Functional Integration Of Dilute Nitrides Into High Efficiency III-V Solar Cells
Tunnel junctions are improved by providing a rare earth-Group V interlayer such as erbium arsenide (ErAs) to yield a mid-gap state-assisted tunnel diode structure. Such tunnel junctions survive thermal energy conditions (time/temperature) in the range required for dilute nitride material integration into III-V multi-junction solar cells.
1 . A process for forming a III-V multi junction solar cell including forming a tunnel junction in the solar cell, the process comprising:
providing at least one layer containing a dilute nitride in the multi junction solar cell;
providing an n+ semiconductor layer associated with a tunnel junction;
providing a p+ semiconductor layer confronting the n+ semiconductor layer; and
providing a rare earth-Group V interlayer between the p+ layer and the n+ layer that forms a mid-gap-state-assisted tunnel diode; and
enhancing the dilute nitride layer to improve performance of the solar cell.
2 . The process according to claim 1 , the enhancing step comprising:
applying thermal energy to the multi junction solar cell sufficient to modify the voltage and current properties of the dilute nitride layer.
3 . The process according to claim 1 wherein the n+ layer is a III-V-based compound.
4 . The process according to claim 3 wherein the p+ layer is a III-V-based compound.
5 . The process according to claim 4 wherein the rare earth-Group V interlayer is an erbium-based compound.
6 . The process according to claim 1 wherein the rare earth-Group V interlayer is a compound of a lanthanide and a Group V element.
7 . The process according to claim 1 wherein the n+ layer is a dilute nitride.
8 . The process according to claim 1 wherein the n+ layer is selected from the group consisting of GaInNAs, GaInNAsSb, GaInNAsBi, and GaInNAsSbBi as a dilute nitride.
9 . The process according to claim 1 wherein the p+ layer is a dilute nitride.
10 . The process according to claim 1 wherein the p+ layer is selected from the group consisting of GaInNAs, GaInNAsSb, GaInNAsBi, and GaInNAsSbBi as a dilute nitride.
11 . The process according to claim 1 wherein
the n+ layer is selected from the group consisting of gallium arsenide, aluminum indium gallium phosphide, indium gallium phosphide, aluminum gallium arsenide, gallium indium arsenide, and aluminum gallium indium arsenide phosphide;
the p+ layer is selected from the group consisting of gallium arsenide, aluminum indium gallium phosphide, indium gallium phosphide, aluminum gallium arsenide, gallium indium arsenide, and aluminum gallium indium arsenide phosphide; and
the rare earth-Group V interlayer is selected from the group of erbium arsenide and erbium phosphide.
12 . A III-V compound-type multi junction solar cell having at least one sub-cell, the solar cell comprising:
a) a junction structure having:
an n+ semiconductor layer;
a p+ semiconductor layer; and
a rare earth-Group V interlayer between the p+ layer and the n+ layer that forms a mid-gap-state-assisted assisted tunnel diode;
b) at least one layer containing a dilute nitride,
c) wherein the solar cell has been subjected to thermal energy sufficient to modify the dilute nitride containing layer.
13 . The solar cell according to claim 12 wherein the annealing step is sufficient to modify voltage and current properties of the dilute nitride layer.
14 . The solar cell according to claim 12 wherein the n+ layer is a III-V-based compound.
15 . The solar cell according to claim 14 wherein the p+ layer is a III-V-based compound.
16 . The solar cell according to claim 15 wherein the rare earth-Group V interlayer is a compound of a lanthanide and a Group V element.
17 . The solar cell according to claim 15 wherein the rare earth-Group V interlayer
18 . The solar cell according to claim 12 wherein the n+ layer is a dilute nitride.
19 . The solar cell according to claim 12 wherein the n+ layer is selected from the group consisting of GaInNAs, GaInNAsSb, GaInNAsBi, and GaInNAsSbBi as a dilute nitride.
20 . The solar cell according to claim 12 wherein the p+ layer is a dilute nitride.
21 . The solar cell according to claim 12 wherein the p+ layer is selected from the group consisting of GaInNAs, GaInNAsSb, GaInNAsBi, and GaInNAsSbBi as a dilute nitride.
22 . The solar cell according to claim 12 wherein the n+ layer is selected from the group consisting of gallium arsenide, aluminum indium gallium phosphide, indium gallium phosphide, aluminum gallium arsenide, gallium indium arsenide, and aluminum gallium indium arsenide phosphide;
the p+ layer is selected from the group consisting of gallium arsenide, aluminum indium gallium phosphide, indium gallium phosphide, aluminum gallium arsenide, gallium indium arsenide, and aluminum gallium indium arsenide phosphide; and
the rare earth-Group V interlayer is selected from the group of erbium arsenide and erbium phosphide.