Efficiency increasing and cost reduction are key concepts in the development of the photovoltaic field and one of the factors responsible for power loss in single bandgap solar cells is that, for photons with energy higher than the band gap, the excess energy is lost by thermalization. One way to overcome this limit is to introduce the multijunction concept, where the device has more than one bandgap . In this framework, silicon nanocrystals (Si NCs) embedded in a dielectric matrix were proposed as absorbers in all-Si multi-junction solar cells thanks to the quantum confinement capability of the Si NCs, that allows a better match with the solar spectrum [2, 3]. SiC as a dielectric matrix is considered promising thanks to its better conduction properties and lower barrier to the Si NCs with respect to eg SiO2 . Current-Atomic Force Microscopy (c-AFM) is widely used to determine the local electrical properties of semiconducting thin films at the nanoscale . A conductive probe is put in contact with the surface and the current flowing between the tip and the sample is measured at constant bias . In the present contribution c-AFM has been used to characterize features related to Si NC clusters in SiC on a local scale, giving a fundamental insight on their properties at microscopical level.
31 Mar 2014
Volume: 21 Issue: 1 Pages: 33-34