Mechanisms of Enhanced Optical Absorption for Ultrathin Silicon Solar Microcells with an Integrated Nanostructured Backside Reflector

    Authors

    C. J. Corcoran; S. M. Kang; L. F. Li; X. Y. Guo; D. Chanda;R. G. Nuzzo

    Comments

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    Abbreviated Journal Title

    ACS Appl. Mater. Interfaces

    Keywords

    light trapping; photovoltaics; optical nanostructures; PHOTOVOLTAIC APPLICATIONS; CRYSTALLINE SILICON; PLASMONIC MATERIALS; CELLS; DESIGN; ADHESION; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary

    Abstract

    This paper investigates mechanisms of enhanced light absorption exhibited by ultrathin Si solar microcells integrated with a periodically nanostructured, semitransparent metallic reflector. This backside reflector comprises periodic nanoscale relief features formed by soft-imprint lithography with a thin (similar to 35 nm) coating of Au. The work shows that microcells placed in direct contact above the nanostructured reflector's surface creates Fabry-Perot cavities, which traps impinging light inside the Si slab via the excitation of cavity modes. Experimental measurements show that the short-circuit current and efficiency values for devices incorporating this thin, semitransparent backside reflector outperform similar Si microcells integrated with a planar thick (similar to 300 nm) opaque mirror by similar to 10-15% because of enhanced absorption. Computational modeling that is supported by experimental measurements reveal that the dominant methods of enhancement stem from a complex interplay between backside diffraction/scattering and Fabry-Perot resonances. These same data demonstrate that plasmonic interactions contribute minimally to the optical enhancements seen.

    Journal Title

    Acs Applied Materials & Interfaces

    Volume

    5

    Issue/Number

    10

    Publication Date

    1-1-2013

    Document Type

    Article

    Language

    English

    First Page

    4239

    Last Page

    4246

    WOS Identifier

    WOS:000319551200037

    ISSN

    1944-8244

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