Anomalous temperature dependence of photoluminescence from a-C:H film deposited by energetic hydrocarbon ion beam

The temperature dependence of photoluminescence (PL) from a-C:H film deposited by CH3+ ion beam has been performed and an anomalous behavior has been reported. A transition temperature at which the PL intensity, peak position and full width at the half maximum change sharply was observed. It is proposed that different structure units, at least three, are responsible for such behavior. Above the transition point, increasing temperature will lead to the dominance of non-radiative recombination process, which quenches the PL overall and preferentially the red part. Possible emission mechanisms have been discussed.