Evolution of Electronic Properties of Cu(In, Ga)Se2 (CIGS)-Based Solar Cells During a 3-stage Growth Process


We investigated the electronic properties of ZnO/CdS/CIGS/Mo/SLG polycrystalline thin-film solar cells with compositions ranging from Cu-rich to In(Ga)-rich by deep-level transient spectroscopy (DLTS) and capacitance-voltage (C-V) measurements. This compositional change represents the evolution of the film during growth by the 3-stage process. Two sets (four samples each) of CIGS thin films were prepared with Ga/(In+Ga) ratios of ∼0.3 (low Ga) and ∼0.6 (high Ga). The Cu/(In+Ga) ratio ranges from 1.24 (Cu-rich) to 0.88 (In(Ga)-rich). The films were treated with NaCN to remove the Cu2-xSe phase where needed. Key results include: (1) For lowGa devices, DLTS data show that acceptor-like traps dominate in samples where CIGS grains do not go through the Cu-rich to In(Ga)-rich transition, whereas donor-like traps dominate in In(Ga)-rich samples. Therefore, we see a clear transformation of defects from acceptor-like to donor-like traps. The activation energies of these traps range from 0.12 to 0.63 eV. We also observed that NaCN treatment eliminates a deep minority trap in the In(Ga)-rich devices, (2) For high-Ga devices, only majority-carrier traps were detected. These traps again range from shallow to deep, (3) The carrier concentration around the junction and the density of traps decrease as the CIGS becomes more In(Ga)-rich.

This is a preview of subscription content, access via your institution.


  1. 1.

    K. Ramanathan, M. Contreras, C. Perkins, S. Asher, F. Hasoon, J. Keane, D. Young, M. Romero, W. Metzger, R. Noufi, J. Ward, and A. Duda, Prog. Photovolt: Res. Appl. 11, 225 (2003).

    CAS  Article  Google Scholar 

  2. 2.

    U.C. Boehnke and G. Kuhn, J. Mat. Sci. 22, 1635 (1987).

    CAS  Article  Google Scholar 

  3. 3.

    Jehad AbuShama, R. Noufi, Y. Yan, K. Jones, B. Keyes, P. Dippo, M. Romero, M. Al-Jassim, J. Alleman, and D. Williamson, Mat. Res. Soc. Symp. 668, H7.2.1 (2001).

    Article  Google Scholar 

  4. 4.

    A. Jasenek, U. Rau, V. Nadenau, and H. W. Schock, J. Appl. Phys. 87, 594 (2000).

    CAS  Article  Google Scholar 

  5. 5.

    R. Herberholz, M. Igalson, and H. W. Schock, J. Appl. Phys. 83, 321 (1998).

    Article  Google Scholar 

  6. 6.

    D. V. Lang, J. Appl. Phys. 45, 3023 (1974).

    CAS  Article  Google Scholar 

  7. 7.

    Jehad A. AbuShama et al., to be published.

Download references

Author information



Corresponding author

Correspondence to Jehad A. AbuShama.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

AbuShama, J.A., Johnston, S., Ahrenkiel, R. et al. Evolution of Electronic Properties of Cu(In, Ga)Se2 (CIGS)-Based Solar Cells During a 3-stage Growth Process. MRS Online Proceedings Library 763, 525 (2002). https://doi.org/10.1557/PROC-763-B5.25

Download citation