Dresden 2003 – scientific programme

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HL: Halbleiterphysik

HL 55: Störstellen / Amorphe Halbleiter

HL 55.1: Talk

Friday, March 28, 2003, 11:45–12:00, BEY/154

Electron trapping by excited microvoids - an explanation of the Staebler-Wronski effect — •Krüger Thomas — Theoretische Physik, Fakultät für Naturwissenschaften, Universität Paderborn

The use of amorphous, hydrogenated silicon (a-Si:H) in photovoltaic devices is limited by a severe light-induced degradation which can be reversed by thermal annealing in the dark (Staebler-Wronski effect). Despite a lot of efforts in the past there is no generally accepted idea regarding the mechanism of this process. We present a new proposal relying on the concept of electron trapping by excited microvoids (ETEM). This concept avoids the weaknesses and failings of previous attempts and allows for a reasonable description of the kinetics of the process. Hydrogen diffusion is not necessary, and the findings of light-induced ESR spectroscopy (LESR) fit into our model quite naturally. Results of quantum-chemical calculations indicate that the essential species appearing in the sequence of reaction steps are actually present in a-Si:H.