Regensburg 2013 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 46: Photovoltaics (joint session HL/CPP/O)

CPP 46.11: Vortrag

Freitag, 15. März 2013, 12:00–12:15, H2

Surface Modification of Nano-Textured Black Silicon for Photovoltaic Applications — •Michael Algasinger¹, Svetoslav Koynov¹, Julie Paye¹, Florian Werner², Max Bernt¹, Martin S. Brandt¹, and Martin Stutzmann¹ — ¹Walter Schottky Institut, Technische Universität München, 85748 Garching, Germany — ²Institute for Solar Energy Research Hamelin, Am Ohrberg 1, 31860 Emmerthal, Germany

The morphology and the electronic properties of nano-textured silicon, obtained by a metal-catalyzed wet etching process and its improvement by an additional chemical treatment are examined with regard to solar cell applications. Photoluminescence and optical reflectivity measurements show evidence for a nano-porous silicon (np-Si) phase in the as-prepared nanostructure. It is found that an additional wet-chemical treatment removes the np-Si fraction and significantly alters the surface of the nanostructure. Cross-sectional scanning electron microscopy images reveal a drastic reduction of the surface area, to values of only 3 - 6 times of that of a planar surface. Electron spin resonance measurements were performed to investigate the type and quantity of defects induced by the nano-texturing process. First results on the passivation of surface defects via atomic layer deposition of Al₂O₃ are presented. Photoconductance decay measurements of passivated nanostructures, which received the additional post-etching treatment, show a significant increase in effective carrier lifetimes.