In this paper we demonstrate the parallel application of light beam induced current (LBIC) and lock-in infrared thermography for the investigation of strong shunting regions in multicrystalline silicon solar cells. Usually both mappings are not correlated, but in this case the shunts could be imaged by both techniques. If for a locally generated photocurrent the conductance through a shunt lying nearby is comparable to that across the emitter into the current amplifier, local shunts become visible in the LBIC as dark regions. After the rear contact of the cell was removed, the LBIC technique was performed from the rear side of the cell. The images point to the existence of inversion layers along grain boundaries crossing the bulk of the cell. Obviously, these inversion layers represent the dominant material-induced shunt type in multicrystalline silicon solar cells. Moreover, it has been shown that cracks may lead to shunts.
A complete study of the optical properties has been achieved for hydrogenated silicon nitride SiN,:H obtained by either Low Frequency (40kHz) Plasma Enhanced Chemical Vapour Deposition (LF-PECVD) or by another low temperature deposition technique: UltraViolet photoassisted CVD (UVCVD). Spectroscopic ellipsometry measurements were carried out on a large number of samples. The results were gathered in a data library in order to compute the wavelength-dependant reflection, absorption and transmission coefficients through the layers. Different optical behaviors were observed according to the deposition technique, with stronger absorption and hence smaller optical gaps for UVCVD films. This is believed to be due to the formation in the SIN, matrix of amorphous silicon (a-Si) clusters, which seem to be much bigger than those obtained in PECVD layers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.