Surface, Adatom and Nanostructure Electronic Properties Measured by Low Energy Ion-Surface Charge Exchange

Featuring Jory A. Yarmoff, Ph.D.
Professor, Department of Physics and Astronomy
University of California, Riverside

Location:  Donald Bren Hall,  Room 1300
Free and open to the public

Abstract:
Low energy ion scattering (0.5-5 keV) is a popular surface analysis technique that has traditionally been used to obtain compositional and structural information about the surface of a material at the atomic scale.  Recent work has hown that charge exchange during the scattering of low energy alkali ions from solids can also provide a unique probe of surface electronic properties.  The sensitivity results from electrons that resonantly tunnel between the projectile ionization level and overlapping states in the material.  The talk will use numerous examples to illustrate the basic physics of the process and demonstrate the variety of problems that can be addressed.  These include mapping out inhomogeneous potentials at the surfaces of oxide materials and in the presence of adsorbates, as well as measuring the presence of quantum states in nanomaterials.  Nanomaterials were produced for these experiments by deposition, sputtering of thin metal films and by buffer layer assisted growth (BLAG).  In addition, the  use of novel projectiles, such as Si, P or Ga ions, increases the sensitivity to different regions of the electronic structure.