Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 67: Theory: General
O 67.2: Poster
Wednesday, March 9, 2016, 18:15–20:30, Poster A
Interplay of structural and electronic properties in thin-film absorbers — •Thomas Bischoff1, Claudia Schnohr2, and Silvana Botti1 — 1Institut für Festkörpertheorie und theoretische Optik, 07743 Jena, Germany — 2Institut für Festkörperphysik, 07743 Jena, Germany
During the past years, Cu(In,Ga)(Se,S)2 (CIGS) thin-film solar cells have emerged as a technology that could challenge the current hegemony of silicon solar panels. CIGS compounds conserve to a very high degree their electronic properties in a large non-stoichiometric range and are remarkably insensitive to radiation damage or impurities. The family of kesterites Cu2ZnSe(S,Se)4 (CZTS) exhibits very similar electronic properties. Moreover, kesterites have the clear advantage of being composed of abundant, non-toxic, less expensive chemical elements. However, the efficiency of CZTS solar cells is about 50% smaller than the one of CIGS solar cells.
The origin of the exceptional electronic properties and the defect physics of these compounds and their alloys is still far from being completely understood, despite the large amount of experimental and theoretical work dedicated to that purpose.
We present here self-consistent GW calculations of the dependence of the band gap on internal distortions. Combined with EXAFS measurements, our calculations allow to quantify the structural contributions to the band gap bowing of alloys of these families.