Project title:

Effect of reduced lateral dimensions on the optical and magnetic properties of dilute magnetic and antiferromagnetics nanowires

 

Contact:

Prof. Dr. Michael Fröba

Universität Hamburg
Fachbereich Chemie
Institut für Anorganische u. Angewandte Chemie
Martin-Luther-King-Platz 6
20146 Hamburg

Phone: +49 (0) 40 428 38 3137
Fax: +49 (0) 40 428 38 6348

 

Prof. Dr. Peter J. Klar

Justus-Liebig-University of Giessen
Institute of Experimental Physics I
Heinrich-Puff-Ring 16
D-35392 Giessen, Germany

Phone: +49 (0) 641 9933190
Fax: +49 (0) 641 9933139

 

Prof. Dr. habil. Wolfram Heimbrodt

Department of Physics and Material Sciences Center,
Philipps-University Marburg
Renthof 5
35032 Marburg

Phone: +49 6421 28 21353
Fax: +49 6421 28 27036

Abstract:

It is the aim of the project to study the changes of the optical properties of semiconductor anostructures such as nanowires or chain-like arrangements of quantum dots as a function of lateral diameter. Many processes in semiconductors such as energy-transfer processes, spin- transfer processes, and carrier-relaxation processes will be modified with respect to bulk semiconductors in wire-like nanostructures because of the geometric restrictions. In semiconductor structures these effects are usually reflected in the luminescence dynamics. Examples are inter-dot excitation-transfer in a chain-like arrangement of quantum dots or excitation-transfer between transition-metal impurities in II-VI nanowires. A change of such processes occurs when the characteristic length scale of the problem is larger than the diameter of the wire or chain-like arrangement. The characteristic length scales involved strongly depend on the type of process and can vary considerably between a few tens of nanometers and several hundred nanomenters. The DFG priority program "Nanowires and Nanotubes: From Controlled Synthesis to Functions" is an ideal platform for such studies as the different research groups involved provide a large variety of semiconductor-based wire- like structures with suitable luminescence properties. A major part of the samples used in this project, i.e. Mn-doped II-VI nanowires with diameters below 10 nm, will be synthesized in project part A (Fröba / Gießen). Further samples will be provided by cooperations within the priority program, i.e. II-VI and III-V quantum dots in polymer wires with diameters below 100 nm (Greiner, Wendorff / Marburg ; Schlecht / Berlin) and transition-metal and rare-earth doped ZnS and ZnO wires with diameters ranging from several 10 nm to 1 μm. The optical measurements on nano- and pico-second time scales as well as the corresponding analysis will be performed in project part B (Klar, Heimbrodt / Marburg).