title: Black silicon solar thin-film microcells integrating top nanocone structures for broadband and omnidirectional light-trapping.
abstract: Recently developed classes of monocrystalline silicon solar microcells (μ-cell) can be assembled into modules with characteristics (i.e., mechanically flexible forms, compact concentrator designs, and high-voltage outputs) that would be impossible to achieve using conventional, wafer-based approaches. In this paper, we describe a highly dense, uniform and non-periodic nanocone forest structure of black silicon (bSi) created on optically-thin (30 μm) μ-cells for broadband and omnidirectional light-trapping with a lithography-free and high-throughput plasma texturizing process. With optimized plasma etching conditions and a silicon nitride passivation layer, black silicon μ-cells, when embedded in a polymer waveguiding layer, display dramatic increases of as much as 65.7% in short circuit current, as compared to a bare silicon device. The conversion efficiency increases from 8.1% to 11.5% with a small drop in open circuit voltage and fill factor.
authors.affiliation: Micro and Nanotechnology Laboratory, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, IL 61801, USA.
authors.forename: Zhida
authors.initials: Z
authors.lastname: Xu
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yao
authors.forename: Eric P
authors.initials: EP
authors.lastname: Brueckner
authors.forename: Lanfang
authors.initials: L
authors.lastname: Li
authors.forename: Jing
authors.initials: J
authors.lastname: Jiang
authors.forename: Ralph G
authors.initials: RG
authors.lastname: Nuzzo
authors.forename: Gang Logan
authors.initials: GL
authors.lastname: Liu