Optical Spectroscopy and Scanning Tunneling Microscopy Studies of Molecular Adsorbates and Anisotropic Ultrathin Films

Technical Report · Sat Jun 01 04:00:00 EDT 2019

DOI:https://doi.org/10.2172/1542895· OSTI ID:1542895

Hemminger, John C. ^[1]

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1. University of California, Irvine, CA (United States); Department of Chemistry, University of California, Irvine

The goal of the research under this project was to develop sufficient fundamental understanding to allowthe controlled preparation of nano-, and meso-structured surfaces with novel optical propertiesand chemical reactivity. The research placed an emphasis on the synthesis of, sometimes complex, surface structures under conditions that allow for detailed control and understanding of the composition and structure and the subsequent relationship to properties and chemical reactivity. In this research we utilized a combination of optical probes (Polarization and angle dependent laser reflectivity and Laser Raman Scattering) with modern surface imaging experiments (electron microscopy (SEM, TEM), and variable temperature ultra high vacuum scanning tunneling microscopy (STM)). These experiments were combined with conventional methods of UHV surface science (High Resolution Electron Energy Loss Vibrational Spectroscopy (HREELS), Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS) and thermal desorption spectroscopy (TDS)). The conventional surface probes provide well-tested methods for the preparation and characterization of substrates. The optical probes used provided powerful methods for the characterization of the structure dependent optical properties of novel molecular and nanometer scale, and mesoscale surface structures as well as molecular identification and quantification of adsorbates in monolayers and ultrathin films. A combination of STM and SEM/TEM were utilized to study the growth of mesoscopically ordered nanometer sized metal and metal oxide structures on well-defined substrates such as highly ordered pyrolytic graphite (HOPG). We developed methods (e.g.photoelectrochemical deposition) to decorate nanometer scale metal oxide structures with transition metal nanoparticles generating Nanoparticles on Nanoscale substrate materials (NpNs). The electronic structure and chemical properties of these new structures were studied and contrasted with those of the more conventional nanoparticles on macroscopic substrate materials.

• Research Organization: University of California, Irvine, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
• DOE Contract Number: FG02-96ER45576
• OSTI ID: 1542895
• Report Number(s): DOE-UCI--45576
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
model catalysts
nanostructured surfaces