Probing Carrier Dynamics in Novel Metal/Semiconductor Nanocomposites

技术摘要：将半金属稀土单肽（RE-V）纳米颗粒外延嵌入III-V半导体中的纳米复合材料是一种令人兴奋的新型电子材料。这些纳米复合材料的独特性质已经改善了从热电到隧道结的原型设备的性能。尽管取得了这些进展，但人们对这些纳米复合材料的基本纳米物理性质仍然知之甚少。例如，载流子的来源和界面对电荷输运和能量弛豫的贡献仍然未知。在这项资助中，表征良好的InAs量子点将被用作单个RE-V纳米颗粒性质的局部探针。单纳米粒子光谱学将由系综超快光学和太赫兹光谱学补充。超快测量将量化纳米复合材料的动态特性，而单纳米粒子光谱将使材料特性的微观理论得以发展。除了可以测量单个纳米颗粒外，量子点的结合将为控制生长形态和生产全新的纳米复合结构提供前所未有的新工具。这项拨款支持从根本上理解与技术相关的纳米复合材料系统的努力。通过这项资助开发的对纳米级物理性质的全面理解将直接导致具有深远影响的实际应用，包括改进的能量收集设备和太赫兹科学技术的重大进步。两名研究生将接触到高度跨学科的环境，当地学校的K-12学生将从教师培训活动中受益，并将向当地学校租借教育设备。

Technical AbstractNanocomposites in which semimetallic rare-earth-monopnictide (RE-V) nanoparticles are epitaxially embedded within III-V semiconductors are an exciting new class of electronic materials. The unique properties of these nanocomposites have already led to improved performance in prototype devices ranging from thermoelectrics to tunnel junctions. Despite this progress, the fundamental nanoscale physical properties of these nanocomposites remain poorly understood. For example, both the source of carriers and the interfacial contributions to charge transport and energy relaxation remain unknown. In this grant, well-characterized InAs quantum dots will be used as a local probe of the properties of single RE-V nanoparticles. The single nanoparticle spectroscopy will be complemented by ensemble ultrafast optical and terahertz spectroscopy. The ultrafast measurements will quantify the dynamic properties of the nanocomposites while the single nanoparticle spectroscopy will enable development of a microscopic theory of material properties. In addition to allowing measurements of single nanoparticles, the incorporation of quantum dots will provide a new tool for unprecedented control over growth morphology and the production of radically new nanocomposite structures.Non-Technical AbstractThis grant supports efforts to fundamentally understand a technologically-relevant nanocomposites system. The comprehensive understanding of nanoscale physical properties developed through this grant will lead directly to practical applications with far-reaching impacts, including improved energy harvesting devices and significant advances in terahertz science and technology. Two graduate students will be exposed to a highly interdisciplinary environment, and K-12 students in local schools will benefit from teacher training activities and also the creation of educational equipment that will be loaned to local schools.