Dynamics of Local Vibrational Modes in Semiconductors

技术。该项目主要通过振动寿命测量来解决半导体、铁电体和绝缘体中的氢缺陷。一个主要的目标是利用双色泵探瞬态漂白方法直接测量同一缺陷的两个局部振动模式之间的振动能量传递。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。重点是宽带隙和质子导电氧化物，包括ZnO， MgO, SnO2, TiO2, BaTiO3， SrTiO3和KTaO3。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比例定律。动力学研究将为离子环境与O-H振动的耦合以及氧化物晶格内质子的迁移提供新的见解。杰弗逊实验室自由电子激光器的高功率可调谐红外辐射将用于研究质子导电氧化物中的光诱导H扩散。该研究有望对电子和光子材料的基本能量传递过程产生新的基本认识。非技术。本项目旨在解决电子与光子材料科学中具有技术相关性的主题领域的基础研究问题。该项目将研究与教育相结合，为研究生和本科生提供实验室经验和培训，同时在包括现代光学、材料科学和计算建模在内的跨学科领域进行前沿研究。

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.