Poster: http://www.physics.uwo.ca/colloquia/Colloquia%20Notices/2011_2012/GONCHAROVA%20Colloquium.pdf
Western University
DEPARTMENT OF PHYSICS AND ASTRONOMY
PHYSICS & ASTRONOMY COLLOQUIUM
Date: Thursday, 1st March 2012
Time: 1:30 p.m.
Location: Physics & Astronomy Seminar Room 22
Dr. Lyudmila Goncharova
Department of Physics & Astronomy
Western University
“Ion beam analysis in modern materials science”
ABSTRACT
Modern synthetic approaches and nanofabrication are providing us the means of creating material structures controlled at the atomic scale. Familiar examples include the formation of hetero-structures grown with atomic precision, nanoparticles with designed electronic properties, and new carbon-based devices. The forefront of such materials research includes creation of novel materials for energy and electronics applications. One of the challenges here is that electron transport properties of these diverse materials are closely linked to the basic interactions at the interface.
Ion scattering has been very successfully applied in our group to study interfaces of devices based on silicon and higher-mobility semiconductors, as well as to prepare arrays of nanocrystals for photonic applications. Among quantum emitters semiconductor quantum dots (QD) have the highest emission rates and can be easily integrated with semiconductor technology. QD emission properties often degrade because of various imperfections at the QD-dielectric interface. I will review the electronic states and optical properties of Si and Ge quantum dots with variable size prepared by ion implantation in a dielectric matrix studied by ion beam analysis and complementary techniques. Our results for QDs will be compared with other studies for Si-QDs prepared by alternative methods, and discrepancies in the interfacial compositions will be analyzed.
Finally, ion beam analysis, and its role in interfacial characterization will be described in the context of a number of projects underway in our group. These include: 1) interfacial analysis of complex oxide thin film stacks, 2) diffusion and oxidation processes with sub-nm resolution, 3) origin of ferromagnetic contribution to the magnetization of commercial single crystal substrates and thin films. Their understanding requires detailed analysis by high-resolution methods including ion beam analysis..
Coffee & cookies will be available, courtesy of PASA
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