Oxidative Segregation of Group V Dopants in CdTe Solar Cells

Craig Perkins, Deborah McGott, Matthew Reese, Wyatt Metzger, Brian McCandless

Research output: Contribution to conferencePaperpeer-review

4 Scopus Citations


Transparent conductive oxides are used in many technologies and it is important to understand their interfacial chemical reactions. Here, we use recently developed thermomechanical cleaving and X-ray photoelectron spectroscopy to probe oxidation states at the SnO2 interface of CdTe solar cells. We show that tin oxide promotes the formation of nanometer-scale oxides of tellurium and sulfur, largely during CdCl2/O2 activation. Surprisingly, in copper-doped devices, relatively low temperature anneals (180-260 °C) to diffuse and activate copper acceptors also cause significant oxidation changes at the front interface, providing a heretofore missing aspect of how back contact processes can modify device transport, recombination, and performance. For Group V-doped devices, this same oxidation process causes segregation of the dopants to the SnO2 interface in their oxidized states, implying that adjacent regions in the absorber have been depleted of dopants. Intriguingly, we demonstrate that because of their layered, van der Walls-bonded crystal structure, spatially segregated Group V oxides may represent a mechanically weak layer in a finished device.

Original languageAmerican English
Number of pages4
StatePublished - Jun 2019
Event46th IEEE Photovoltaic Specialists Conference, PVSC 2019 - Chicago, United States
Duration: 16 Jun 201921 Jun 2019


Conference46th IEEE Photovoltaic Specialists Conference, PVSC 2019
Country/TerritoryUnited States

Bibliographical note

Publisher Copyright:
© 2019 IEEE.

NREL Publication Number

  • NREL/CP-5K00-74084


  • CdTe
  • chemical analysis
  • interface states
  • nanostructures
  • thin film devices


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