Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 12: Photovoltaics (Joint session of HL and DF, organized by HL)
HL 12.9: Vortrag
Montag, 7. März 2016, 17:30–17:45, H2
Optical characterization of Cu(In,Ga)Se2 with highly spatially, spectrally, and time resolved cathodoluminescence — •Martin Müller1, Mathias Müller1, Frank Bertram1, Jürgen Christen1, Torsten Hölscher2, Setareh Zahedi-Azad2, Matthias Maiberg2, and Roland Scheer2 — 1Institute of Experimental Physics, Otto-von-Guericke-University, Germany — 2Martin-Luther-University Halle-Wittenberg, Germany
Potential fluctuations and transport parameters are important factors to further improve efficiencies of Cu(In,Ga)Se2 (CIGSe)solar cells. Optical properties of CIGSe absorbers have been studied by means of highly spatially and spectrally resolved cathodoluminescence (CL) to investigate lateral fluctuations and transport parameters. The measurements were performed from low temperature (T = 4.5 K) up to room temperature. CL spectra recorded at 4.5 K, exhibit a dominant emission at 1.06 eV (1170 nm). A shoulder at 1.14 eV (1090 nm) on the low energy side and at 0.99 eV (1250 nm) on the high energy side were observable. In excitation density dependent CL measurements, a blue shift of 25 meV/decade is observed. Additionally, ps-time resolved CL was performed. A dependence of the initial lifetime of more than one order of magnitude from the emission energy could be observed, illustrating relaxation of charge carriers in potential fluctuations. Investigation of panchromatic temperature dependent initial lifetimes reveals a pronounced increase up to 50 K and a subsequent decrease caused by non-radiative recombination. A concept for optical investigations of transport parameters and first results will be presented.