Optical absorption and luminescence properties of wide-band gap amorphous silicon based alloys

Optical measurements of hydrogenated amorphous silicon nitride and silicon carbide alloys are performed and analyzed to correlate the absorption and emission properties. We found that for a-Si _1−xN _x:H (0< x<0.52) and a-Si _1−xC _x:H (0< x <0.5) samples the photoluminescence (PL) spectra and the carrier lifetime distributions depend on the localized tail states as measured by photothermal deflection spectroscopy (PDS). These data support the static disorder model. For C-rich alloys (0.5< x<1) the radiative properties do not fit the model predictions due to the presence of C clusters.