Mainz, RolandSanli, Ekin SimsekStange, HelenaAzulay, DoronBrunken, StephanGreiner, DieterHajaj, ShirHeinemann, Marc D.Kaufmann, Christian A.Klaus, ManuelaRamasse, Quentin M.Rodriguez-Alvarez, HumbertoWeber, AlfonsBalberg, IsaacMillo, OdedAken, Peter A. vanAbou-Ras, Daniel2017-10-242017-10-2420161754-5692https://depositonce.tu-berlin.de/handle/11303/6906http://dx.doi.org/10.14279/depositonce-6245Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.In polycrystalline semiconductor absorbers for thin-film solar cells, structural defects may enhance electron-hole recombination and hence lower the resulting energy conversion efficiency. To be able to efficiently design and optimize fabrication processes that result in high-quality materials, knowledge of the nature of structural defects as well as their formation and annihilation during film growth is essential. Here we show that in co-evaporated Cu(In,Ga)Se-2 absorber films the density of defects is strongly influenced by the reaction path and substrate temperature during film growth. A combination of high-resolution electron microscopy, atomic force microscopy, scanning tunneling microscopy, and X-ray diffraction shows that Cu(In,Ga)Se-2 absorber films deposited at low temperature without a Cu-rich stage suffer from a high density of - partially electronically active - planar defects in the {112} planes. Real-time X-ray diffraction reveals that these faults are nearly completely annihilated during an intermediate Cu-rich process stage with [Cu]/([In] + [Ga]) > 1. Moreover, correlations between real-time diffraction and fluorescence analysis during Cu-Se deposition reveal that rapid defect annihilation starts shortly before the start of segregation of excess Cu-Se at the surface of the Cu(In,Ga)Se-2 film. The presented results hence provide direct insights into the dynamics of the film-quality-improving mechanism.en690 Hausbau, BauhandwerkArticle1754-5706