Simsek Sanli, E.; Ramasse, Q.M.; Sigle, W.; Abou-Ras, D.; Mainz, R.; Weber, A.; Kleebe, H.-J.; van Aken, P.: Elemental redistributions at structural defects in Cu(In,Ga)Se2 thin films for solar cells. Journal of Applied Physics 120 (2016), p. 205301/1-7
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The microstructural evolution of Cu(In,Ga)Se2 absorber layers during a three-stage-type coevaporation process was studied to elucidate the effect of a Cu-rich stage on the formation of extended structural defects. Defect densities for two Cu-poor samples, one interrupted before and one after this crucial Cu-rich composition stage, were investigated by scanning transmission electron microscopy (STEM) imaging. The structure and chemical nature of individual defects were investigated by aberration-corrected high-resolution STEM in combination with electron energy-loss spectroscopy on the atomic-scale. In spite of the different defect densities between the two samples, most of the individual defects exhibited similar chemistry. In particular, the elemental distributions ofatomic columns at {112} twin planes, which are very frequent in Cu(In,Ga)Se2 thin films, were found to be the same as in the defect-free grain interiors. In contrast, within grain boundaries, dislocation cores, and other structurally more complex defects, elemental redistributions of Cu and In were observed. VC 2016 Author(s). All article content, except where otherwise noted, is licensed under aCreative Commons Attribution (CC BY) license (