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DOE OSTI · 3378275

15.3% AM1.5G Efficiency GaAs Solar Cells Fabricated via an Epitaxy-Free Process

Jahelka, Phillip R. [California Institute of Technology (CalTech), Pasadena, CA (United States)] (ORCID:0000000214607933)·Ptak, Aaron J. [National Laboratory of the Rockies (NLR), Golden, CO (United States)] (ORCID:0000000309978964)·Simon, John [National Laboratory of the Rockies (NLR), Golden, CO (United States)] (ORCID:0000000329873641)·Schulte, Kevin L. [National Laboratory of the Rockies (NLR), Golden, CO (United States)] (ORCID:0000000342736254)·Kiessling, Frank M. [Leibniz Inst. for Crystal Growth (IKZ), Berlin (Germany)] (ORCID:0000000176652214)·Frank-Rotsch, Christiane [Leibniz Inst. for Crystal Growth (IKZ), Berlin (Germany)] (ORCID:0000000185901403)·Torres-Londono, Susana [California Institute of Technology (CalTech), Pasadena, CA (United States)] (ORCID:0009000677975027)·Atwater, Harry A. [California Institute of Technology (CalTech), Pasadena, CA (United States)] (ORCID:0000000194350201)
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Abstract

Here, we report simple and potentially low-cost techniques for creating high-quality n-type gallium arsenide (GaAs) and GaAs p/n junctions and fabricate GaAs p/n junction solar cells. Detailed-balance modeling suggests that 20% AM1.5G efficiency p/n homojunction devices may be possible if the surface doping concentration can be limited to values less than ∼ 5 × 10 19 cm −3 . Our process exploits an open-tube, vapor-phase, deposition-free, zinc diffusion technique for forming p-type layers in melt-grown n-GaAs substrates that results in sheet resistances less than 1 kΩ/$\square$. In addition, we have improved the minority carrier diffusion lengths of melt-grown GaAs from less than one micron to over five microns using an open-tube, vacuum-free, annealing process which reduces the density of EL2 midgap defects. Finally, we have combined these advances to fabricate epitaxy-free, GaAs solar cells with a validated AM1.5G efficiency of 15.3%.

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14 SOLAR ENERGYgallium arsenide (GaAs)photovoltaic cellssemiconductor device doping

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Jahelka, Phillip R. [California Institute of Technology (CalTech), Pasadena, CA (United States)] (ORCID:0000000214607933), Ptak, Aaron J. [National Laboratory of the Rockies (NLR), Golden, CO (United States)] (ORCID:0000000309978964), Simon, John [National Laboratory of the Rockies (NLR), Golden, CO (United States)] (ORCID:0000000329873641), Schulte, Kevin L. [National Laboratory of the Rockies (NLR), Golden, CO (United States)] (ORCID:0000000342736254), Kiessling, Frank M. [Leibniz Inst. for Crystal Growth (IKZ), Berlin (Germany)] (ORCID:0000000176652214), Frank-Rotsch, Christiane [Leibniz Inst. for Crystal Growth (IKZ), Berlin (Germany)] (ORCID:0000000185901403), Torres-Londono, Susana [California Institute of Technology (CalTech), Pasadena, CA (United States)] (ORCID:0009000677975027), Atwater, Harry A. [California Institute of Technology (CalTech), Pasadena, CA (United States)] (ORCID:0000000194350201). 2026-09-01. 15.3% AM1.5G Efficiency GaAs Solar Cells Fabricated via an Epitaxy-Free Process. https://doi.org/10.1109/jphotov.2026.3702679

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