Structural and optical properties of a-Si1−xCx:H grown by plasma enhanced CVD

Abstract In this work, we discuss on the physical properties of hydrogenated amorphous silicon carbide (a-Si 1− x C x :H) thin films deposited by plasma enhanced CVD by using SiH 4 +CH 4 and SiH 4 +C 2 H 2 gas mixtures under several deposition conditions. We can argue a complete chemical order in the samples deposited by SiH 4 +CH 4 for x >0.4, while for those grown by SiH 4 +C 2 H 2 , such order is preserved for lower C content. With regards to the radiative properties, for all the under-stoichiometric samples the photoluminescence (PL) Stokes shifts result to be strictly correlated to the absorption properties within the static disorder model. For C-rich materials, the electronic density of states becomes much more complex than in Si-rich ones because of the possibility of sp 2 and sp 3 configurations for C bonds, so that the presence of localized tail states cannot explain anymore the PL properties.