Speaker: Dr. Oguzhan Gurlu, Max Planck Institute for Solid State Research,
	 Nano-scale Science Department, Stuttgart, Germany 

Title: Through the seeing needle: "Scanning Tunneling Microscopy and
       Spectroscopy on Metal/Semiconductor Surfaces"


Date: Fri 28 April, 2006
Time: 15:45
Place: Science Building, Room Z42

Abstract:

Although young, Scanning Tunneling Microscopy (STM) is one of the most
powerful techniques of surface science. The inherent atomic resolution
offered by this technique makes it unequivocally the real tool of
nano-science, along with several others that stemmed from STM (like
AFM, SNOM, etc). Moreover, with the introduction of Scanning Tunneling
Spectroscopy (STS), it became possible to perform spectroscopic
measurements on nano-structures with sub-nanometer resolution, which
was lacked by the conventional tools of spectroscopy. Consequently,
this technique constitutes an important part in the beginning of a new
era with concepts like artificial atomic structures, quantum mirages,
one dimensional magnetism, molecular electronics, etc.

Using STM and STS, we investigate the morphological and electronic
properties of clean semiconductor and metal surfaces, metal
nano-structures, ultra-thin insulating films and molecular systems
grown on metal surfaces. In the first part of this talk STM and STS
studies performed on clean Si(001) and Ge(001) surfaces will be
focused on. The unique opportunity to observe a local metallic surface
state with STS will be exemplified on Ge(001) surface. Next, the
formation of Pt atomic chains on Ge(001) surfaces will be shown
illustrating our metallic thin film growth studies on semiconductor
surfaces. Following the discussion over semiconductor and
metal-on-semiconductor systems, the STM and STS studies on the growth
of ultra-thin insulating layers on metal surfaces will be
addressed. The atomic modeling of mono and bi layers of KCl films on
Cu surfaces will be presented along with the band gap measurement of
these films. The talk will be concluded with the presentation of the
application of STM to molecular systems and nano-photonics.



Please visit http://home.ku.edu.tr/~sci-math for a schedule of
upcoming Science -Math seminars at Koc University.