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Microgrid Electrode for Si Microwire Solar Cells with a Fill Factor of Over 80%
Author(s) -
Um HanDon,
Hwang Inchan,
Kim Namwoo,
Yu Young J.,
Wober Munib,
Kim KaHyun,
Seo Kwanyong
Publication year - 2015
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.201500347
Subject(s) - materials science , common emitter , electrode , optoelectronics , energy conversion efficiency , microgrid , open circuit voltage , electroplating , photovoltaic system , short circuit , current density , voltage , nanotechnology , electrical engineering , layer (electronics) , chemistry , physics , quantum mechanics , engineering
Here, a novel microgrid top electrode for highly efficient radial‐junction Si microwire solar cells is demonstrated. The microgrid electrode minimizes optical and electrical losses, thus ensuring proper function of the shallow (sheet resistance of ≈100 Ω sq −1 ) junction emitter. This leads to effective collection of the photocarriers from the shallow junction emitter through the top electrode without severe Auger/surface recombination, improving the overall power conversion efficiency of the Si microwire solar cell. With an optimized microgrid structure, 1 cm 2 microwire solar cells show a conversion efficiency of up to 16.5%, with an open‐circuit voltage of 565.2 mV and a short‐circuit current density of 35.9 mA·cm −2 ; this conversion efficiency is 72% higher than that of solar cells with an edge electrode (9.6%). Further, an ≈1 μm thick Ni electrode that is formed by electroplating considerably reduces the metal and contact resistances, which reproducibly yields a fill factor of over 80% (max 81.2%). Thus, the use of a novel microgrid to construct an ideal metal/emitter interface presents a unique opportunity to develop highly efficient microwire solar cells.