Ludwig, Christian D. R.; Gruhn, Thomas; Felser, Claudia; Schilling, Tanja; Windeln, Johannes; Kratzer, Peter:

Indium-Gallium Segregation in CuIn_xGa_{1-x}Se_2: Ab Initio–Based Monte Carlo Study

In: Physical Review Letters, Jg. 105 (2010) ; Nr. 2, S. 025702/1-4
ISSN: 0031-9007
Zeitschriftenaufsatz / Fach: Physik
Abstract:
Thin-film solar cells with CuIn_xGa_{1-x}Se_2 (CIGS) absorber are still far below their efficiency limit,
although lab cells already reach 20.1%. One important aspect is the homogeneity of the alloy. Large-scale
simulations combining Monte Carlo and density functional calculations show that two phases coexist in
thermal equilibrium below room temperature. Only at higher temperatures, CIGS becomes more and more
a homogeneous alloy. A larger degree of inhomogeneity for Ga-rich CIGS persists over a wide
temperature range, which contributes to the observed low efficiency of Ga-rich CIGS solar cells