Optical and Structural Properties of Europium-Doped Silicon Oxide Fabricated Using Integrated Sputtering and Chemical Vapour Deposition

Europium (Eu) doped silicon oxide (SiOx) thin films containing Eu concentrations of 0.2 to 6.4 at% were fabricated using a hybrid deposition system combining a magnetron sputtering gun serving as the doping source with electron cyclotron resonance plasma enhanced chemical vapour deposition (ECR-PECVD). The influence of annealing conditions on the structural and luminescence properties was thoroughly studied. The optical properties of the films were investigated by performing variable angle spectroscopic ellipsometry (VASE) and photoluminescence (PL) measurements. The Eu-related emission was found to be highly dependent on the deposition parameters and annealing conditions. Eu2+ and Eu3+ emissions, which are attributed to blue and red light emissions, respectively, were observed. The structural properties were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses, and the formation of nanoclusters was confirmed. At annealing temperatures of 900 °C and beyond, EuxSiyOz crystals were formed, and Eu ions were optically activated. As the light emissions of these thin films are in the blue and red wavelength range, they are promising candidates to be used as greenhouse covers and transparent solar cells.