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

这项由普渡大学物理系的A.K. Ramdas教授和S. Rodriguez教授进行的研究，主要是研究一系列具有原子结构、晶格动力学和电子带结构共同特征的四面体配位半导体所表现出的新型光谱现象。将进行丰富的研究计划，包括通过傅里叶变换红外光谱（FTIR）、拉曼光谱和光致发光光谱研究同位素控制钻石、碳化硅多型和II-VI化合物半导体中供体束缚电子和受体束缚空穴的电子状态的性质。此外，压电和磁光谱学将用于推断杂质的位置对称性，以及其束缚态的简并度，变形势常数和g因子特征。此外，利用FTIR研究了II-VIs、I-III-VI2和II-IV-V2黄铜矿中等电子和补偿杂质的局域振动模式和间隙模式，以及II-VI和黄铜矿基稀释磁性半导体中磁激发所揭示的sp-d和d-d交换相互作用。这些和其他现象和系统构成了一个范围广泛的研究项目，其对当代固体物理和材料科学各个领域的贡献将有助于我们理解新材料的基本行为，并有助于将其与各种技术设备相结合。这项研究由普渡大学物理系的A.K. Ramdas教授和S. Rodriguez教授进行，主要研究一系列在原子结构、晶格动力学和电子带结构方面具有共同特征的四面体配位半导体所表现出的新型光谱现象。将进行丰富的研究计划，包括通过傅里叶变换红外光谱（FTIR）、拉曼光谱和光致发光光谱研究同位素控制钻石、碳化硅多型和II-VI化合物半导体中供体束缚电子和受体束缚空穴的电子状态的性质。此外，压电和磁光谱学将用于推断杂质的位置对称性，以及其束缚态的简并度，变形势常数和g因子特征。此外，利用FTIR研究了II-VIs、I-III-VI2和II-IV-V2黄铜矿中等电子和补偿杂质的局域振动模式和间隙模式，以及II-VI和黄铜矿基稀释磁性半导体中磁激发所揭示的sp-d和d-d交换相互作用。这些和其他现象和系统构成了一个范围广泛的研究项目，其对当代固体物理和材料科学各个领域的贡献将有助于我们理解新材料的基本行为，并有助于将其与各种技术设备相结合。该研究是与研究生和博士后研究人员共同进行的。这种合作有助于培养下一代科学家和工程师

9800858Ramdas This research by Professors A.K. Ramdas and S. Rodriguez of the Department of Physics of Purdue University is focused on the investigation of novel spectroscopic phenomena exhibited by a range of tetrahedrally coordinated semiconductors which share common features in their atomic architecture, lattice dynamics, and electronic band structures. A rich program of investigations will be pursued, including the study of the nature of the electronic states of donor-bound electrons and acceptor-bound holes in isotopically controlled diamonds, in silicon carbide polytypes, and in II-VI compound semiconductors by Fourier transform infrared (FTIR), Raman, and photoluminescence spectroscopy. Also piezo- and magneto-spectroscopy will be used to deduce the site symmetry of the impurity, and the degeneracies, deformation potential constants, and g-factors characteristic of its bound states. Further, localized vibrational and gap modes of isoelectronic and compensated impurities in II-VIs, I-III-VI2, and II-IV-V2 chalcopyrites will be studied by FTIR as are the sp-d and d-d exchange interactions as revealed in the magnetic excitations in the II-VI and chalcopyrite based diluted magnetic semiconductors. These and other phenomena and systems constitute a wide ranging research program whose contributions to various areas of contemporary solid state physics and materials science will aid in our understanding of the fundamental behavior of novel materials and assist in their incorporation in varied technological devices. %%% This research by Professors A.K. Ramdas and S. Rodriguez of the Department of Physics of Purdue University is focused on the investigation of novel spectroscopic phenomena exhibited by a range of tetrahedrally coordinated semiconductors which share common features in their atom ic architecture, lattice dynamics, and electronic band structures. A rich program of investigations will be pursued, including the study of the nature of the electronic states of donor-bound electrons and acceptor-bound holes in isotopically controlled diamonds, in silicon carbide polytypes, and in II-VI compound semiconductors by Fourier transform infrared (FTIR), Raman, and photoluminescence spectroscopy. Also piezo- and magneto-spectroscopy will be used to deduce the site symmetry of the impurity, and the degeneracies, deformation potential constants, and g-factors characteristic of its bound states. Further, localized vibrational and gap modes of isoelectronic and compensated impurities in II-VIs, I-III-VI2, and II-IV-V2 chalcopyrites will be studied by FTIR as are the sp-d and d-d exchange interactions as revealed in the magnetic excitations in the II-VI and chalcopyrite based diluted magnetic semiconductors. These and other phenomena and systems constitute a wide ranging research program whose contributions to various areas of contemporary solid state physics and materials science will aid in our understanding of the fundamental behavior of novel materials and assist in their incorporation in varied technological devices. The research is conducted jointly with graduate students and post doctoral research associates. This collaboration serves to train the next generation of scientists and engineers ***