Improvement of luminescent properties of thin-film phosphors by excimer laser processing

摘要

Thin-films of europium doped yttrium oxide, Y(sub 1)(minus)x)Eu(sub x))(sub 2)O(sub 3), were deposited on sapphire substrates by metallorganic chemical vapor deposition. The films, (approximately) 400 nm thick, were weakly luminescent in the as-deposited condition. A KrF laser was pulsed once on the surface of the films at a fluence level between 0.9--2.3 J/cm(sup 2). One pulse was sufficient to melt the film, which increased the photoluminescent emission intensity. Melting of a rough surface resulted in smoothing of the surface. The highest energy pulse resulted in a decrease in luminous intensity, presumably due to material removal. Computational modeling of the laser melting and ablation process predicted that a significant fraction of the film is removed by ablation at the highest fluence levels.