Visible Luminescent Activation of Amorphous AlN:Eu Thin-Film Phosphors with Oxygen

We have investigated the effects of oxygen incorporation on cathodoluminescence (CL) and photoluminescence (PL) from sputtered amorphous films of AlN:Eu 3+ . Ordinarily, these materials must be activated at elevated temperatures (~1000K) before appreciable luminescence can be observed. We have shown that oxygen doping is an effective alternative to thermal activation. Studies of CL intensity versus oxygen contamination indicate that luminescence turns on if the oxygen content of the sputtering plasma exceeds a few percent. Significantly, oxygen appears to have a greater impact (>600-fold) on luminescence than does thermal activation (100-fold). The oxygen dependence of PL intensity varies slightly from that of CL intensity. A possible explanation for this observation is proposed. The results suggest that low temperature alternatives to the customary thermal activation process may be available. Such alternatives would eliminate materials constraints and would permit the facile integration of plastic components or substrates with rare-earth-doped III-N luminescent devices.