Sub-Bandgap Luminescence from Doped Polycrystalline and Amorphous Silicon Films and Its Application to Understanding Passivating-Contact Solar Cells

Harvey Guthrey, Mowafak Al-Jassim, Hieu Nguyen, Anyao Liu, Di Yan, Thien Truong, Mike Tebyetekerwa, Ziyuan Li, Zhuofeng Li, Andres Cuevas, Daniel Macdonald

Research output: Contribution to journalArticlepeer-review

17 Scopus Citations

Abstract

We report luminescence phenomena from doped polycrystalline silicon (poly-Si) films and their applications to study carrier transport properties in passivating-contact solar cells. Low-temperature luminescence spectra emitted from doped poly-Si layers are found to be very broad and stretched from the crystalline silicon (c-Si) luminescence peak to significantly lower energies. This suggests that these layers contain radiative defect levels whose energies are continuously distributed from the band edges to deep levels in the poly-Si bandgap. Moreover, photoinduced carriers inside poly-Si layers are found to be completely blocked by an ultrathin SiOx interlayer (∼1.3 nm). This demonstrates that there is no free-carrier coupling from poly-Si layers in practical passivating-contact solar cells. Finally, we demonstrate that the same principle can be applied to study carrier transport properties in hydrogenated amorphous silicon films.

Original languageAmerican English
Pages (from-to)6619-6625
Number of pages7
JournalACS Applied Energy Materials
Volume1
Issue number11
DOIs
StatePublished - 26 Nov 2018

Bibliographical note

Publisher Copyright:
© Copyright 2018 American Chemical Society.

NREL Publication Number

  • NREL/JA-5K00-75993

Keywords

  • amorphous silicon
  • luminescence
  • passivating contacts
  • polycrystalline silicon
  • solar cells
  • sub-bandgap

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