Precipitate coarsening and self organization in erbium-doped silica

The influence of heat treatment at and above $1100\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ on thin erbium-rich silica layers embedded in silica has been studied experimentally by secondary ion-mass spectrometry and cross-sectional transmission electron microscopy. Redistribution of erbium atoms is observed at these temperatures, and formation of erbium-rich precipitates is seen to occur if the erbium concentration exceeds $\ensuremath{\sim}0.01$ at. %. These precipitates are observed to coarsen and subsequently dissolve with increasing annealing time. Moreover, self organization of precipitates has been observed in the form of layering of the precipitate ensemble.