Laser melting of photoluminescent (Y0.92EU0.08)(2)O-3 films

Fluorescent red-emitting (Y0.92Eu0.08)(2)O-3 films were deposited on sapphi re substrates by the metallorganic chemical vapor deposition technique. The films were weakly luminescent in the as-deposited condition. The as-deposi ted films were composed of nanocrystals embedded in columnar grains. A KrF laser with ultraviolet (lambda =248 nm) pulses at a fluence level between 0 .9 and 2.3 J/cm(2) was applied to different regions of the film. Increasing the energy fluence density initially increased the photoluminescence inten sity but decreased it at the highest level. Transmission and scanning elect ron microscopy verified that surface melting and ablation occurred at all f luence levels. Computational modeling of the laser melting and ablation pro cess predicted that a significant fraction of the film is removed by ablati on at the highest fluence levels, thereby decreasing the photoluminescence intensity of the films due to the significant amount of material removed. ( C) 2001 American Institute of Physics.