Nanometric light spots of cathode luminescence in Y_2O_3:Eu^3+ phosphor thin films excited by focused electron beams as ultra-small illumination source for high-resolution optical microscope

Abstract

We present an Electron-beam-eXcitation-Assisted (EXA) optical microscope with a nanometric illumination light source consisting of red cathode luminescence (CL) lights emitted by a Y2O3:Eu3+ phosphor thin film excited by a high-energy focused electron beams. Phosphor films a few hundred nanometers thick were fabricated on 50-nm Si3N4 membranes using electron beam evaporation. The film preparation conditions for brighter CL emissions were examined in terms of the post-annealing temperatures and film thickness. We succeeded in spatially resolving gold nanoparticles with average diameter of 100 nm. The observations proved that the microscope has a spatial resolution higher than the diffraction limits.