The effect of annealing conditions on the crystallization of Er-Si-O formed by solid phase reaction

The sol-gel method was used to prepare the amorphous preform. The samples were then annealed at 1250 °C in Ar for the solid phase growth of Er-Si-O crystals. The obtained Er-Si-O crystals showed, however, some different types of XRD patterns and the PL spectra. It was speculated that a slight amount of residual oxygen in the annealing furnace affected the Er-Si-O crystal structure. To study the effect of oxygen, during solid phase growth three processes were applied; putting a Si cap on the sample to reduce the influence of the atmosphere, additionally putting a carbon sheet as oxygen getter on the sample covered with a Si cap and no Si capping. Three kinds of XRD patterns, PL spectrum fine structures, PLE spectra and PL time decays were observed, depending on the three processes. These results indicate that the fine arrangements of Er-Si-O crystals are affected by oxygen content in the crystal which is very sensitive to oxygen in the annealing Ar atmosphere during the solid phase growth and their properties are come from their particular crystalline structures.