title: Magnesium Fluoride Electron-Selective Contacts for Crystalline Silicon Solar Cells.
abstract: In this study, we present a novel application of thin magnesium fluoride films to form electron-selective contacts to n-type crystalline silicon (c-Si). This allows the demonstration of a 20.1%-efficient c-Si solar cell. The electron-selective contact is composed of deposited layers of amorphous silicon (∼6.5 nm), magnesium fluoride (∼1 nm), and aluminum (∼300 nm). X-ray photoelectron spectroscopy reveals a work function of 3.5 eV at the MgF2/Al interface, significantly lower than that of aluminum itself (∼4.2 eV), enabling an Ohmic contact between the aluminum electrode and n-type c-Si. The optimized contact structure exhibits a contact resistivity of ∼76 mΩ·cm(2), sufficiently low for a full-area contact to solar cells, together with a very low contact recombination current density of ∼10 fA/cm(2). We demonstrate that electrodes functionalized with thin magnesium fluoride films significantly improve the performance of silicon solar cells. The novel contacts can potentially be implemented also in organic optoelectronic devices, including photovoltaics, thin film transistors, or light emitting diodes.
authors.affiliation: Research School of Engineering, The Australian National University (ANU) , Canberra, Australian Capital Territory 0200, Australia.
authors.forename: Yimao
authors.initials: Y
authors.lastname: Wan
authors.affiliation: Research School of Engineering, The Australian National University (ANU) , Canberra, Australian Capital Territory 0200, Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: Samundsett
authors.affiliation: Research School of Engineering, The Australian National University (ANU) , Canberra, Australian Capital Territory 0200, Australia.|Department of Electrical Engineering and Computer Sciences, University of California , Berkeley, California 94720, United States.
authors.forename: James
authors.initials: J
authors.lastname: Bullock
authors.affiliation: Research School of Engineering, The Australian National University (ANU) , Canberra, Australian Capital Territory 0200, Australia.
authors.forename: Thomas
authors.initials: T
authors.lastname: Allen
authors.affiliation: Department of Electrical Engineering and Computer Sciences, University of California , Berkeley, California 94720, United States.
authors.forename: Mark
authors.initials: M
authors.lastname: Hettick
authors.affiliation: Research School of Engineering, The Australian National University (ANU) , Canberra, Australian Capital Territory 0200, Australia.
authors.forename: Di
authors.initials: D
authors.lastname: Yan
authors.affiliation: Research School of Engineering, The Australian National University (ANU) , Canberra, Australian Capital Territory 0200, Australia.
authors.forename: Peiting
authors.initials: P
authors.lastname: Zheng
authors.affiliation: Research School of Engineering, The Australian National University (ANU) , Canberra, Australian Capital Territory 0200, Australia.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Research School of Engineering, The Australian National University (ANU) , Canberra, Australian Capital Territory 0200, Australia.
authors.forename: Jie
authors.initials: J
authors.lastname: Cui
authors.affiliation: Research School of Engineering, The Australian National University (ANU) , Canberra, Australian Capital Territory 0200, Australia.
authors.forename: Josephine
authors.initials: J
authors.lastname: McKeon
authors.affiliation: Department of Electrical Engineering and Computer Sciences, University of California , Berkeley, California 94720, United States.
authors.forename: Ali
authors.initials: A
authors.lastname: Javey
authors.affiliation: Research School of Engineering, The Australian National University (ANU) , Canberra, Australian Capital Territory 0200, Australia.
authors.forename: Andres
authors.initials: A
authors.lastname: Cuevas
keywords: Ohmic contact; electron-selective contact; magnesium fluoride; silicon solar cell; surface passivation