Strain Mapping of CdTe Grains in Photovoltaic Devices

Irene Calvo-Almazan, Xiaojing Huang, Hanfei Yan, Evgeny Nazaretski, Yong S. Chu, Stephan O. Hruszkewycz, Michael Elias Stuckelberger*, Andrew P. Ulvestad, Eric Colegrove, Tursun Ablekim, Martin V. Holt, Megan O. Hill, Siddharth Maddali, Lincoln J. Lauhon, Mariana I. Bertoni

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Strain within grains and at grain boundaries (GBs) in polycrystalline thin-film absorber layers limits the overall performance because of higher defect concentrations and band fluctuations. However, the nanoscale strain distribution in operational devices is not easily accessible using standard methods. X-ray nanodiffraction offers the unique possibility to evaluate the strain or lattice spacing at nanoscale resolution. Furthermore, the combination of nanodiffraction with additional techniques in the framework of multimodal scanning X-ray microscopy enables the direct correlation of the strain with material and device parameters such as the elemental distribution or local performance. This approach is applied for the investigation of the strain distribution in CdTe grains in fully operational photovoltaic solar cells. It is found that the lattice spacing in the (111) direction remains fairly constant in the grain cores but systematically decreases at the GBs. The lower strain at GBs is accompanied by an increase of the total tilt. These observations are both compatible with the inhomogeneous incorporation of smaller atoms into the lattice, and local stress induced by neighboring grains.

Original languageEnglish (US)
Article number8862942
Pages (from-to)1790-1799
Number of pages10
JournalIEEE Journal of Photovoltaics
Volume9
Issue number6
DOIs
StatePublished - Nov 2019

Keywords

  • CdTe
  • X-ray
  • X-ray beam induced current (XBIC)
  • X-ray diffraction (XRD)
  • X-ray fluorescence (XRF)
  • X-ray microscopy
  • multimodal
  • nanodiffraction
  • photovoltaic
  • solar cells
  • strain

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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