Influence of defects on the photoluminescence of pulsed-laser deposited Er-doped amorphous Al2O3 films

Er-doped amorphous Al2O3 films produced by alternate pulsed laser depositio n show a weak Er PL emission at around 1.54 mu m, the lifetime being of the order of 0.1 ms. On thermal annealing treatments up to 850 degrees C, the intensity increases and lifetimes as high as 6 ms are achieved. Above 800 d egrees C slight changes in the shape of the 1.54 mu m emission band are obs erved, suggesting changes in the local Er3+ environment. Electron irradiati on of annealed films leads to a decrease in the PL intensity without changi ng the lifetime. This effect, which anneals out between 200 degrees C and 6 00 degrees C, is most likely due to electronic processes involving Er ions. This type of defect is not present in as-grown films. (C) 2000 Elsevier Sc ience B.V. All rights reserved.