Environment of Er in a-Si : H: Co-sputtering versus ion implantation

We report a comparative Extended X-Ray Fine Structure (EXAFS) study of Er i n a-Si:H prepared by Er implantation in a-Si:H and by co-sputtering undergo ing the same cumulative annealing processes. It mas found that the Er envir onment in as-implanted samples is formed by Si atoms, which are replaced by oxygen under annealing. In the co-sputtered samples, the initial low coord ination oxygen environment evolves under thermal treatment to an Er2O3-like neighborhood.