EAGER - Exploiting Strain-Induced Coupling between Rare Earth Ions and the GaN host for Improved Electroluminescence and Magnetic Devices

本项目的目的是提供关键的证据，证明应变控制是提高掺稀土氮化镓薄膜光学和磁学性能的关键。到目前为止，控制稀土离子与宿主电子系统的期望耦合的隐藏参数的控制可以对发光和磁性设备的材料体系的利用产生变革性的影响。智能的优点基于实验结果，这些发现表明(1)当稀土离子表现出与宿主的强耦合时，稀土离子可以被最有效地激发，(2)磁性状态和产生的磁化强度取决于晶格失配诱导的压电场的方向。该计划应用先进的显微镜和光谱工具，利用样品中现有的或有意引起的应变变化，可靠地探索应变和耦合之间的关系，并确定电致发光和室温铁磁性的最佳应变条件，然后在未来的设备设计中实施。更广泛的影响包括决定性的性能改进，使材料系统成为固态照明和磁性设备应用中有吸引力的、能源高效的候选者。外展活动的目标是让少数族裔学生通过利哈伊物理学参与研究。暑期研究计划和与历史上黑人大学的教师合作。

The objective of this program is to provide the critical proof that the control of the strain is the key for order-of-magnitude improvement of the optical and magnetic properties of epitaxially grown gallium nitride layers doped with rare earth ions. Controlling this so far hidden parameter that governs the desired coupling of the rare earths ion to the electronic system of the host can have a transformative impact for the utilization of the material system for light emitting and magnetic devices.The intellectual merit is based on experimental findings which show (1) that rare earth ions can be excited most efficiently when they exhibit a strong coupling to the host and (2) that the magnetic states and the resulting magnetization depend on the direction of the piezoelectric field that is induced by lattice mismatch. The program applies advanced microscopy and spectroscopic tools and exploits existing or intentionally induced strain variations across samples to reliably explore the relation between the strain and the coupling and to determine the optimized strain conditions for both electro-luminescence and room-temperature ferromagnetism, which can then be implemented in future device designs.The broader impacts include the decisive performance improvements that will enable the material system to become an attractive, energy efficient candidate for applications in solid state lighting and for magnetic devices. The outreach activities target involvement of minority students in the research through Lehigh Physics? summer research program and partnerships with faculty from historically black colleges.