Dynamics of Local Vibrational Modes in Semiconductors

技术.本计画主要借由振动寿命量测来探讨半导体、铁电体与绝缘体中的氢缺陷。一个主要的目标是直接测量的两个本地振动模式的同一缺陷，利用双色泵浦探测瞬态漂白方法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。重点是宽带隙和质子导电氧化物，包括ZnO，MgO，SnO 2，TiO 2，BaTiO 3，SrTiO 3和KTaO 3。直接探测这些途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。动力学研究将为氧化物晶格中离子环境与O-H振动的耦合以及质子的迁移提供新的认识。利用Jefferson实验室自由电子激光器的高功率可调谐红外辐射研究质子传导氧化物中光致氢扩散。这项研究有望对电子和光子材料中的基本能量传递过程产生新的基本认识。非技术性。该项目解决了电子和光子材料科学领域的基础研究问题，具有技术相关性。该项目整合了研究和教育，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.