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Email: israel.bar-joseph@weizmann.ac.il
 Title:
Professor  Tel: +972-8-934-4534
 Fax: +972-8-934-4477
 Building: Braun
 Room: L2
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Research Interests:
Modern crystal growth techniques make it possible to grow pure semiconductor structures in a very controlled manner. The atoms are deposited layer by layer, so that an almost perfect lattice is obtained. Using this method we can tailor the potential inside the crystal and form potential barriers and wells. A particularly interesting structure, which can be formed in this manner, is a quantum well: a narrow region between two potential barriers. It acts as a trap for electrons and restricts their free motion to two dimensions.
The understanding of the electrons behavior and interactions in this two-dimensional system is the focus of our research, and we do that using optical spectroscopy. Short pulse lasers allow us to study energy and spin relaxation processes with a 100 fs time resolution. We implement near-field scanning probe spectroscopy to measure the local emission spectrum, and thereby obtain the local properties of theelectron gas. Photo-luminescence measurements at high magnetic fields are used to determine collective electron states. These measurements are done at very low temperatures close to the absolute zero, in order to suppress the effect of the thermal motion and to be able to resolve small energy excitations.