Interdigitated back contact silicon heterojunction solar cells featuring an interband tunnel junction enabling simplified processing

B. Paviet-Salomon*, A. Tomasi, D. Lachenal, N. Badel, G. Christmann, L. Barraud, A. Descœudres, J. Geissbühler, A. Faes, Q. Jeangros, J. P. Seif, S. Nicolay, B. Strahm, S. De Wolf, C. Ballif, M. Despeisse

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


This paper reports on the development of an innovative back-contacted crystalline silicon solar cell with passivating contacts featuring an interband tunnel junction at its electron-collecting contacts. In this novel architecture, named “tunnel-IBC” both the hole collector patterning and its alignment to the electron collector are eliminated, thus drastically simplifying the process flow. However, two prerequisites have to be fulfilled for such devices to work efficiently, namely (i) lossless carrier transport through the tunnel junction and (ii) low lateral conductance within the hole collector in order to avoid shunts with the neighboring electron-collecting regions. We meet these two contrasting requirements by exploiting the anisotropic and substrate-dependent growth mechanism of n- and p-type hydrogenated nano-crystalline silicon layers. We investigate the influence of the deposition temperature and the doping gas concentration on the structural and the selectivity properties of these layers. Eventually, tunnel-IBC devices integrating hydrogenated nano-crystalline silicon layers demonstrate a conversion efficiency up to 23.9%.

Original languageEnglish (US)
Pages (from-to)60-67
Number of pages8
StatePublished - Nov 15 2018

Bibliographical note

Funding Information:
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 727523 . The authors also wish to thank the Interdisciplinary Centre for Electron Microscopy of EPFL for FIB and TEM access.

Publisher Copyright:
© 2018 Elsevier Ltd


  • Interdigitated back contact
  • Passivating contacts
  • Silicon solar cells
  • Tunnel junction

ASJC Scopus subject areas

  • Materials Science(all)
  • Renewable Energy, Sustainability and the Environment


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