Plasma Enhanced Chemical Vapor Deposited (Pecvd) Silicon-Rich-Nitride Thin Films For Improving Silicon Solar Cells Efficiency

Silicon-rich-nitride (SRN) films were deposited by plasma enhanced chemical vapour deposition (PECVD) by changing the silane and ammonia flow rates. These films were thermally annealed for precipitation of silicon nanocrystals. Measurements of refractive indices and FTIR absorption spectra of these films indicated increase in the silicon content. Thermally annealed SRN films exhibited photoluminescence in visible region indicating their potential as down-conversion layer for efficiency improvement in solar cells. A significant relative improvement in conversion efficiency using SiO_x/SRN layers in solar cells has been reported in our earlier work. In this paper, we present detailed synthesis process, characterization and analysis of SiN films. Characterization results and solar cell measurements indicate that the observed photoluminescence at 577nm in visible range in selected films along is responsible for improvement in conversion efficiency through down-conversion of high energy solar photons.