Temperature stable Au nanoparticles embedded in Er3 + doped ZrO2 sol–gel thin films prepared by spin coating

Gold nanoparticles (NP) were successfully embedded as single and triple stacks into Er3 + doped spin-coated sol–gel ZrO2 thin films. The effect of different initial Au NP solution concentrations and annealing temperatures on the stack structure has been investigated. The NP coverage was varied by the concentration of the applied NP solution from sub-monolayers to structured networks. Furthermore, the coverage depends on the surface quality, as confirmed by atomic force microscopy (AFM). The existence and characteristics of the embedded Au NPs after annealing up to 1000 °C were investigated by UV–Vis spectroscopy and transmission electron microscopy (TEM). Finally, X-ray diffraction (XRD) measurements were used to correlate the annealing temperature with the resulting crystal structure of the ZrO2:Er3 + films.