Collaborative Research: Quantum Dot Nucleation In Glass Microsphere Resonators

这项研究是与斯坦福大学Brongersma教授合作的项目，目的是研究半导体量子点(QD)纳米晶在玻璃微球中的激光成核。二氧化碳激光处理将被用来熔化玻璃纤维的尖端，从而形成微球和随后的量子点成核。初步结果表明，用这种方法可以在直径为10 mm-200 mm的微球中形成CdTe量子点。这项研究的主要目的是研究玻璃微球的形核和生长特性，以实现玻璃微球几何形状的可控加工和纳米结构的形成。微球中的半导体量子点将用电子显微镜(扫描电子显微镜、透射电子显微镜、高分辨电子显微镜)、小角X射线散射(SAXS)和利用微球高Q光学共振的超灵敏光学光谱进行表征。在这些光学模式下，光可以围绕微球的赤道运行数百万次，从而实现多次采样，并与球体中的纳米颗粒产生强烈的相互作用。我们将发展利用微球作为“光学微测试实验室”的程序，并为研究各种玻璃微球的成核和生长现象提供一般配方。该项目为基于玻璃微球中含有半导体纳米晶的材料制成的光学器件的纳米技术提供了坚实的科学基础。它还具有重要的实际应用，如超小型和可调谐的光源和激光器。研究生教育计划将包括代表性不足的群体。

This research is a collaborative project with Prof. Brongersma of Stanford University to study the laser induced nucleation of semiconductor quantum dot (QD) nanocrystals in glass microspheres. CO2 laser beam processing will be used to melt the tip of a glass fiber resulting in microsphere formation and subsequent nucleation of QDs. Preliminary results show that we can form CdTe QDs in microspheres (10 mm - 200mm diameter) by this method. The main goal of this research is to investigate the nucleation and growth characteristics to enable controlled processing and nanostructure formation in the glass microsphere geometry. The semiconductor quantum dots in the microspheres will be characterized by electron microscopy (SEM, TEM, HRTEM), small angle X-ray scattering (SAXS), and ultra-sensitive optical spectroscopies that exploit the high Q optical resonances of the microsphere. In these optical modes, light can orbit around the equator of the microsphere for millions of times allowing multiple sampling and strong interaction with the nanoparticles in the sphere. We will develop the procedures for using microspheres as "optical microtest laboratories" and provide general recipes for studying a wide variety of nucleation and growth phenomena glass microspheres.The project provides a strong science base to nanotechnologies based on optical devices made from materials containing semiconductor nanocrystals in glass microspheres. It also has important practical applications such as ultra-compact and tunable light sources and lasers. The graduate educational program will include under-represented groups.