March 21, 2012 Wednesday 15:30
Oğuzhan Gürlü, Istanbul Technical University
Novelties at age-old surfaces

Abstract:Application of the scanning probe microscopes to age old problems turned out to be both scientifically and technologically very fruitful in the past 25 years. Although many materials and their combinations have been extensively studied using integral methods like diffraction and spectroscopy techniques, novel information by means of scanning probes revealed some amazing properties.

For instance Pt-Ge system is a well-studied material system. However, when looked at the atomic level it was seen that Pt atoms adsorbed onto Ge(001) surface form extremely well-ordered nanowire arrays by self-organization after high-temperature annealing. Using scanning tunneling spectroscopy/microscopy, it is shown that they are metallic and defect free. They are only 0.4 nm thick with a spacing of 1.6 nm in between, and have aspect ratios up to 1000. Their formation can be discussed in terms of a relativistic property possessed by heaviest 5d elements, and the pathway to their formation can be explained by dimer breakup on Ge(001) surface at elevated temperatures followed by a surface polymerization reaction. The possibility of controlled local manipulation of the self-organized Pt nanowires on Ge( 001) surfaces, at room temperature, has also been explored. These nanowires are composed of Pt dimers, which are found to be rather weakly bound to the underlying substrate. Using this property, the possibility of carrying the constituting dimers of the Pt nanowires from point to point with atomic precision at room temperature was investigated.

The study of surfaces at the nanometer scale with atomic precision requires a tremendous amount of effort for the preparation of the essential infrastructure. By the end of this talk, our efforts for the preparation of these facilities at Istanbul Technical University will be shown and several preliminary results of some of our other studies on various surface/interface systems will be discussed.

CV:

Under Grad: Bilkent University Physics Dept. (1994-1999)
Grad (Ms-PhD): University of Twente, The Netherlands (1999-2004)
Post.Doc: Max Planck Institute for Solid State Research, Stuttgart, Germany (2004-2007)
Asst. Prof.: İstanbul Technical University, Physics Dept. (2007-)
Advisor to the Rector at İTÜnano-Project for the installation the new Clean Room facilities.
Research Interests: Morphological and electronic properties of metal, semiconductor and heteroepitaxial surface/interface systems at the nano scale, Development of Scanning Probe Techniques, Production of novel crystal systems.