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

本项目致力于利用各种光学技术研究四面体配位半导体及其异质结构中的集体和局部激发。重点研究由轻原子（金刚石、碳化硅、氮化硼和BP）组成的同位素控制半导体中的集体激发和局域激发。将注意到在同位素控制的金刚石、硅、碳化硅多型体以及II-VI和III-V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。此外，在ⅱ-ⅵ和ⅲ- v型半导体黄铜矿系谱中，对等电子和补偿杂质的局域振动和间隙模式进行了探索和描述。本文将研究分子束外延制备的纳米结构在降维约束下的集体激发。将采用拉曼、布里色、红外、光致发光和调制反射率/透射光谱技术，并辅以压电和磁光谱学来解决上述问题。学生将参与这项研究。他们将接受当前半导体物理前沿领域之一的培训，从而为进入21世纪的科学/技术劳动力做好准备。本研究涉及几种实验光学技术在先进半导体材料问题中的应用。这些材料在当前的技术中发挥着巨大的作用，但对它们的行为仍然缺乏基本的了解。这项研究将为金刚石、碳化硅、氮化硼等超硬材料的合成和使用提供有用的信息，这些材料已被用作超硬薄膜涂层。这些材料的行为可以通过有意地、有控制地引入特定杂质或通过操纵它们的同位素组成来改变。这些特性的改变有望改善材料在高温/高功率电子器件中的应用性能。这个项目为学生提供了很多参与的机会。该计划的参与者将接触到一个在当代基础科学和潜在应用中重要的领域的兴奋和智力挑战。由此培养的专业知识将为他们将来在学术界和政府部门工作以及在高科技光电行业从事研究和开发工作做好准备。

This project is devoted to the investigation of collective and localized excitations in tetrahedrally coordinated semiconductors and their heterostructures by means of a variety of optical techniques. The research will focus on the collective and localized excitations in isotopically controlled semiconductors composed composed of light atoms (diamond, SiC, BN and BP). Attention will be given to electronic states of donor-bound electrons and acceptor-bound holes in isotopically controlled diamond, Si, silicon carbide polytypes, as well as II-VI and III-V compound semiconductors. In addition, localized vibrations and gap modes of isoelectronic and compensated impurities will be explored and delineated in the chalcopyrites genealogically derived from the II-VI and III-V semiconductors. Collective excitations subjected to the constraints of the reduced dimensionality of nanostructures fabricated with molecular beam epitaxy will be investigated. Raman, Brillouin, Infrared , photoluminescence and modulated reflectivity/transmission spectroscopic techniques supplemented by piezo- and magneto-spectroscopy will be employed to address the above problems. Students will participate in this research. They will receive training in one of the forefront areas of current semiconductors physics and will thereby be prepared to enter the scientific/technical workforce of the 21st Century. This research deals with the application of several experimental optical techniques to problems posed by advanced semiconductor materials. These materials play a great role in current technology but a basic understanding of their behaviors is still lacking. This research will provide information that will be useful for the synthesis and use of ultrahard materials, such as diamond, silicon carbide, boron nitride and others that have found applications as superhard thin film coatings. The behavior of these materials can be changed by the deliberate, controlled introduction of specific impurities or by manipulating their isotopic composition. The changed behaviors hold the promise of improved performance of the materials in applications of high temperature/high power electronic devices. This project offers many opportunities for the participation by students. Participants in the program will be exposed to the excitement and intellectual challenges of an area that is important in contemporary basic science and significant for potential applications. The expertise thus developed will prepare them for a future in academia and government as well as a career in research and development in the high tech optoelectronic industry.