Dr. Alberto Herrera-Gomez 

http://qro.cinvestav.mx/~aherrera/web/  aherrerag@cinvestav.mx

  • Professor of Materials Science. CINVESTAV-México (1994-to date).
  • Fellow of the American Vacuum Society “For his seminal contributions to developing quantitative surface analysis, especially for XPS” (2016).
  • Group leader, within the International Standardization Organization (ISO/TC201:SC7), for the development of a standard about the determination of the background in XPS data.
  • First Vice Chairman of the E42 Committee (Surface Analysis) of the ASTM (2009-to date).
  • Chairman (“Technical Contact”) of subcommittees for the revision of standards related to XPS (background, charge reference).
  • Chairman of the surface analysis Terminology Subcommittee (2008-to date).
  • Member of the Advisory Board of the Surface and Interface Analysis journal (2015 to date).
  • Secretary of the Applied Surface Science Division (2010-2013) of the International Union for Vacuum Science and Technology (IUVSTA).
  • Member at Large of the Applied Surface Science Division of the American Vacuum Society (2007-2011).
  • “Daniel Schechtman” Chair. Universidad Autónoma Metropolitana (2012-2013).
  • President of the Mexican Vacuum Society (2002-2004).
  • Visiting Professor, University of Texas at Dallas (2005-2007).
  • 90+ papers, 1000+ citations, H-index 14. Graduate students: 10 Ph.D, 12 M.S., 1 B.D.

Education:

  • Posdoctorate. Electrical Engineering, Stanford University, 1994.
  • Ph.D. Applied Physics. Stanford University, 1994.
  • M.S. Applied Physics. Stanford University, 1991.
  • M.S Physics. CINVESTAV, 1988.
  • Bachelor in Physics. Universidad Autónoma Metropolitana, 1985.

Current Main Research Topics:

  • Transition metal oxides.
  • Background signal in XPS data.
  • Mass transport in multilayered nanofilms.

Oct. 15, 2017
10:00~12:00; 13:00~15:00

Basic Principles of XPS and Peak-Analysis (Fitting) of Real-Data

The concepts of the photoemission phenomenon are described. The course is theoretical-practical. The basic aspects of XPS-data peak-fitting are covered by working with real data.  The origin of the chemical shift is described through fitting multicomponent spectra employing various singlet peaks.  The combination of symmetric and asymmetric line shapes is exemplified employing C 1s spectra of graphene mixed with other types of carbon.  The use of doublets is described with simple core levels such as Au 4f, Ag 3d, and Si 2p, as well as with more complex spectra requiring asymmetric shapes (such as Cr 2p and Fe 2p).  The background options (Shirley, Tougaard, lineal, etc.) are described with specific examples where it is appropriate to employ each one.  The combined use of them is also described in detail.  Robust methods for resolving overlapping peaks are also discussed employing ARXPS data.

The attendees are welcome to bring their own data to be used as additional examples. This is an important part of the course since it allows for the attendees to experience in real-time the difficulties associated to peak fitting. The software AAnalyzer is employed. It is expected that the attendee will be able to perform high-quality fits, with physical fundamentals, at the end of the course.

The bibliography can be reduced to “Practical Methods for Background Subtraction in Photoemission Spectra.” A. Herrera-Gomez et al.  Surf. Interface Anal. 2014, 46, 897–905, and the information in http://rdataa.com/aanalyzer/aanaWhy.htm.