Raman, Brillouin, Infrared and Modulation Spectroscopy of Collective and Localized Excitations in Tetrahedrally Coordinated Semiconductors and their Heterostructures

本文主要研究了四面体配位半导体的振动、电子和磁激励。将研究分子束外延和化学气相沉积制备的体异质结构和亚微米异质结构。II-VI和III-V半导体（体、涂层和量子阱结构）将使用拉曼、布里渊、调制反射率、光致发光和吸收光谱进行检查。磁性离子引入到II-VI化合物中产生了一类新的材料，称为稀释磁性半导体，具有显著的磁光效应。对这些系统的进一步探索将特别强调低维材料。本文还将研究有意引入金刚石和碳化硅中的给体和受体的振动谱和电子能级。该计划的主旨是提供对四面体协调半导体的物理特性的基本理解，其光学特性构成了许多光电应用的基础。四面体配位半导体家族包括众所周知的IV族半导体，如C， Si和Ge，以及ii - v族半导体（如GaAs， InSb等）和II-VIs族半导体（如CdTe， ZnTe等）。这些材料中的磁激发将通过光谱研究使用各种技术进行检测。这种光谱研究的结果将产生与其光学特性相关的重要基本量，并有望形成许多光电器件的基础。特别是，引入II-VIs中的磁性离子会产生引人注目的磁光效应，在磁隔离器和光学传感器方面具有潜在的应用前景。这些新颖的先进材料系统可用于实验和理论研究，这要归功于在大块和亚微米尺寸的新型半导体的生长中日益开发的巧妙技术。这项工作将与几个工业研究实验室的科学家和技术人员合作完成，他们将提供许多材料。此外，该项目得益于与阿贡国家实验室的积极合作。

This research focuses on the vibrational, electronic, and magnetic excitations in tetrahedrally coordinated semiconductors. Both bulk and submicron heterostructures fabricated by molecular beam epitaxy and chemical vapor deposition will be investigated. II-VI and III-V semiconductors (bulk, epilayers, and quantum well structures) will be examined using Raman, Brillouin, modulated reflectivity, and photoluminescence and absorption spectroscopy. Magnetic ions introduced into II-VI compounds have resulted in a new class of materials called diluted magnetic semiconductors which possess striking magneto-optic effects. Further exploration of these systems will be undertaken with special emphasis on materials of low dimensionality. The vibrational spectra and electronic levels of donors and acceptors intentionally introduced into diamond and silicon carbide will also be studied. The thrust of the program is to provide a fundamental understanding of the physical properties of tetahedrally coordinated semiconductors whose optical characteristics form the basis of many optoelectronic applications. %%% The family of tetrahedrally coordinated semiconductors encompasses the well known group IV semiconductors such as C, Si, and Ge as well as the II-Vs (e.g., GaAs, InSb, etc.) and the II-VIs (e.g., CdTe, ZnTe, etc.) The electronic, vibrational, and magnetic excitations in these materials will be examined through spectroscopic investigations using a variety of techniques. The results of such spectral studies will yield important fundamental quantities related to their optical properties and are expected to form the basis of many optoelectronic devices. In particular, magnetic ions introduced into the II-VIs generate striking magneto- optic effects which have potential applications as magnetic isolators and optical sensors. These novel advanced material systems are accessible to both experimental and theoretical studies, thanks to the ingenious techniques increasingly exploited in the growth of new semiconductors in the bulk as well as with submicron dimensions. The work will be done in collaboration with scientists and technologists at several industrial research laboratories who will supply many of the materials. In addition, the program benefits from an active collaboration with the Argonne National Laboratory.