Materials World Network: Correlation of the Structural and Optoelectronic Properties of Grain Boundaries in Polar Covalent Semiconductors

这个材料世界网络项目是伊利诺伊大学厄巴纳-香槟分校和德国哈恩-迈特纳研究所的科学家和学生之间的一项联合研究和教育活动，旨在研究基本问题——在一类被称为极性共价半导体的材料中，晶体之间的边界如何影响它们的光学和电子特性。双硒化铜铟[CuInSe2]等极性共价半导体及其相关材料在大面积器件中具有最大的能量转换效率潜力。该研究项目解决了目前这些材料面临的主要基础科学问题——晶体之间的边界如何影响设备的性能。该奖项的主要目标是生长出大而薄的CuInSe2单晶，晶粒边界明确，可以进行详细的研究和建模。具有纳米级分辨率的先进光学探针方法将用于检查光与材料相互作用的方式以及晶界如何影响行为。结果将是对从AlN到ZnSe的极性共价半导体晶界的全面理解。所应用的晶体生长技术和研究的一般科学问题将对太阳能电池中使用的一类材料产生强烈的影响，它们已被确定为大规模发电中最有前途的可再生能源技术。该项目汇集了德国和伊利诺伊大学领先的基础科学研究小组，并将扩大正在进行的研究活动，并大大增加研究生和本科生的交流。该项目可以增强对极性共价半导体的核心独特特征之一的理解，即它们在存在结构缺陷的情况下发挥作用的能力。该结果将对其他半导体的晶界钝化以及光学器件（如光伏、光发射器和光传感器）的改进具有潜在的意义。国际交流将加强包括美国和德国学生在内的研究人员之间的培训和思想交流。国际合作带来的附加价值是交换应用的研究技术，以及培训美国研究生和本科生掌握德国集团擅长的技术。提议的本科生和研究生与K-12年级学生的互动包括课堂参观、远程研究体验（学生将通过互联网使用UIUC的设施进行实验）和开放参观展览，这将增加学生对科学的理解和欣赏。

This Materials World Network project is a joint research and education activity between scientists and students at University of Illinois at Urbana-Champaign and Hahn-Meitner Institute in Germany to study fundamental issue-how the boundaries between crystals in a class of materials known as polar-covalent semiconductors affect their optical and electronic properties. Polar covalent semiconductors such as copper indium diselenide [CuInSe2] and related materials have the greatest potential for ultimate energy conversion efficiency in a large-area device. This research program addresses the primary fundamental science issue currently facing these materials-how do the boundaries between crystals affect the performance of the device. The primary objective of this award is to grow large, thin single crystals of CuInSe2 joined in well-defined grain boundaries that can be studied and modeled in detail. Advanced optical probe methods with nanoscale resolution will be employed to examine the way in which light interacts with the material and how the grain boundary affects the behaviors. The result will be a comprehensive understanding of grain boundaries in polar covalent semiconductors from AlN to ZnSe in general. The crystal growth techniques applied and the general scientific issues studied would have strong implications for a class of materials used in solar cells, and they have been identified as the most promising renewable energy technology for large-scale power generation. The program brings together the leading fundamental science research groups in Germany and at the University of Illinois, and will expand ongoing research activities and greatly increase graduate and undergraduate student exchange. %%%The project could enhance the understanding one of the core unique features of polar covalent semiconductors, namely their ability to function in the presence of structural defects. The results would have potential implications for grain boundary passivation in other semiconductors, and for improvement in optical devices such as photovoltaics, light emitters, and photosensors. International exchange will provide enhanced training and exchange of ideas between researchers including students in the US and Germany. The value added by the international collaboration is in exchange of research techniques to be applied and training of US graduate and undergraduate students in techniques in which the German group specializes. The proposed undergraduate and graduate students interactions with students in K-12 including classroom visits, distance research experiences where students will perform experiments using the UIUC facilities via the internet and open house exhibits would increase the understanding and appreciation of sciences among the students.