On the oxidation mechanism of microcrystalline silicon thin films studied by Fourier transform infrared spectroscopy

Journal article (2011)

Authors

AC Bronneberg External organisation
A.H.M. Smets Photovoltaic Materials and Devices - EEMCS
M Creatore External organisation
MCM van de Sanden External organisation
Research Group
Photovoltaic Materials and Devices (EEMCS) (TU Delft)
More Info
expand_more

Published Date

2011

Language

English

Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Electrical Sustainable Energy

Research Group

Photovoltaic Materials and Devices

Abstract

Insight into the oxidation mechanism of microcrystalline silicon thin films has been obtained by means of Fourier transform infrared spectroscopy. The films were deposited by using the expanding thermal plasma and their oxidation upon air exposure was followed in time. Transmission spectra were recorded directly after deposition and at regular intervals up to 8 months after deposition. The interpretation of the spectra is focused on the Si¿Hx stretching (2000¿2100 cm¿1), Si¿O¿Si (1000¿1200 cm¿1), and OxSi¿Hy modes (2130¿2250 cm¿1). A short time scale (<3 months) oxidation of the crystalline grain boundaries is observed, while at longer time scales, the oxidation of the amorphous tissue and the formation of O¿H groups on the grain boundary surfaces play a role. The implications of this study on the quality of microcrystalline silicon exhibiting no post-deposition oxidation are discussed: it is not sufficient to merely passivate the surface of the crystalline grains and fill the gap between the grains with amorphous silicon. Instead, the quality of the amorphous silicon tissue should also be taken into account, since this oxidation can affect the passivating properties of the amorphous tissue on the surface of the crystalline silicon grains.