Er-doped amorphous Al2O3 films produced by alternate pulsed laser deposition show a weak Er PL emission at around 1.54 μm, the lifetime being of the order of 0.1 ms. On thermal annealing treatments up to 850°C, the intensity increases and lifetimes as high as 6 ms are achieved. Above 800°C slight changes in the shape of the 1.54 μm emission band are observed, suggesting changes in the local Er3+ environment. Electron irradiation of annealed films leads to a decrease in the PL intensity without changing the lifetime. This effect, which anneals out between 200°C and 600°C, is most likely due to electronic processes involving Er ions. This type of defect is not present in as-grown films.