Dynamics of Local Vibrational Modes in Semiconductors

技术上的。该项目主要通过振动寿命测量来解决半导体、铁电和孤岛中的氢缺陷。一个主要的目标是利用双色泵浦-探测瞬时漂白方法直接测量同一缺陷的两个局部振动模之间的振动能量转移。该项目旨在全面研究模型晶体半导体和金属氧化物的振动寿命、微观动力学和能量吸收。重点放在宽禁带和质子导电氧化物上，包括氧化锌、氧化镁、二氧化锡、二氧化钛、钛酸钡、钛酸锶和钛酸钾。直接探测这些路径和速率的能力允许在新的精度水平上测试理论和标度定律。动力学研究将对离子环境与O-H振动的耦合以及质子在氧化物晶格内的迁移提供新的见解。杰斐逊实验室自由电子激光的高功率可调谐红外辐射将被用来研究质子导电氧化物中的光致氢扩散。这项拟议的研究有望使人们对电子和光子材料中的基本能量传递过程有新的基本理解。非技术性。该项目涉及具有技术相关性的电子和光子材料科学专题领域的基础研究问题。该项目集研究和教育于一体，为研究生和本科生提供实验室经验和培训，同时进行包括现代光学、材料科学和计算建模在内的跨学科领域的前沿研究。

Technical. This project addresses hydrogen defects in semiconductors, ferroelectrics, and insula-tors primarily through vibrational lifetime measurements. A major goal is to directly measure the vibrational energy transfer between two local vibrational modes of the same defect utilizing a two-color pump-probe transient bleaching approach. The project aims for a comprehensive study of vibrational lifetimes, microscopic dynamics and energy absorption in model crystalline semi-conductors and metal oxides. The focus is on wide band-gap and proton conducting oxides, in-cluding ZnO, MgO, SnO2, TiO2, BaTiO3, SrTiO3, and KTaO3. The ability to directly probe these pathways and rates allows tests of theory and scaling laws at new levels of precision. Dy-namical studies will provide new insight into the coupling of the ionic surroundings to the O-H vibration and the migration of protons within the oxide crystal lattice. The high-power tunable infrared radiation from the Free-Electron Laser at Jefferson Laboratory will be utilized to inves-tigate photo-induced H diffusion in proton conducting oxides. The proposed research is expected to lead to new fundamental understanding of basic energy transfer processes in electronic and photonic materials. Non-Technical. The project addresses fundamental research issues in a topical area of electronic and photonic materials science having technological relevance. The project integrates research and education providing graduate and undergraduate students with laboratory experience and training while conducting forefront research in an interdisciplinary field including modern optics, materials science and computational modeling.