Imaging and Spectroscopy of the Au Nanoclusters in the YSZ Films by Ballistic Electron/Hole Emission Microscopy

D.O. Filatov, D.V. Guseinov, I.A. Antonov, O.N. Gorshkov, A.I. Bobrov, D.A. Pavlov
N.I.Lobachevskii University of Nizhny Novgorod, RU

Keywords: ballistic electron emission microscopy, nanoclusters, dielectric films, imaging, specroscopy

Summary:

We report on the first time application of Ballistic Electron/Hole Emission Microscopy (BEEM/BHEM) to imaging and spectroscopy of metal NCs in the ultrathin dielectric films. We studied the yttria stabilized zirconia (YSZ) films (12% mol. Y) with Au NCs on Si prepared by Magnetron Sputtering and annealing. Such films are promising for the resistive switching non-volatile memory applications. Cross-sectional High Resolution Transmission Electron Microscopy revealed nearly spherical Au NCs of 1.5 to 3.5 nm in diameter arranged in a single sheet between YSZ layers. The BEEM images demonstrated the spots of increased collector current of 1 to 2.5 nm in size related to the ballistic electron tunneling via the Au NCs. BEEM/BHEM spectra of the NCs demonstrated the stepwise features attributed to the quantum confined states in the Au NCs. The estimate of the NC diameter by the best fit between the quantum confined state energies determined from the BEEM/BHEM spectra and the ones calculated for a spherical quantum dot yielded 3 to 4 nm that is consistent with the TEM data. The results of present study demonstrate the capabilities of BEEM/BHEM in characterization of the ultrathin dielectric films with metal NCs in both research and production.