Efficient Light Trapping in Inverted Nanopyramid Thin Crystalline Silicon Membranes for Solar Cell Applications
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Author(s)
Mavrokefalos, Anastassios
Han, Sang Eon
Yerci, Selcuk
Chen, Gang
Branham, Matthew Sanders
Date Issued
May 2012
Journal
Nano Letters
Publisher
American Chemical Society (ACS)
Citation
Mavrokefalos, Anastassios, Sang Eon Han, Selcuk Yerci, Matthew S. Branham, and Gang Chen. “Efficient Light Trapping in Inverted Nanopyramid Thin Crystalline Silicon Membranes for Solar Cell Applications.” Nano Lett. 12, no. 6 (June 13, 2012): 2792–2796.
Version
Author's final manuscript
Abstract
Thin-film crystalline silicon (c-Si) solar cells with light-trapping structures can enhance light absorption within the semiconductor absorber layer and reduce material usage. Here we demonstrate that an inverted nanopyramid light-trapping scheme for c-Si thin films, fabricated at wafer scale via a low-cost wet etching process, significantly enhances absorption within the c-Si layer. A broadband enhancement in absorptance that approaches the Yablonovitch limit (Yablonovitch, E. J. Opt. Soc. Am.1987, 72, 899–907 ) is achieved with minimal angle dependence. We also show that c-Si films less than 10 μm in thickness can achieve absorptance values comparable to that of planar c-Si wafers thicker than 300 μm, amounting to an over 30-fold reduction in material usage. Furthermore the surface area increases by a factor of only 1.7, which limits surface recombination losses in comparison with other nanostructured light-trapping schemes. These structures will not only significantly curtail both the material and processing cost of solar cells but also allow the high efficiency required to enable viable c-Si thin-film solar cells in the future.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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DOI of Published Version
https://doi.org/10.1021/nl2045777
