Silicon nanostructured layers for improvement of silicon solar cells' efficiency: A promising perspective

The photovoltaics industry is dominated by silicon solar cells technology mainly because of the low manufacturing cost. However, these solar cells show an important limiting factor on conversion efficiency due to the inefficient absorption of high energy photons as a consequence of the indirect bandgap structure of bulk silicon. In this article, we discuss about different possibilities to improve the efficiency of solar cells and we propose the use of silicon nanostructured layers to achieve this goal. We present the fabrication methods as well as the characterization results of two kinds of layers which can be used for solar cells' efficiency improvement, namely non-stoichiometric silica layers (SiOx) and nonstoichiometric silicon nitride layers (SiNx) We demonstrate that the photoluminescence (PL) properties and/or the increased photocurrent (PC) signal at high-energy photon could be used to improve this efficiency. Finally, the major asset of these methods lies in their possibility to be incorporated to the solar cell processing for an insignificant cost. (c) 2005 Published by Elsevier B.V.