Amorphous silicon passivated contacts for diffused junction silicon solar cells

J. Bullock, D. Yan, Y. Wan, A. Cuevas, B. Demaurex, A. Hessler-Wyser, S. De Wolf

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

Carrier recombination at the metal contacts is a major obstacle in the development of high-performance crystalline silicon homojunction solar cells. To address this issue, we insert thin intrinsic hydrogenated amorphous silicon [a-Si:H(i)] passivating films between the dopant-diffused silicon surface and aluminum contacts. We find that with increasing a-Si:H(i) interlayer thickness (from 0 to 16 nm) the recombination loss at metal-contacted phosphorus (n +) and boron (p+) diffused surfaces decreases by factors of ∼25 and ∼10, respectively. Conversely, the contact resistivity increases in both cases before saturating to still acceptable values of ∼ 50 mΩ cm2 for n+ and ∼100 mΩ cm2 for p+ surfaces. Carrier transport towards the contacts likely occurs by a combination of carrier tunneling and aluminum spiking through the a-Si:H(i) layer, as supported by scanning transmission electron microscopy-energy dispersive x-ray maps. We explain the superior contact selectivity obtained on n+ surfaces by more favorable band offsets and capture cross section ratios of recombination centers at the c-Si/a-Si:H(i) interface.

Original languageEnglish (US)
Article number163703
JournalJournal of Applied Physics
Volume115
Issue number16
DOIs
StatePublished - Apr 28 2014

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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