Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 38: Photovoltaics: CIGS and related Materials
HL 38.8: Vortrag
Dienstag, 27. März 2012, 13:00–13:15, ER 270
Investigations of vertical chemical gradients in Cu(In,Ga)S2- thin films prepared by sulfurization of sputtered precursor layers using highly spatially resolved cathodoluminescence microscopy — •Stefan Ribbe1, Mathias Müller1, Frank Bertram1, Thomas Hempel1, Humberto Rodriguez-Alvarez2, Jakob Lauche2, Hans Werner Schock2, and Jürgen Christen1 — 1Institute for Experimental Physics, Otto-von-Guericke-University Magdeburg, Germany — 2Helmholtz Center Berlin for Materials and Energy, Germany
The luminescence properties of Cu(In,Ga)S2(CIGS)-absorber layers for thin film solar cells have been studied by highly spatially resolved cathodoluminescence (CL) at low temperature (T=5 K). In/Cu-Ga-precursors were annealed with elementary sulfur pellets in a rapid thermal process at different annealing times to represent different growth steps of the CIGS absorber layer. Spatially integral CL spectra show a dominant peak at 825 nm accompanied by a low-energy shoulder at 890 nm. Only a slight blue shift of the main peak is observed by variation of the excitation density. Investigations of cross-sections show for all samples a similar luminescence distribution. Near the molybdenum back contact distinct areas show luminescence emitting at 680−750 nm. In contrast, in upper regions of the layer a homogeneous low-energy luminescence at around 820 nm is observed which exhibits the most intensive spots on the cross-section. In local spectra we observe a change of the dominant recombination channel at the interface of these two regions.