Sub-Stochiometric Nickel Oxide Hole-Selective Contacts in Solar Cells: Comparison of Simulations and Experiments with Sputtered Films

Mrutyunjay Nayak, Kristin Bergum, George E. Stan, In Hwan Lee, Andrej Kuznetsov

Research output: Contribution to journalArticlepeer-review


Sub-stochiometric nickel oxide (NiOx) films were investigated as a hole selective contact option in silicon (Si) heterojunction solar cells. Numerical simulations were carried out to evaluate the impacts of the NiOx electronic properties variations and the NiOx/Si interface defect density (Dit) on device performance. Simulation data suggest that the best performance is achievable for wide bandgaps (Eg) and corresponding high valence band edge (EVB) positions in the NiOx films. Overall, in simulations, the performance remains practically unchanged for the nickel vacancy concentrations [VNi] = 1017–1021cm−3, assuming high EVB and low Dit. The experimental data measured using NiOx films prepared by radio-frequency magnetron sputtering reveal that the increase in [VNi] lifts the conductivity, concurrently decreasing Eg and EVB. As a result, we concluded that the performance of the fabricated sputtered NiOx/Si heterojunction solar cell is limited by high Dit as well as narrow Eg and low EVB.

Original languageEnglish
Article number2200651
JournalPhysica Status Solidi (A) Applications and Materials Science
Issue number10
Publication statusPublished - 2023 May

Bibliographical note

Funding Information:
The research leading to these results has received funding from the EEA grant 2014–2021, under project contract no. 36/2021 (project code: EEA‐RO‐NO‐2018‐0106). The Research Council of Norway is acknowledged for support to the Norwegian Micro‐ and Nano‐Fabrication Facility, NorFab, project number 295864. The international collaboration was enabled through the INTPART and UTFORSK Programs at the Research Council of Norway and the Directorate for Higher Education and Skills in Norway (NEARTEMS project number 322382 and SPECTRINKO project number UTF‐2021/10210).

Publisher Copyright:
© 2023 Wiley-VCH GmbH.


  • carrier selective contacts
  • magnetron sputtering
  • nickel oxide
  • silicon heterojunction solar cells
  • simulations

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Materials Chemistry
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering
  • Surfaces and Interfaces


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