Pattern-Directed Growth of Metal Chalcogenide Nanostructures on Surfaces: Composition and Structure Control

在化学系大分子、超分子和纳米化学项目（MSN）的支持下，德克萨斯大学达拉斯分校的Amy Walker教授正在开发基于溶液的化学合成方法，以制备半导体纳米线和其他表面结构。纳米线的宽度以纳米为单位，也就是百万分之一毫米。本研究中的纳米线由单一半导体材料或两种不同的半导体材料组成，通常称为核壳结构。使用基于溶液的合成技术制造电子产品和其他设备比其他方法更环保，也更便宜，但很难精确地将溶液生长的纳米线放置在表面上以形成电路。Walker教授和她的学生们正在使用一种新的方法，即半导体纳米线沉积在微图案衬底上（SENDOM），以高精度在原地生长半导体纳米线。在这个项目中，基础研究将用于改进和扩展SENDOM，并将演示使用SENDOM创建复杂的电子设备。这些进步可能导致从纳米电子学到传感技术的改进和成本降低。反过来，这将通过改善信息技术的获取、安全和环境质量，产生广泛而积极的社会影响。在这项工作中，开发了简单，稳健，可扩展的表面定向原位生长复杂金属硫系纳米线和异质结构的策略。这些解决了在实际设备中集成复杂纳米组件的关键挑战。在半导体纳米线沉积在微图案衬底（SENDOM）中，纳米线的受控生长发生在浸在合适溶液中的多功能微图案衬底的不同区域之间的界面上。由此产生的纳米线可以有几厘米长，并且可以沿着复杂的路径运行。到目前为止，SENDOM已经在单半导体纳米线上得到了证明。SENDOM的扩展将被开发并用于原位生长金属硫族化物核壳、混合金属和混合硫族化物纳米线。为了充分利用和优化SENDOM，需要清楚地了解硫系前驱体、金属前驱体和络合剂的化学性质如何影响纳米线的生长速度和组成，以及它们与图案表面的相互作用。这将通过对镀液化学的实时监测和沉积材料的多技术表征来解决。最后，将演示使用SENDOM制造基于纳米线的场效应晶体管和存储器。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Macromolecular, Supramolecular and Nanochemistry Program (MSN) in the Division of Chemistry, Professor Amy Walker of the University of Texas at Dallas is developing solution-based chemical synthesis methods to prepare semiconductor nanowires and other structures on surfaces. Nanowires have widths measured in nanometers, or millionths of a millimeter. The nanowires in this study are composed either of a single semiconductor material or two different semiconductors one inside the other, commonly called a core-shell structure. Creating electronics and other devices using solution-based synthesis is more environmentally friendly and cheaper than other methods, but it is difficult to precisely place solution-grown nanowires on surfaces to form circuits. Professor Walker and her students are growing semiconductor nanowires in-place with high precision using a new approach: SEmiconductor Nanowire Deposition On Micropatterned Substrates, or SENDOM. In this project fundamental studies will be used to improve and extend SENDOM, and the creation of complex electronic devices using SENDOM will be demonstrated. These advances could lead to improvements and cost reductions in technologies ranging from nanoelectronics to sensing. This, in turn, will have broad and positive societal impact by improving access to information technology, safety, and environmental quality.In this work simple, robust, and scalable strategies for the surface-directed in-place growth of complex metal chalcogenide nanowires and heterostructures are developed. These address key challenges in the integration of complex nanoassemblies in practical devices. In SEmiconductor Nanowire Deposition On Micropatterned Substrates (SENDOM), the controlled growth of nanowires occurs at the interfaces between dissimilar areas of a multifunctional micropatterned substrate immersed in a suitable solution. The resulting nanowires can be centimeters long and can follow complex paths. To date SENDOM has been demonstrated for single semiconductor nanowires. Extensions of SENDOM will be developed and used to grow in situ metal chalcogenide core-shell, mixed-metal and mixed-chalcogenide nanowires. To fully exploit and optimize SENDOM a clear mechanistic understanding is required of how nanowire growth rate and composition are affected by the chemistry of the chalcogenide precursor, metal precursor and complexing agent, as well as their interactions with the patterned surface. This will be addressed by real-time monitoring of the bath chemistry and multi-technique characterization of the deposited materials. Finally, fabrication of nanowire-based field-effect transistors and memories will be demonstrated using SENDOM.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.