CAREER: Position-Controlled Doping of Semiconductor Nanocrystals

这一职业计划的科学目标有两个：(1)开发一种制备位置可控杂质掺杂的高质量半导体纳米晶的一般方法，以及(2)系统地研究各种半导体纳米晶中位置可控掺杂的物理后果。采用三步胶体合成法对半导体纳米晶进行掺杂。在这种合成中，杂质掺杂只发生在纳米晶体的生长阶段，这使得掺杂水平和掺杂在球形纳米晶体中的径向位置可以很容易地控制。控制这些材料参数的能力将创造一个新的机会来定制半导体纳米晶体的光学、电子和磁性。这项研究的成功应用将为开发生物医学诊断、光催化剂、太阳能电池、LED、自旋电子器件等技术应用提供一种新型的掺杂纳米结构。这些纳米晶还将提供独特的纳米级半导体系统，用于系统地阐明量子系统与位置可调掺杂之间的基本相互作用。这一进展将为功能纳米材料的合理设计开辟新的方向，并将进一步为基于纳米晶体的应用创造新的机会。在教育领域，这个职业项目为不同层次的学生开发纳米技术教育：(1)分析化学的本科课程开发，(2)新的纳米技术研究生课程，以及(3)面向高中生的纳米合成实验。非技术摘要作为现代科学中最令人兴奋的前沿领域之一，纳米科学创造了深刻影响从疾病诊断标签到计算机和其他消费电子产品的高密度数据存储等各种技术的机会。要生产如此先进的技术，需要完全掌握制造具有新功能的纳米材料的科学，这是这个职业发展项目的主题。该项目概述了三项广泛的科学任务：(1)半导体纳米晶与磁性杂质的径向位置控制掺杂；(2)半导体纳米晶与常规杂质的掺杂；以及(3)半导体纳米晶与磁性杂质和常规杂质的共掺杂。拟议的研究工作将导致一种新型的基于掺杂的纳米结构，用于开发技术应用，如高灵敏度的生物医学诊断(用于癌症的早期检测)、更高效的太阳能电池，以及用于下一代计算机的自旋电子器件。这个职业项目发生在纳米技术领域，是化学、物理和材料科学的交叉点。这个项目的多学科性质使其对于培养学生(高中、本科和研究生水平)具有必要的知识、理解和技能，以在新兴的纳米技术世界中提供领导能力来说是独一无二的。

Technical AbstractThe scientific goal of this CAREER project is two-fold: (1) to develop a general approach for making high-quality semiconductor nanocrystals doped with position-controlled impurities, and (2) to systematically study the physical consequences of position-controlled doping in various semiconductor nanocrystals. A three-step colloidal synthesis will be developed for doping semiconductor nanocrystals. In this synthesis, impurity doping only occurs in the nanocrystal growth stage, which allows for the easy control of doping levels and the radial positions of dopants in a spherical nanocrystal. The ability to control these material parameters will create a new opportunity to tailor the optical, electronic and magnetic properties of semiconductor nanocrystals. The successful application of this research will provide a new type of doping-based nanostructure for developing technological applications in biomedical diagnosis, photocatalysts, solar cells, LEDs, spintronic devices, etc. These nanocrystals will also provide unique, nanometer-scale semiconductor systems for systematically elucidating the fundamental interactions between quantum systems and position-tunable dopants. This advance will open a new direction to the rational design of functional nanomaterials, and it will further create new opportunities for nanocrystal-based applications. In the area of education, this CAREER project develops nanotechnology education for students at various levels: (1) undergraduate curriculum development for analytical chemistry, (2) a new graduate course on nanotechnology, and (3) nano-synthesis experiments for high-school students.Non-technical AbstractAs one of the most exciting frontiers in modern science, nanoscience has created opportunities to profoundly impact technologies that run the gamut from labels for disease diagnosis to high-density data storage for computers and other consumer electronics. To produce such advanced technologies requires totally mastering the science of fabricating nanomaterials with new functions, which is the subject of this CAREER-development project. This project outlines three broad scientific tasks: (1) radial-position-controlled doping of semiconductor nanocrystals with magnetic impurities; (2) doping of semiconductor nanocrystals with conventional impurities; and (3) co-doping of semiconductor nanocrystals with magnetic and conventional impurities. The proposed research work will lead to a new type of doping-based nanostructure for developing technological applications such as highly sensitive biomedical diagnosis (for early-stage detection of cancer), more efficient solar cells, and spintronic devices for the next generation of computers. This CAREER project takes place in the field of nanotechnology at the intersection of chemistry, physics, and material sciences. The multi-disciplinary nature of this project makes it unique for educating students (at the high-school, undergraduate, and graduate levels) with the necessary knowledge, understanding, and skills to provide leadership in the emerging world of nanotechnology.