Collaborative Research: Quantum Dot Nucleation in Glass Microsphere Resonators

本研究是与美国加州大学戴维斯分校Risbud教授的合作项目，研究玻璃微球中半导体量子点纳米晶体的激光诱导成核。二氧化碳激光束加工将用于熔化玻璃纤维的尖端，导致微球形成和随后的量子点成核。初步结果表明，该方法可以在直径10 ~ 200微米的微球中形成CdTe量子点。本研究的主要目的是研究玻璃微球的成核和生长特性，以实现控制加工和纳米结构的形成。微球中的半导体量子点将通过电子显微镜（SEM， TEM， HRTEM），小角度x射线散射（SAXS）和利用微球的高Q光共振的超灵敏光谱学来表征。在这些光学模式下，光可以绕微球的赤道旋转数百万次，允许多次采样，并与球中的纳米粒子强相互作用。我们将开发使用微球作为“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体的材料制成的光学器件的纳米技术提供了强大的科学基础。它也有重要的实际应用，如超紧凑和可调谐的光源和激光器。研究生教育项目将包括代表性不足的群体。

This research is a collaborative project with Prof. Risbud from University of California at Davis 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 (10-200 micrometers 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.