Photoluminescence studies of polycrystalline Cu(In,Ga)Se{sub 2}: Lateral inhomogeneities beyond Abbe's diffraction limit
- Institut für Physik, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg (Germany)
- Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), Industriestraße 6, 70565 Stuttgart (Germany)
We analyze Cu(In,Ga)Se{sub 2} absorbers with a scanning near-field optical microscope (SNOM) by photoluminescence (PL). Such measurements allow one to extract local fluctuations of the integral PL yield, the quasi-Fermi level splitting, and the material composition in the submicron range. However, the experimental findings depend strongly on the surface roughness of the absorber: If the surface is rough, artifact-prone correlations between surface contour and PL features measured by SNOM can be found that complicate the study of recombination effects. For smooth surfaces, such correlations no longer exist and the influence of grain boundaries on the integral PL yield and the quasi-Fermi level splitting is revealed. The method also allows a detailed determination of the local band gaps in neighboring grains and their spatial variation inside, and thus of possibly local changes in chemical composition of different grains.
- OSTI ID:
- 22492929
- Journal Information:
- Journal of Applied Physics, Vol. 118, Issue 18; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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