Alkaline Earth versus Noble Metal Particles on MgO Thin Films: Growth and Optical Properties

作者:Myrach Philipp; Nilius Niklas*; Freund Hans Joachim
来源:Journal of Physical Chemistry C, 2009, 113(43): 18740-18745.
DOI:10.1021/jp904174c

摘要

Nucleation and growth of Mg, Ca, and Au particles on 8 ML thick MgO/Mo(001) films have been investigated by scanning tunneling microscopy (STM). Whereas the alkaline earth metals strongly interact with the MgO surface and form islands that are in registry with the square oxide lattice, a reduced coupling is suggested for Au on the basis of the observed hexagonal particle shapes. Optical properties of the metal particles are probed by injecting electrons from the STM tip into individual deposits and detecting the resulting photon emission. The overall spectral shape is governed by a, plasmon-mediated photon emission that is characteristic for the different particle materials. However, a distinct fine-structure that is superimposed on the plasmon response is found to be independent of the chemical identity and geometry of the particles. This spectral contribution is assigned to the discrete excitation behavior of particle plasmons via inelastic electron transport through the double-barrier STM junction.

  • 出版日期2009-10-29