The influence of local SiC bonding density on the photoluminescence of Si-QDs upon thermal annealing the hydrogenated amorphous Si-rich silicon carbide thin films

Non-stoichiometric hydrogenated amorphous silicon carbide thin films (α-SiC:H) were deposited by plasma-enhanced chemical vapor deposition. The samples were subsequently post-annealed at 750, 900, 1050, and 1200 °C, respectively. Photoluminescence (PL) was measured by fluorescence spectrometer at room temperature. Infrared absorption was carried out by Fourier transform infrared absorption. Chemical compositions were analyzed by X-ray photoelectron spectroscopy. The synthesis of silicon quantum dots (Si-QDs) was characterized by Raman scattering spectroscopy and directly by high-resolution transmission electron microscope. PL measurements revealed that there were complicatedly shifted sub-bands upon the thermal annealing temperature increase. The behaviors of these shifted sub-bands showed converse trends as that of the local SiC bonding densities. A possible influence for the PL by the evolvement of the local SiC bonding densities and the synthesis of Si-QDs in the α-SiC:H samples is supposed.