New Type of Semiconductor Lasers with Quantum-Well Wire Structures and Quantum-Well Box Structures

点击翻译按钮获取中文摘要

It is important to investigate effects of quantum wire and quantum box structure on lasing properties in semiconductor lasers for future optical information and communication systems. For this purpose we started cooperative research with professors of California Institute of Technology. In this research project, we do research on (1) Realization of quantum wire and quantum box effects in semiconductor lasers by placing a quantum well laser in a high magnetic field. (2) To clarify ultimate limit of lasing properties in the quantum box lasers (3) physics of electronic states and optical properties in quantum wire and box lasers including band theory. From University of Tokyo Prof. Arakawa, Prof. Sakaki, Prof. Ikoma, Mr. Sogawa, and Mr. Takahashi and from California Institute of Technology, Prof. Yariv and Prof. Vahala participated in this project. Moreover, Dr. Schulman, Hughes Research Institute, former visiting Researcher in Caltech also joined this project.For the high magnetic field … More experiment, we used high magnetic field facilities in Frnacis Bitter Maenet Laboratory of Massachusetts Institute of Technology, U.S.A. carrying samples, sample holders, various kinds of measurement equipment from Japan and west coast. In the experiment we clarified quantum box effects through the measurement of anisotropic properties of photoluminescence and lasing properties rotating the quantum well lasers in the high magnetic field. We believe that our experiment has been successful and clarified several important characteristics.We also study ultimate lasing characteristics of quantum wire and quantum box lasers. Threshold current, modulation dynamics, and spectral properties were discussed. In addition, several problems raised in such microstructure lasers such as size variation and nonlinear gain effects were investigated.Electronic states which are important for predicting lasing characteristics were also intensively discussed using the tight binding method. Band structures including the valence band of quantum wires were clarified, showing that the nonparabolicity and negative effective mass natures are more pronounced with the increase of the quantum confinement. Moreover, we discussed effects of incorporation of the strain effect in the quantum wires.Moreover we also exchange technical information on recent results on fabrication technology for quantum wires and boxed. Caltech group are studying MOCVD growth on SiO2 patterned substrates, while University of Tokyo group are investigating both tilted super lattice structures grown by MBE and electron beam assisted MOCVD. Both groups are now successful to achieve quasi-quantum wire structures. However, we still need one breakthrough for realizing real quantum wire and box structures. Less