Materials World Network: Electronic Doping in Semiconductor Nanocrystals

该项目涉及明尼苏达大学（UMN）的两个研究小组和德国杜伊斯堡-埃森大学（UDE）的一个研究小组的合作。该研究的目标是合成和研究纳米级半导体晶体（或纳米晶体），其中杂质（或掺杂剂）已被设计纳入。即使没有这种掺杂剂，半导体纳米晶体也可以由于其小尺寸而表现出不同寻常和有用的物理现象。掺杂剂在晶体管等半导体器件中的重要作用为研究掺杂半导体纳米晶体提供了强大的动力。掺杂还可以解决从太阳能电池到生物成像等纳米晶体应用中的关键问题。由于半导体纳米晶体已经有了商业应用（例如，在生物成像中），而且更多的应用也在地平线上（例如，可调谐激光器，发光二极管和太阳能电池），这项研究应该为进一步控制一类有用材料的特性提供帮助。此次合作包括UMN的研究人员，他们是基于溶液的纳米晶体合成专家，以及UDE的研究人员，他们是纳米晶体的化学气相合成专家，并使用扩展x射线吸收精细结构（EXAFS）技术对其进行表征。项目目标包括(i)开发溶液和化学蒸汽合成方法来制备掺杂纳米晶体，以及（ii）使用EXAFS与反向蒙特卡罗（RMC）模拟相结合来确定掺杂的位置。我们应该更好地了解兴奋剂的使用过程。除了科学目标之外，这个材料世界网络项目的一个主要目的是为未来的科学家提供独特的国际研究经验。有这样经历的学生从观察科学如何弥合国际差异中获益良多。在项目过程中，来自UMN的6名本科生和3名研究生将前往德国UDE进行研究。对于本科生，这将被纳入一个海外研究暑期项目。对于研究生，这可以安排在一个方便的时间在他们的论文设计。同样，来自UDE的学生将前往UMN。这些交流也可以通过UDE研究人员访问美国在中心束流线（例如在Argonne国家实验室）进行EXAFS实验来促进。这些访问将允许团队成员之间进行更多的互动，并分析在UMN和UDE制备的样品。

This project involves a collaboration between two research groups at the University of Minnesota (UMN) and one from the University of Duisburg-Essen in Germany (UDE). The goal of the research is to synthesize and study nanometer-scale semiconductor crystallites (or nanocrystals) in which impurities (or dopants) have been incorporated by design. Even without such dopants, semiconductor nanocrystals can exhibit unusual and useful physical phenomena due to their small size. The critical role that dopants play in semiconductor devices such as the transistor provides a strong motivation to study doped semiconductor nanocrystals. Doping can also address key problems in nanocrystal applications from solar cells to bio-imaging. As semiconductor nanocrystals already have commercial applications (e.g., in bio-imaging) and more on the horizon (e.g., tunable lasers, light emitting diodes, and solar cells), the research should provide further control over the properties of a useful class of materials. The collaboration includes researchers at UMN who are experts in solution-based synthesis of nanocrystals and at UDE who are experts in the chemical vapor synthesis of nanocrystals and their characterization using the extended X-ray absorption fine structure (EXAFS) technique. Project objectives include (i) the development of solution- and chemical-vapor-synthetic-methods to prepare doped nanocrystals and (ii) the use of EXAFS in conjunction with reverse Monte Carlo (RMC) simulations to determine the location of the dopant. A better understanding of the doping process should result.In addition to the scientific goals, a major aim of this Materials World Network project is to provide future scientists with unique international research experiences. Students with such experiences benefit firsthand from observing how science bridges international differences. During the course of the project, 6 undergraduates and three graduate students from UMN will travel to Germany to perform research at UDE. For the undergraduate students, this will be incorporated into a research abroad summer program. For the graduate students, this can be arranged at a convenient time during their thesis project. Similarly, students from UDE will travel to UMN. These exchanges can also be facilitated by visits of UDE researchers to the US to perform EXAFS experiments at central beam lines (e.g., at Argonne National Laboratory). These visits will allow additional interactions between team members as well as analysis of samples prepared both at UMN and UDE.