Ga composition dictates macroscopic photovoltaic and nanoscopic electrical characteristics of Cu(In 1-XGa X)Se 2 thin films via grain-boundary-type inversion

Wenjie Li, Sidney R. Cohen, Konstantin Gartsman, David Cahen

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

The photovoltaic performance of solar cells, based on a Cu(In 1-xGa x)Se 2 (CIGS) absorber layer, is directly correlated with Ga composition. We have used scanning capacitance microscopy and conducting probe atomic force microscopy (CP-AFM) to provide microscopic electrical characterization of CIGS films with different Ga content. We found p- to n-type inversion at grain boundaries of the polycrystalline CIGS film, especially for Ga-poor compositions. The fraction of grain boundaries undergoing inversion dramatically decreased for Ga compositions above x = 0.32, the composition corresponding to a sharp efficiency drop of the complete cells. CP-AFM measurements showed a marked current drop at grain boundaries as the Ga composition rose above x = 0.32.

Original languageEnglish
Article number6165321
Pages (from-to)191-195
Number of pages5
JournalIEEE Journal of Photovoltaics
Volume2
Issue number2
DOIs
StatePublished - 2012
Externally publishedYes

Funding

Manuscript received October 27, 2011; revised December 19, 2011; accepted January 1, 2012. Date of publication March 6, 2012; date of current version March 16, 2012. This work was supported by the German Ministry for Environment under Contract #0327559H, by the G. M. J. Schmidt Minerva Centre for Supramolecular Architecture, and by the Kimmel Centre for Nanoscale Science. D. Cahen holds the Schaefer Chair in Energy Research.

FundersFunder number
German Ministry for Environment0327559H
Kimmel Centre for Nanoscale Science

    Keywords

    • Conducting probe atomic force microscopy (CP-AFM)
    • Ga content
    • photovoltaics
    • scanning capacitance microscopy (SCM)
    • solar cells
    • type inversion

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