Ben Taber was awarded the prestigious UO Dissertation Research Fellowship for the 2017-18 academic year. This fellowship is designed to support outstanding doctoral students and promote excellence in research at the University of Oregon by providing financial support for exceptional doctoral candidates to complete their dissertations.
For a list of this year’s graduate school award recipients, click here.
Nazin Lab undergraduate researcher William Crowley successfully defended his Honors College Thesis earlier today. His thesis, “Fabrication of Silver Scanning Tunneling Microscope Tips with Acetic Acid,” earned Distinction, an honor awarded to the top ten percent of graduates of University of Oregon’s Robert D. Clark Honors College.
Bravo, William!
The University of Oregon has awarded Dr. George V. Nazin tenure. Congratulations!
Ben Taber and Christian Gervasi will be attending the upcoming ACS National Meeting in San Francisco. Ben will be giving an oral presentation, “Scanning tunneling microscopy of alkyl-substituted oligothiophenes on Au(111): Real-space visualization of molecular electronic structure,” from 8:10-8:50 am on Sunday, April 2, in the Sutro room of Parc 55. Christian Gervasi will be presenting a poster, “Impact of surface reconstruction on the electronic structure of PbS QD nanocrystals: Experiment and theory,” during the Inorganic Division poster session from 5:30-7:30 PM on Tuesday, April 4 in Hall D of the Moscone Center.
Check out them and their work!
Chase Callahan, an undergraduate Chemistry major, has joined the Nazin Lab. Welcome!
Tomas Lee, an undergraduate Chemistry student at the University of Oregon, has joined the Nazin lab. Welcome!
Yesterday, Dmitry Kislitsyn successfully defended his dissertation, “Spectroscopic Studies of Nanomaterials with a Liquid-Helium-Free High-Stability Cryogenic Scanning Tunneling Microscope.” Dr. Kislitsyn has been instrumental in building and developing the Nazin Lab, and he will most certainly be missed. We wish him the best of luck as he goes to New York to begin his new position at Global Foundries!
The Nazin Lab welcomes three rotation students this quarter: Charlie Davis, Motoaki Honda, and Thomas Kasel!
Quantum confinement of two-dimensional surface electronic states is a possible avenue for the controllable modification of metal surface electronic structure. The Nazin Lab used scanning tunneling microscopy and spectroscopy (STM/STS) to study the electron confinement within individual ring-shaped cycloparaphenylene (CPP) molecules, prepared by Evan Darzi and Ramesh Jasti, that formed self-assembled films on Ag(111) and Au(111) surfaces. STM imaging and STS mapping revealed the presence of electronic states localized in the interiors of CPP rings, inconsistent with the expected localization of molecular electronic orbitals. Electronic energies of these states showed considerable variations correlated with the molecular shape. These observations are explained by the presence of localized states formed due to confinement of surface electrons by the CPP skeletal framework, which thus acts as a molecular electronic “corral”. These experiments suggest an approach to robust, large-area modification of the surface electronic structure via quantum confinement within molecules forming self-assembled layers.
Benjamen N. Taber, Christian F. Gervasi, Jon M. Mills, Dmitry A. Kislitsyn, Evan R. Darzi, William G. Crowley, Ramesh Jasti, and George V. Nazin published their results, “Quantum Confinement of Surface Electrons by Molecular Nanohoop Corrals”, in the Journal of Physical Chemistry Letters. The letter was published online on July 26, 2016, and is available at: http://pubs.acs.org/doi/abs/10.1021/acs.jpclett.6b01279.
Spatial mapping of the local density of states of a silicon nanocrystal after the creation of a dangling bond defect. From Fig. 3 of the main text.
The Nazin Lab recently published an investigation of silicon nanocrystal (SiNC) dangling bond (DB) defects, “Visualization and spectroscopy of defects induced by dehydrogenation in individual silicon nanocrystals,” in the Journal of Chemical Physics. In this communication, we use scanning tunneling spectroscopy (STS) to study the impact of dehydrogenation on the electronic structures of hydrogen-passivated silicon nanocrystals supported on the Au(111)surface. Gradual dehydrogenation results, initially, in reduction of the electronic bandgap, and eventually produces midgap electronic states. We also use theoretical calculations to show that the STS spectra of midgap states are consistent with the presence of silicon dangling bonds, which are found in different charge states. Our calculations also suggest that the observed initial reduction of the electronic bandgap is attributable to the SiNC surface reconstruction induced by conversion of surface dihydrides to monohydrides due to hydrogen desorption. Our results thus provide the first visualization of the SiNC electronic structure evolution induced by dehydrogenation and provide direct evidence for the existence of diverse dangling bond states on the SiNC surfaces. The article was published online June 28, 2016, and is available at: http://dx.doi.org/10.1063/1.4954833