Intrinsic Sub-Nanocrystalline Silicon Thin Films: Active Layer for Solar Cells

The study presents the typical aspects of silicon thin films in terms of growth under variation of applied power using Radio frequency Plasma Enhanced Chemical Vapor Deposition technique (RF-PECVD). The corresponding material found to maintain the typical properties of amorphous nature without compensating the structural modification in terms of crystallinity and has been defined as a material having the “sub-nanocrystalline phase”. Characterizations like, UV-Visible spectroscopy, Photoluminescence and Temperature dependent conductivity was used to effectively map the structural details along with electrical and optical properties. The optical bandgap of the films found to be vary from 1.77 eV to 1.99 eV with typical photoresponse variations in the range 103 to 101. At 30 W applied power, the transition regime observed with the formation of sub-nanocrystallites. The analysis of such phase reveals the superior optoelectronic properties. This article suggests the suitability of sub-nanocrystalline silicon thin films to replace hydrogenated amorphous silicon in various applications.