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Optical characterisation of silicon nanocrystals embedded in SiO2/Si3N4 hybrid matrix for third generation photovoltaics

Dawei Di*, Heli Xu, Ivan Perez-Wurfl, Martin A Green and Gavin Conibeer

Author Affiliations

ARC Photovoltaics Centre of Excellence, University of New South Wales, Sydney, NSW 2052, Australia

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Nanoscale Research Letters 2011, 6:612  doi:10.1186/1556-276X-6-612

Published: 3 December 2011


Silicon nanocrystals with an average size of approximately 4 nm dispersed in SiO2/Si3N4 hybrid matrix have been synthesised by magnetron sputtering followed by a high-temperature anneal. To gain understanding of the photon absorption and emission mechanisms of this material, several samples are characterised optically via spectroscopy and photoluminescence measurements. The values of optical band gap are extracted from interference-minimised absorption and luminescence spectra. Measurement results suggest that these nanocrystals exhibit transitions of both direct and indirect types. Possible mechanisms of absorption and emission as well as an estimation of exciton binding energy are also discussed.

silicon nanocrystals; third generation photovoltaics; absorption coefficient; photoluminescence; band gap extraction