NER: Modulation doped colloidal quantum dots and solution-based semiconductor nanowires

这项研究的目的是开发一种基于溶液的胶体量子点和半导体纳米线的通用掺杂策略。这种方法是基于调制掺杂的概念，该概念最初是为块状半导体开发的。在拟议工作的背景下，这项研究具体涉及将胶体量子点和纳米线与另一种芯/壳或同轴配置的半导体钝化。掺杂原子将同时被引入到外部半导体包层中，由于界面处有利的能带偏移，使得目标材料能够在空间上间接掺杂。这种方法绕过了与纳米结构材料的直接替代掺杂相关的长期问题。这项拟议工作的学术价值包括开发一种替代的、但通用的纳米材料掺杂策略。它还解决了基于溶液的半导体纳米线的掺杂问题，这一问题尚未完成。这项工作的更广泛的影响包括可能开发基于纳米线的设备，涉及分支纳米线的形态，例如具有三脚架、v形和y形的那些。更直接的应用包括可能开发用于生物标记应用的双造影剂。这是通过保持天然纳米结构的高荧光量子产率，同时将自旋活性杂质引入外包层来实现的。这样的纳米结构可以通过荧光、共振、能量转移和/或磁共振成像等发散技术进行成像。更广泛的影响：所有拟议的研究都与PI和Co-PI的教育倡议挂钩，以使本科生和当地高中教师接触到新兴的纳米科学领域。

The objective of this research is to develop a generic doping strategy for solution-based colloidal quantum dots and semiconductor nanowires. The approach is based on the concept of modulation doping, first developed for bulk semiconductors. Within the context of the proposed work, this study specifically entails passivating colloidal quantum dots and nanowires with another semiconductor in a core/shell or coaxial configuration. Dopant atoms will simultaneously be incorporated into the outer semiconductor cladding, enabling the spatially indirect doping of the targeted material because of favorable band offsets at the interface. This approach bypasses longstanding problems associated with the direct substitutional doping of nanostructured materials. The intellectual merit of the proposed work includes the development of an alternative, yet generic, doping strategy for nanoscale materials. It also addresses the doping of solution-based semiconductor nanowires, which has yet to be accomplished. The broader impact of the work includes the possible development of nanowire-based devices involving branched nanowire morphologies such as those with tripod, v-, and y-shapes. More immediate applications include the possible development of dual contrast agents for biological tagging applications. This is achieved by preserving the high fluorescence quantum yields of native nanostructures while simultaneously incorporating spin active impurities into an outer cladding layer. Such nanostructures can then be imaged via divergent techniques such as fluorescence resonance energy transfer and/or magnetic resonance imaging. Broader Impact:All proposed studies are tied into educational initiatives by the PI and Co-PI to expose undergraduates and local area high school teachers to the emerging field of nanoscience.