Published online by Cambridge University Press: 17 March 2011
The Er local environment of a-Si:H<Er> prepared by PECVD using a metalorganic precursor was determined by EXAFS. We found that in as-deposited samples Er is coordinated to 6 oxygen atoms at 2.28±0.01Å, very similar to Er2O3. Annealing at 420°C hardly affects the Er neighborhood, but higher annealing temperatures (starting at 600°C up to 1033°C) decrease the Er-O separation as much as 0.05Å, maintaining the Er average coordination around 6. This is interpreted as due to the formation of a carbon second neighbor shell. Our results show that the Er local environment is not related with the luminescence enhancement for annealing at moderate temperatures.