Analytical Study of Thermal Annealing Behaviour of Erbium Emission in   Er2O3-Sol-Gel Silica Films
  Room-temperature 1535-nm-band photoluminescence in ~126 nm silica films (6 at. % doping), produced by spin-coating an Er2O3 and tetraethylorthosilicate sol-gel formulation on silicon substrates, was studied as a function of vacuum furnace annealing (500 to 1050 degrees C). Emission is strongly enhanced for annealing near 850 degrees C, which is shown by modeling the temperature dependence as arising from thermally-activated removal of hydroxyl ions. Suitability of such a process for silicon-based applications is discussed. 
Sufian Abedrabbo, Bashar Lahlouh and Anthony Fiory
cond-mat.mtrl-sci physics.optics