Journal article

Calcium contacts to n-type crystalline silicon solar cells

Thomas G Allen, James Bullock, Peiting Zheng, Ben Vaughan, Matthew Barr, Yimao Wan, Christian Samundsett, Daniel Walter, Ali Javey, Andres Cuevas



Direct metallization of lightly doped n-type crystalline silicon (c-Si) is known to routinely produce non-Ohmic (rectifying) contact behaviour. This has inhibited the development of n-type c-Si solar cells with partial rear contacts, an increasingly popular cell design for high performance p-type c-Si solar cells. In this contribution we demonstrate that low resistance Ohmic contact to n-type c-Si wafers can be achieved by incorporating a thin layer of the low work function metal calcium (ϕ ~2.9 eV) between the silicon surface and an overlying aluminium capping layer. Using this approach, contact resistivities of ρc ~ 2 mΩcm2 can be realised on undiffused n-type silicon, thus enabling partia..

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Funding Acknowledgements

This work was performed in part at the Materials node of the Australian National Fabrication Facility, which is a company established under the National Collaborative Research Infrastructure Strategy to provide nano-fabrication and micro-fabrication facilities for Australia's researchers. This work has been supported by the Australian government through the Australian Renewable Energy Agency (ARENA). The work at the University of California, Berkeley was supported by the Bay Area Photovoltaic Consortium (BAPVC).