| AVS 61st International Symposium & Exhibition | |
| Atom Probe Tomography Focus Topic | Thursday Sessions |
| Session AP+AS+MC+NS+SS-ThM |
| Session: | APT Analysis of Semiconductors, Magnetic and Oxide Materials |
| Presenter: | Oana Cojocaru-Mirédin, Max Planck Institut fur Eisenforschung GmbH, Germany |
| Authors: | O. Cojocaru-Mirédin, Max Planck Institut fur Eisenforschung GmbH, Germany R. Würz, Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg, Germany D. Raabe, Max Planck Institut fur Eisenforschung GmbH, Germany |
| Correspondent: | Click to Email |
Cu(In,Ga)Se2 (CIGS), Cu2ZnSnSe4 (CZTSe), and multicrystalline Si (mc-Si) solar cells possess a high efficiency [1], despite the polycrystalline structure of the absorber layer. One of the major factors controlling the cell efficiency is the diffusion of the impurities during the fabrication process into the absorber layer and to the p-n junction [2]. However, the interaction between the defects and the impurities at the internal interfaces is not completely understood. This is due to a lack of information on the local chemical changes across the internal interfaces at the nanoscale.
As a step towards a better understanding of the impurity redistribution at the internal interfaces, we have developed novel approaches of preparing site-specific atom probe specimens using combined focused ion beam (FIB), (scanning) transmission electron microscopy ((S)TEM) and electron backscattered diffraction (EBSD). These approaches allow selected GBs in polycrystalline CIGS, CZTSe and mc-Si layers to be studied by atom probe tomography (APT).
Several examples of correlative EBSD-TEM-APT (see Figure 1) and STEM-APT (see Figure 2) studies will be presented in this work. Using APT, segregation of impurities at the GBs was directly observed. APT data of various types of GBs will be presented and discussed with respect to the possible effects on the cell efficiency.
[1] Empa [Internet]. Empa.ch: A new world record for solar cell efficiency, 2013. Available from: http://www.empa.ch/plugin/template/empa/3/131438/---/l=2 [cited 2013 January 18].
[2] J. L. Shay, S. Wagner, H. M. Kasper, Appl. Phys. Lett. 27 (1975) 89, S. Yip and I. Shih, Proceedings of the 1st World Conference on Photovoltaic Energy Conversion (IEEE, Piscataway, 1994), p.210.