Room-temperature formation of erbium-related luminescent centers in anodic alumina

Luminescent Er-doped Al2O3 films have been fabricated at room temperature by a technique including magnetron deposition of Er-doped Al film on a silicon substrate and its subsequent electrochemical anodization. The films demonstrate strong Er-related photoluminescence at about 1.53 mu m as recorded in the temperature range of 4.2-300 K. The effect is not influenced by annealing of the samples up to 200 degrees C. Upon annealing at 300-500 degrees C the luminescence intensity decreases, while above 600 degrees C it starts to recover. Annealing at 1000 degrees C restores the photoluminescence spectra to the initial level. The annealing peculiarities observed have been explained by dominant hydrogen outdiffusion at 300-500 degrees C, rearrangement of point defects at 600-800 degrees C, and recrystallization processes above 850 degrees C in the alumina film. Activation energies of these processes have been estimated to be 0.76 eV (for parabolic rate), 0.58 eV (for linear rate), and 0.46 eV (for linear rate), respectively. (C) 1998 American Institute of Physics. [S0003-6951(98)04942-0].