Physics Department

The University of Texas at Arlington

Solid State Seminar

___________________________________

 

Characterization of ZnO Single Crystals by Positron Annihilation

 

Dr. Gerhard Brauer

Institut fur lonenstrahlphysik und Materialforschung

 

2:00 pm Thursday August 31, 2006, Room 101 SH

 

Abstract

 

Positron Annihilation Spectroscopy (PAS), based on radioactive positron sources, is now a well-established tool for the study of electronic and defect properties of bulk solids, whereas mono-energetic positron beams are needed to investigate thin films and surfaces. As an introduction, the application and basic physics behind PAS methods will be explained briefly.

            Zinc oxide (ZnO) is a potential semiconductor suitable for fabrication of visible and UV light emitters and detectors as well as high-temperature electronics. However, to achieve this goal, a full understanding of the role of lattice defects is needed as they largely control the optical and electrical properties. Here, a summary of our recent research results to identify lattice defects in ZnO single crystals will be presented which includes the application of radioactive positron sources, a mono-energetic positron beam, and also theoretical calculations.

            Finally, an outlook about future work will be given. This includes the construction of an accelerator-based and pulsed intense positron beam, and the study of ZnO nanorods.

.

 

Refreshments will be served in the Physics Library at 1:30pm