Dresden 2014 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 71: Energy materials: Silicon-based photovoltaics

HL 71.3: Vortrag

Mittwoch, 2. April 2014, 15:30–15:45, POT 151

Electronic properties of nano-textured `black` silicon — •Manuel Salzberger, Michael Algasinger, Svetoslav Koynov, and Martin Stutzmann — Walter Schottky Institut, Technische Universität München, 85748 Garching, Germany

Nano-textured silicon, also referred to as black silicon (b-Si), shows a reflectivity below 5% in the whole range of Si absorption [1]. Furthermore, the nano-texture exhibits efficient light trapping effects, making it interesting for application in thin film solar cells. However, all black Si solar cells reported up to now show a poor external quantum efficiency in the short wavelength range due to elevated surface recombination. Besides the enlarged surface area, also the potential distribution within the nano-texture can affect the recombination rate.

Electrical measurements of nano-textured thin Si films were performed in order to investigate the influence of the structure depth on the electronic properties. The b-Si nano-textures were prepared with an Au-catalyzed wet-chemical etch process. Cross-sectional scanning electron microscopy images show a nano-texture consisting of c-Si hillocks, reaching deep into the substrate. From the comparison with a planar reference sample, the influence of the nano-texture on the electrical conductivity will be investigated. From these findings, a better knowledge of the potential distribution within the nano-texture and, thus, a possible reduction of the surface recombination can be realized.

[1] S. Koynov, M. S. Brandt, and M. Stutzmann, Appl. Phys. Lett. 88, 203107 (2006).