| 日時: |
2010-03-26 15:30 - 16:30 |
| 場所: |
4号館2階輪講室１ |
| 会議名: |
物構研セミナー「Theoretical Study on Optical Spectra of Semiconductor Quantum Wires」 |
| 講演者: |
Professor Ping Huai (Shanghai Institute of Applied Physics , Chinese Academy of Sciences) |
| 講演言語: |
英語 |
| URL: |
http://pfwww.kek.jp/pf-seminar/ |
| アブストラクト: |
Low dimensional semiconductor lasers are believed to have better performance due to more concentrated density of states at the lowest energy. The dependence of optical spectra on the densities of electrons in a conduction band and holes in a valence band, which can be controlled by the excitation intensity, is of special importance for understanding lasing and nonlinear optical processes.
We have conducted systematic studies on the optical properties of semiconductor quantum wires by using theoretical model calculation. The optical spectra of semiconductor quantum wires have been first theoretically investigated by means of Semiconductor Bloch Equations. A reduced band-gap renormalization has been found due to partial cancellation between gap shift and exciton binding energy. Furthermore we have demonstrated optical gain occurring at strong pumping regime and discussed its temperature dependence to clarify characteristics of quantum wire lasers in connection with dimensionality.
To clarify the excitonic correlation effects beyond Hartree-Fock approximation, we have applied a self-consistent T-matrix approach on the model with long-range Coulomb interactions. The presence of exciton is taken into account by including correlation between electrons and holes under the ladder approximation. The approach allows detailed discussions on spectra dependence on carrier density and temperature without introducing any phenomenological damping parameter. Knowledge on these optical characteristics may provide important information for developing quantum-wire laser devices.
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