title: High Performance Ultrathin GaAs Solar Cells Enabled with Heterogeneously Integrated Dielectric Periodic Nanostructures.
abstract: Due to their favorable materials properties including direct bandgap and high electron mobilities, epitaxially grown III-V compound semiconductors such as gallium arsenide (GaAs) provide unmatched performance over silicon in solar energy harvesting. Nonetheless, their large-scale deployment in terrestrial photovoltaics remains challenging mainly due to the high cost of growing device quality epitaxial materials. In this regard, reducing the thickness of constituent active materials under appropriate light management schemes is a conceptually viable option to lower the cost of GaAs solar cells. Here, we present a type of high efficiency, ultrathin GaAs solar cell that incorporates bifacial photon management enabled by techniques of transfer printing to maximize the absorption and photovoltaic performance without compromising the optimized electronic configuration of planar devices. Nanoimprint lithography and dry etching of titanium dioxide (TiO2) deposited directly on the window layer of GaAs solar cells formed hexagonal arrays of nanoscale posts that serve as lossless photonic nanostructures for antireflection, diffraction, and light trapping in conjunction with a co-integrated rear-surface reflector. Systematic studies on optical and electrical properties and photovoltaic performance in experiments, as well as numerical modeling, quantitatively describe the optimal design rules for ultrathin, nanostructured GaAs solar cells and their integrated modules.
authors.affiliation: Department of Chemical Engineering and Materials Science, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Sung-Min
authors.initials: SM
authors.lastname: Lee
authors.affiliation: Department of Chemical Engineering and Materials Science, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Anthony
authors.initials: A
authors.lastname: Kwong
authors.affiliation: Department of Electrical Engineering, Yale University , New Haven, Connecticut 06511, United States.
authors.forename: Daehwan
authors.initials: D
authors.lastname: Jung
authors.affiliation: Department of Electrical Engineering, Yale University , New Haven, Connecticut 06511, United States.
authors.forename: Joseph
authors.initials: J
authors.lastname: Faucher
authors.affiliation: Department of Electrical Engineering, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Roshni
authors.initials: R
authors.lastname: Biswas
authors.affiliation: Department of Chemical Engineering and Materials Science, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Lang
authors.initials: L
authors.lastname: Shen
authors.affiliation: Department of Chemical Engineering and Materials Science, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Dongseok
authors.initials: D
authors.lastname: Kang
authors.affiliation: Department of Electrical Engineering, Yale University , New Haven, Connecticut 06511, United States.
authors.forename: Minjoo Larry
authors.initials: ML
authors.lastname: Lee
authors.affiliation: Department of Chemical Engineering and Materials Science, University of Southern California , Los Angeles, California 90089, United States.|Department of Electrical Engineering, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Jongseung
authors.initials: J
authors.lastname: Yoon
keywords: III−V solar cells; nanophotonic light management; titanium dioxide; transfer printing; ultrathin gallium arsenide