Optical properties of porous nanostructured Y2O3:Eu thin films

Abstract

Nanostructured photoluminescent thin films of europium-doped yttrium oxide (Y2O3:Eu), a well-known luminescent material, were grown using electron-beam evaporation in combination with the glancing-angle deposition technique. GLAD makes use of controlled substrate motion during extremely oblique physical vapor deposition of a thin film resulting in a high degree of control over the nanostructure of the film. Scanning electron microscopy and x-ray diffraction were used to characterize film nanostructure, while the light emission properties of these films were characterized by photoluminescence measurements. Transmission ellipsometry measurements were used to determine the degree of selective transmission of polarized light through the samples. The polarization of the emission from chevronic and helical films was determined through the measurement of the Stokes parameters of the emitted light for each sample. Comparison of the degree of polarization during the emission experiments to the degree of selective transmission during the transmission experiments, as well as comparison of the sense of the polarization of the output light in each case, showed that a filtering effect related to the nanostructural morphology was likely the source of the polarization of the output light in both cases.