Probing Carrier Dynamics in Novel Metal/Semiconductor Nanocomposites

技术摘要将半金属稀土单硝酸酯(RE-V)纳米颗粒外延嵌入到III-V半导体中的纳米复合材料是一类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导致了从热电到隧道结的各种原型设备性能的提高。尽管取得了这些进展，但这些纳米复合材料的基本纳米级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纳米粒子性质的局部探测器。单纳米粒子光谱学将得到整体超快光学和太赫兹光谱学的补充。超快测量将量化纳米复合材料的动态性质，而单纳米粒子光谱将使材料性质的微观理论得以发展。除了能够测量单个纳米粒子之外，量子点的加入将提供一种新的工具，用于前所未有地控制生长形态和生产全新的纳米复合材料结构。非技术摘要这项赠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。通过这笔赠款开发的对纳米级物理特性的全面了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和技术的重大进步。两名研究生将接触到一个高度跨学科的环境，当地学校的K-12学生将从教师培训活动中受益，并创造将借给当地学校的教育设备。

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.