Revealing the nano-structures of low-dimensional germanium on Ag(1 1 0) using XPS and XPD

Abstract

In this work, we present a structural investigation of sub-monolayer films of germanium on Ag(1 1 0) by means of photoelectron spectroscopy (XPS) and diffraction (XPD), as well as low-energy electron diffraction (LEED). Since the rising progress in the synthesis of various kinds of nanoribbons, also germanium nanoribbons (Ge-NR) have been synthesized on Ag(1 1 0), recently. Here, we focus on their structural evolution and found the formation of two different phases of germanium at coverages of $${0.5}\, \hbox {ML}$$ 0.5 ML and $${0.7}\,\hbox {ML}$$ 0.7 ML , differing fundamentally from predicted nanoribbon structures. By means of LEED measurements, we obtained evidence for germanium superstructures which are not aligned along the $$[{\overline{1}}\;1\;0]$$ [ 1 ¯ 1 0 ] -direction, as expected for nanoribbon growth. Using synchrotron-based high-resolution XPS and XPD experiments of the Ge 3d and Ag 3d core-levels, we resolved the local chemical and atomic order of the germanium films. Thus, the strong internal bonding of the buckled germanium film and a weak Van-der-Waals interaction between silver and germanium were discovered. Moreover, XPD-simulations delivered a detailed model of the structural arrangement of the preliminary nanoribbon phase, which also provided an approach to identify the origin of the two chemically shifted components in the Ge 3d signal by applying a component-wise decomposition of the XPD data.

Facile synthesis of ultrafine Cu, Ag, and Ni nanoparticles supported on 3D hydrogel beads for the rapid reduction of 4-nitrophenol

“…5b, the high-resolution spectrum of Ag 3d in Ag/GLA-PEI/Ca-SA beads includes two peaks at 365.1 and 371.3 eV, which are assigned to Ag 3d 5/2 and Ag 3d 3/2 peaks of metallic Ag [36]. Generally, the difference between the peak positions of the two peaks is 6 eV, which indicates the existence of Ag nanoparticles [40]. Figure 5c shows the high-resolution XPS spectra of the Cu/GLA-PEI/Ca-SA beads, in which two peaks are observed at 930.2 and 950.…”