CAREER: Optical and Phonon Interactions in Wide-Bandgap Nano-Structures

本CAREER项目利用拉曼光谱和光致发光光谱研究能够在紫外范围内发光的宽带隙半导体纳米结构的光学特性/相互作用和声子动力学。研究的宽带隙半导体包括GaN、AlN和AlGaN合金，以及ZnO和SiC。研究纳米粒子、量子点和随机结构粉末的发光、晶体结构和晶体对称特性。该方法包括研究单个纳米晶体的特性以及粒子的集合，以探索光发射特性的基本机制，例如给定尺寸和形状的受限结构固有的光谱范围和效率，以及团簇环境的影响。此外，将研究通过晶体振动模式-电子-声子相互作用产生的能量再弛豫通道，以评估受限声子对粒子光学特性的影响。项目第一年重点研究SiC、GaN、AlN、ZnO等纳米结构的光学和材料性质，为后续研究更复杂的混合粒子体系奠定基础。第二和第三年将重点研究粒子群和团簇的光学特性，并建立一种新型的紫外光谱装置，用于远程激发，以研究纳米粒子之间的光相互作用、能量传递、激子扩散和效率损失现象。4年级和5年级将专注于共振拉曼散射研究，以及高压、高温条件下纳米结构的光学和结构行为的研究。该项目涉及具有技术相关性的基础材料科学研究问题。该项目的一个重要特点是非常重视教育，并将研究与教育相结合。与研究计划相结合，将开发新的跨学科课程，包括光学材料和器件的新课程以及材料科学的新本科学位课程。本课程的课程设置既适合高年级本科生，也适合不同学科的研究生。该计划将重点关注与材料科学，物理和材料化学相关的广泛问题，从大规模到分子水平。所提出的研究的影响将有助于纳米晶体的结构和光学特性的基本知识，这是工程上可行的光学器件在紫外线下工作的关键。新课程，加上积极促进学生参与实验研究，可望对学生的教育发展产生广泛影响，长远而言，对高科技产业和学术界都有贡献

This CAREER project addresses optical properties/interactions and phonon dynamics of wide band gap semiconductor nanostructures capable of light emission in the UV range utilizing Raman and photoluminescence spectroscopy. Wide bandgap semiconductors to be investigated include GaN, AlN, and AlGaN alloys, as well as ZnO, and SiC. Research issues concerning light emission, crystal structure and crystal symmetry characteristics of nano-particles, quantum-dots, and random-structured powders will be studied. The approach includes the study of properties of individual nanocrystals as well as ensembles of particles to explore the basic mechanisms of light emission properties such as spectral range and efficiency inherent to a confined structure of a given size and shape, as well as the impact of the cluster environment. Additionally, energy re-laxation channels which occur via crystal vibrational modes--electron-phonon interactions, will be investigated to assess the impact of confined phonons on optical characteristics of particles. Year 1 of the project is focused on investigation of optical and material properties of nano-structures of SiC, GaN, AlN, ZnO, to lay the foundation for the study of more complicated mixed particle systems in the following years. Years 2 and 3 will focus on studies concerning the optical properties of particle ensembles and clusters and on establishing a novel UV-optical spectroscopy setup for remote excitation to enable studies concerning phenomena of light interactions, energy transfer, exciton diffusion, and efficiency losses among nano-particles. Years 4 and 5 will focus on resonant Raman scattering studies, as well as research involving the optical and structural behavior of nanostructures under high-pressure, high-temperature conditions. %%% The project addresses fundamental materials science research issues having technological relevance. An important feature of the project is the strong emphasis on education, and the integration of research and education. In tandem with the research program, new interdisciplinary curricula will be developed including a new course on optical materials and devices and a new undergraduate degree program on the Science of Materials. The course curriculum will be designed for upper level undergraduate students as well as for graduate students from various science disciplines. This program will focus on a broad spectrum of issues related to materials science, physics, and the chemistry of materials from the large scale to the molecular level. The impact of the proposed research will be to contribute towards basic knowledge of the structural and optical characteristics of nanocrystallites, a key to engineering viable optical devices operating in the UV. The new curricula, together with the active promotion of student participation in experimental research, is expected to have broad impact on the educational development of students and in the longer term contribute to both high technology industry and academia.***