Obtaining Large Columnar CdTe Grains and Long Lifetime on CdSe, MgZnO, or CdS Layers

Mahisha Amarasinghe, Eric Colegrove, John Moseley, Helio Moutinho, David Albin, Joel Duenow, Mowafak Al-Jassim, Wyatt Metzger, Jason Kephart, Walajabad Sampath, Siva Sivananthan

Research output: Contribution to journalArticlepeer-review

54 Scopus Citations


CdTe solar cells have reached efficiencies comparable to multicrystalline silicon and produce electricity at costs competitive with traditional energy sources. Recent efficiency gains have come partly from shifting from the traditional CdS window layer to new materials such as CdSe and MgZnO, yet substantial headroom still exists to improve performance. Thin film technologies including Cu(In,Ga)Se2, perovskites, Cu2ZnSn(S,Se)4, and CdTe inherently have many grain boundaries that can form recombination centers and impede carrier transport; however, grain boundary engineering has been difficult and not practical. In this work, it is demonstrated that wide columnar grains reaching through the entire CdTe layer can be achieved by aggressive postdeposition CdTe recrystallization. This reduces the grain structure constraints imposed by nucleation on nanocrystalline window layers and enables diverse window layers to be selected for other properties critical for electro-optical applications. Computational simulations indicate that increasing grain size from 1 to 7 µm can be equivalent to decreasing grain-boundary recombination velocity by three orders of magnitude. Here, large high-quality grains enable CdTe lifetimes exceeding 50 ns.

Original languageAmerican English
Article number1702666
Number of pages9
JournalAdvanced Energy Materials
Issue number11
StatePublished - 2018

Bibliographical note

Publisher Copyright:
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

NREL Publication Number

  • NREL/JA-5K00-68612


  • CdTe
  • grain boundaries
  • recombination
  • solar energy
  • thin films


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