The effect of aluminium on the post-anneal concentration of ion implanted bismuth in silica thin films

Abstract

We present a study of bismuth and aluminium co-implanted silica thin films and the effectiveness of post implantation annealing at activating Bismuth related photoluminescence. The only emission seen in photoluminescence from any of the samples was centred at 1160nm and is of the kind generally reported as due to silicon dislocation loops. In particular, the layers did not exhibit the broad NIR emission in photoluminescence as reported by other authors in Bismuth doped silica fibres. In order to study the retention of the Bismuth in the layers after annealing Rutherford Backscattering measurements were conducted on the samples, these found that the concentration of bismuth in the samples was greatly reduced following the annealing process when compared to the concentration implanted and explains why we measured no emission from bismuth. The concentration of bismuth remaining in the sample post anneal depended on the initial implant doses of bismuth and aluminium. We propose that aluminium plays the role of increasing the solubility of bismuth in oxide but that this was not sufficient in our samples to observe the photoemission reported for fibre materials.