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" A Cost-Effective Liquid Phase Epitaxy Process for High-Efficiency AlGaAs/GaAs Solar Cells "
Camron David Noorzad
Woodall, Jerry M.
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Latin Dissertation
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| Language of Document
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English
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| Record Number
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804893
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| Doc. No
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TL49729
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| Call number
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1992350762; 10608572
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| Main Entry
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Moaz, Marwa Tarek
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| Title & Author
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A Cost-Effective Liquid Phase Epitaxy Process for High-Efficiency AlGaAs/GaAs Solar Cells\ Camron David NoorzadWoodall, Jerry M.
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| College
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University of California, Davis
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| Date
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2017
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| Degree
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M.S.
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| field of study
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Electrical and Computer Engineering
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| student score
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2017
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| Page No
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48
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| Note
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Committee members: Islam, Saif M.; Seker, Erkin
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| Note
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Place of publication: United States, Ann Arbor; ISBN=978-0-355-45114-6
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| Abstract
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We report on an AlGaAs/GaAs solar cell with a significantly increased high-energy response that was produced via a modified liquid phase epitaxy (LPE) technique. This technique uses a one-step process in which the solid-liquid equilibrium Al-Ga-As:Zn melt in contact with an <i>n</i>-type vendor GaAs substrate simultaneously getters impurities in the substrate that shorten minority carrier lifetimes, diffuses Zn into the substrate to create a <i> p-n</i> junction, and forms a thin <i>p</i>-AlGaAs window layer that enables more high-energy light to be efficiently absorbed. Unlike conventional LPE, this process is performed isothermally. In our “double Al” method, the ratio of Al in the melt (“Al melt ratio”) that was used in our process was two times more than what was previously reported in the record-efficiency 1977 IBM solar cell. Photoluminescence (PL) results showed our double Al sample yielded a response to 405 nm (“purple”) light which was more than twice as intense as the response from our replicated IBM cell. The original 1977 cell had a low-intensity spectral response to photon wavelengths under 443 nm [1]. Secondary ion mass spectrometry (SIMS) results confirmed the increased blue light response was due to a large reduction in AlGaAs window layer thickness. These results proved increasing the Al melt ratio broadens the spectrum of light that can be transmitted through the window layer into the GaAs active region for absorption, increasing the overall solar cell efficiency. The measured open-circuit voltage and fill factor of our replicated IBM solar cell was about 0.89 V and 72%, respectively. By enhancing the 1977 IBM process, our double Al method can pave the way for large-scale manufacturing of low-cost, high-efficiency solar cells.
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| Subject
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Electrical engineering
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| Descriptor
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Applied sciences;Algaas/gaas;Liquid phase epitaxy;Physical electronics;Semiconductor device physics;Solar cells
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| Added Entry
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Woodall, Jerry M.
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| Added Entry
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Electrical and Computer EngineeringUniversity of California, Davis
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