Gallium arsenide phosphide top solar cell
First Claim
1. In a tandem solar cell having a silicon solar cell for a low energy gap bottom cell and a high energy gap top cell, the improvement being a gallium arsenide phosphide top solar cell comprising:
- a. a transparent gallium phosphide substrate;
b. a first active semiconductor layer of GaAs1-y Py and of a first conductivity type overlying said substrate;
c. a second active semiconductor layer of GaAs1-x Px and of a second conductivity type opposite said first conductivity type overlying and forming a photovoltaic junction therewith;
d. a transparent first electrical contact in ohmic contact with said substrate; and
e. a transparent second electrical contact in ohmic contact with said second active semiconductor layer.
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Accused Products
Abstract
An improved tandem solar cell includes a gallium arsenide phosphide top solar cell and silicon bottom solar cell. The gallium arsenide phosphide solar cell is fabricated on a transparent gallium phosphide substrate and either placed in series with the silicon solar cell for a two terminal device or wired separately for a four terminal device. The top solar cell should have an energy gap between 1.77 and 2.09 eV for optimum energy conversion efficiency. A compositionally graded transition layer between the gallium phosphide substrate and the active semiconductor layers reduces dislocations in the active region. A gallium phosphide cap layer over the gallium arsenide phosphide solar cell reduces surface recombination losses.
58 Citations
13 Claims
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1. In a tandem solar cell having a silicon solar cell for a low energy gap bottom cell and a high energy gap top cell, the improvement being a gallium arsenide phosphide top solar cell comprising:
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a. a transparent gallium phosphide substrate; b. a first active semiconductor layer of GaAs1-y Py and of a first conductivity type overlying said substrate; c. a second active semiconductor layer of GaAs1-x Px and of a second conductivity type opposite said first conductivity type overlying and forming a photovoltaic junction therewith; d. a transparent first electrical contact in ohmic contact with said substrate; and e. a transparent second electrical contact in ohmic contact with said second active semiconductor layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification