High electric field electroluminescence in hydrogenated amorphous silicon carbide alloys

High electric field effects in hydrogenated amorphous silicon carbide alloys have been investigated employing a double insulating ac-driven electroluminescent device structure. The carbon content was systematically changed by deposition conditions. Two distinguished high electric fields effects, namely, hot-electron induced electroluminescence tailing into above-gap spectral domain and avalanche multiplication indicated from saturation of the electric field were found at the electric field strength of about 1.4-2.3 MV/cm in amorphous silicon carbide as the effects in hydrogenated amorphous silicon. From an analysis of the decay of the emission spectrum in terms of the lucky-drift model, the electron mean free path can be estimated; the mean free path tends to be reduced with an increase of the optical energy gap, which implies it would be reduced with an increase of structural disorder due to carbon alloying as in lower electric field.