Passivated contacts to n+ and p+ silicon based on amorphous silicon and thin dielectrics
Date
2014
Authors
Bullock, James
Yan, Di
Cuevas, Andres
Demaurex, Benedicte
Hessler-Wyser, Aicha
De Wolf, Stefaan
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IEEE
Abstract
Carrier recombination at the metal contact regions has now become a critical obstacle to the advancement of high efficiency diffused junction silicon solar cells. The insertion of a thin dielectric interlayer - forming a metal-insulator-semiconductor (MIS) contact - is a known approach to reduce contact recombination. However, an insulator thickness less than 25 Å is usually required for current transport, making it difficult to simultaneously achieve good surface passivation. This paper compares standard MIS contacts to a newly developed contact structure, involving hydrogenated amorphous silicon (a-Si:H) over-layers. The contact structures are trialed on both n+ and p+ lightly diffused surfaces, with SiO2 and Al2O3 insulator layers, respectively. In both cases significant improvements in the carrier-selectivity of the contacts is achieved with the addition of the a-Si:H over-layers. Simulations of idealized cell structures are used to highlight the performance and technological benefits of these carrier-selective structures over standard locally diffused contacts.
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Source
2014 IEEE 40th Photovoltaic Specialist Conference, PVSC 2014
Type
Conference paper
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2037-12-31