title: Light trapping in ultrathin plasmonic solar cells.
abstract: We report on the design, fabrication, and measurement of ultrathin film a-Si:H solar cells with nanostructured plasmonic back contacts, which demonstrate enhanced short circuit current densities compared to cells having flat or randomly textured back contacts. The primary photocurrent enhancement occurs in the spectral range from 550 nm to 800 nm. We use angle-resolved photocurrent spectroscopy to confirm that the enhanced absorption is due to coupling to guided modes supported by the cell. Full-field electromagnetic simulation of the absorption in the active a-Si:H layer agrees well with the experimental results. Furthermore, the nanopatterns were fabricated via an inexpensive, scalable, and precise nanopatterning method. These results should guide design of optimized, non-random nanostructured back reflectors for thin film solar cells.
authors.affiliation: Center for Nanophotonics, FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands. vivianf@caltech.edu
authors.forename: Vivian E
authors.initials: VE
authors.lastname: Ferry
authors.forename: Marc A
authors.initials: MA
authors.lastname: Verschuuren
authors.forename: Hongbo B T
authors.initials: HB
authors.lastname: Li
authors.forename: Ewold
authors.initials: E
authors.lastname: Verhagen
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Walters
authors.forename: Ruud E I
authors.initials: RE
authors.lastname: Schropp
authors.forename: Harry A
authors.initials: HA
authors.lastname: Atwater
authors.forename: Albert
authors.initials: A
authors.lastname: Polman