Abstract
Implementation of an optically active material on silicon has been a persistent technological challenge. For tandem photovoltaics using a Si bottom cell, as well as for other optoelectronic applications, there has been a longstanding need for optically active, wide band gap materials that can be integrated with Si. ZnSiP2 is a stable, wide band gap (2.1 eV) material that is lattice matched with silicon and comprised of inexpensive elements. As we show in this paper, it is also a defect-tolerant material. Here, we report the first ZnSiP2 photovoltaic device. We show that ZnSiP2 has excellent photoresponse and high open circuit voltage of 1.3 V, as measured in a photoelectrochemical configuration. The high voltage and low band gap-voltage offset are on par with much more mature wide band gap III-V materials. Photoluminescence data combined with theoretical defect calculations illuminate the defect physics underlying this high voltage, showing that the intrinsic defects in ZnSiP2 are shallow and the minority carrier lifetime is 7 ns. These favorable results encourage the development of ZnSiP2 and related materials as photovoltaic absorber materials.
Original language | English |
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Pages (from-to) | 1031-1041 |
Number of pages | 11 |
Journal | Energy and Environmental Science |
Volume | 9 |
Issue number | 3 |
DOIs | |
State | Published - Mar 2016 |
Externally published | Yes |
Funding
The authors thank Anna Duda for depositing electrical contacts. Funding for this work was provided by the National Renewable Energy Laboratory through the Laboratory-Directed Research and Development program and by the National Science Foundation through the Renewable Energy Materials Research and Engineering Center at the Colorado School of Mines under NSF grant number DMR-0820518. RTM acknowledges NSF CAREER Award 1541230 for support of this work. KAB is thankful for funding from the Danish Council for Independent Research (DFF), grant no. 4090-00071, and the DFF Sapere Aude program. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes.