Advanced Photon Source

An Office of Science National User Facility

Detlef Diesing from University Duisburg-Essen presents XSD seminar

Detlef Diesing in ArgonneDr. Detlef Diesing from the University of Duisburg-Essen gave a special XSD presentation on November 6, 2012. In his talk entitled “Excited Charge Carriers in Nanostructures” he draw the similarities between his research and the SXSPM project. Photoexcited electrons are normally used to reveal information about the site where they were released. When released by monochromatic photons, the photoelectrons carry information about the energy of their bound state below the Fermi level when these electrons are detected in an electron spectrometer. Photo excited electrons traveling toward the bulk of the sample are normally lost due to scattering and energy loss processes. When the sample's thickness is in the range of the penetration depth of the light, excited carriers exist throughout the sample. These photoexcited carriers lead to a current, when the nanometer thick metal sample is mounted on a metal-insulator sandwich. This current can be used to study the transport processes across Larry Pai Volker Rose Detlef Diesing in Argonnemetal layers as well as transport over and through potential barriers. Backup information can be collected when excited electrons are injected into the metal nanofilm by an STM tip. By changing the voltage at the STM tip one can inject an electron beam of adjustable mean energy into the metal nanofilm. A fraction of the electron beam can travel through or over the underlying potential barrier. A simulation of the electrons transport leads to detailed information about the structure of potential barriers.