Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 81: Poster: Energy materials incl. photovoltaics

HL 81.4: Poster

Wednesday, April 2, 2014, 17:00–20:00, P1

Black-silicon solar cells — •Philipp Assum, Svetoslav Koynov, and Martin Stutzmann — Walter Schottky Institut , Technische Universität München, Am Coulombwall 4, D-85748 Garching, Germany

Avoiding optical losses is a key issue for the improvement of photovoltaic solar cells. Therefore black nano-textured surfaces are a prospective possibility since they almost completely suppress reflection in the whole range of silicon absorption. Furthermore an enhancement of absorption occurs in thin solar cells due to light trapping effects.

The present work focuses on the application of black-silicon nano-textures to actual solar cells. Common approaches first perform the black nano-texture etch process followed by the formation of the emitter. This is due to the fact that the black etch process is problematic on heavily doped emitter layers which are commonly used for present solar cells. In contrast this work presents a new approach where the sequence of processes is changed. First a deep but weakly doped emitter is created. Subsequently a modified black etch process, which is feasible on the doping level of the emitter, is performed. Self-doping grid contacts are applied to form highly doped regions just in vicinity of the contact which is called the selective emitter concept.

Initial results will be reported in comparison with results concerning "black" solar cells produced by the common approach in which the black etch process precedes the emitter formation.