor material having larger energy bandgap than at least one of the lower semiconductor materials,
- first and second photoactive solar cell means in said upper and lower semiconductor materials respectively, at least one of said solar cell means having a Schottky barrier, and
- a reflective metal layer covering the bottom surface of the lower semiconductor materials,
- said reflective metal layer wrapping around the edge to connect the two solar cell devices in electrical series.
A solar energy converter comprising:
- a first light energy frequency responsive energy conversion region in epitaxial relationship with a first major surface of a transparent substrate member having said first and second major surfaces,
- a second light energy frequency responsive solar energy conversion region in epitaxial relationship with said second major surface of said substrate,
- means for providing concentrated light that passes through said first energy conversion region,
- said substrate and said second energy conversion region being in optical series, and
- a reflective metal member in contact with the exposed major surface of said second region,
- said reflective metal member forming a Schottky barrier to said exposed major surface of said second region,
- said reflective member being continuous around the periphery of said converter and providing electrical contact to both said first region and said second region.
A solar cell structure having a transparent insulating substrate with photoactive material thereon responsive to different wavelengths of light on opposite sides and having a reflective metal layer on one said photoactive material on the side away from the incident light forming a Schottky barrier with said photoactive material.
A solar cell structure having a transparent insulating substrate with respective solar cell devices thereon on each side of said substrate,
- the solar cell material of said solar cell on the light incident side having a larger energy bandgap than the solar cell material on the opposite side and said incident solar cell device being made with a transparent Schottky barrier, and
- the opposite solar cell device being covered with a reflective metal layer which wraps around the edge to make electrical contact to a portion of the incident solar cell device.
A solar cell structure comprising:
- an optically transparent substrate selected from the group consisting of Al.sub.2 O.sub.3, Spinel, Quartz, BeO, Glasses and Aluminas;
- a layer on one surface of said substrate taken from the group of GaAs, GaAlAs, GaP, amorphous Si, GaAsP, CdS, CdSe and CdTe forming one solar cell device having a first Schottky barrier and having a first energy gap;
- a layer on the opposite surface of said substrate selected from the group consisting of crystalline Si, Ge, GaSb, GaInAs, and InP forming a second solar cell device having a second Schottky barrier and having a second energy gap;
- and
- a metal layer wrapping around the edges to connect said solar cell devices in electrical series.
A solar cell structure comprising:
- an optically transparent, electrically insulating substrate,
- at least one semiconductor material on a first upper surface of said substrate,
- at least one semiconductor material on a second lower surface of said substrate,
- the upper semiconductor material having larger energy bandgap than at least one of the lower semiconductor materials,
- first and second photoactive solar cell means in said upper and lower semiconductor materials respectively, at least one said solar cell means having a Schottky barrier, and
- a reflective metal layer covering the bottom surface of the lower semiconductor materials.
A solar energy converter comprising:
- a first light energy frequency responsive energy conversion region in epitaxial relationship with a first major surface of a transparent substrate member having said first and second major surfaces,
- a second light energy frequency responsive solar energy conversion region in epitaxial relationship with said second major surface of said substrate,
- means for providing concentrated light that passes through said first energy conversion region,
- said substrate and said second energy conversion region being in optical series, and
- a reflective metal member in contact with the exposed major surface of said second region, said reflective metal member forming a Schottky barrier to said exposed major surface of said second region.
Dependencies are inferred from the claim text.