NIRT: Bottom Up Assembly of Metal and Semiconductor Nanowires: Fundamental Forces to Nanoelectronic Circuits

摘要本文是在纳米尺度科学与工程计划（NSF 02-148）中收到的，类别为NIRT。该项目的技术目标是通过控制基本力来实现纳米粒子的自下而上组装。与自上而下的纳米粒子组装相比，自下而上的组装提供了一种廉价的方法来制造大量的纳米材料，包括高密度的纳米电子学。其中一名研究人员开发了有前途的方法来生产纳米组件，包括珠模板组装和dna定向珠模板组装。通过工程的基本力（例如，范德华，溶剂化，耗竭），该建议寻求最小化不希望的聚集和控制非确定性或确定性组装。在这项研究中了解到的基本纳米粒子力原理将在基于量子力学思想的功能逻辑电路的构建中进行测试，同样的原理将为扩大该电路的生产数量提供基础。要构建的逻辑电路由半导体纳米线（如硅、砷化镓）的六角形或方形阵列以及金属（如金、铂）栅极线组成。这个项目有五个目标。1)该装置的简单版本将在宾夕法尼亚州立大学纳米实验室使用电流体技术，用更大的导线制造。这将有助于开发电路测试程序，以便以后使用定向组装构建的电路进行测试。2)一种不确定的头模板技术将利用物理力（如静电、位阻、溶剂化）自下而上组装各种类型的功能纳米线。这项工作的关键是筛选不可控聚集的共溶剂/颗粒系统，这将大大受益于用分子水平模拟模拟的相图。3)独特的球棒颗粒间力测量将与分子动力学模拟协同产生预测模型和启发式方法，这些模型和启发式方法将广泛适用于稳定纳米颗粒分散，例如最小化范德华力和最大化稳定溶剂化力。4) DNA定向组装的珠粒模板将与第三个目标的启发式方法相结合，以指导组装，同时防止DNA以所需配置连接纳米线时不希望的粒子相互作用。不希望的聚合一直是其他非常有前途的技术的关键障碍。在子项目2和子项目4中，电路将包含化学特异性，例如，实现金属-半导体结，促进目标1，因为纳米电路需要连接到足够大的仪器以进行有用的测量。这个项目产生的更广泛的影响将是提高公众通过亲身体验做出“纳米”决策的能力。纳米技术有许多新的能力，其中一些即使是受过技术教育的公众也不熟悉。公众必须对纳米技术有足够的经验，以作出合乎道德和投票的决定。为了让公众获得纳米技术的“实践”经验，我们将在宾夕法尼亚州州立大学的“宾夕法尼亚中部艺术节”举办半年一次的工作坊。该活动每年吸引约20万参与者，提供了一个非常公开的论坛。要验证的假设是，随着公众的参与，他们对接受技术和决策投票的舒适度将得到提高。另一项重要的活动将是“教老师教纳米”，通过“教师研究经验”类型的项目来建立宾夕法尼亚州立大学k-12教师的知识，将我们自己的专业知识运用到当地学生和他们的父母身上。在这部分课程中，与当地k-12教师的暑期实验工作将使课堂上使用的互动模块的开发成为可能。

NIRT: Bottom Up Assembly of Metal and Semiconductor Nanowires: Fundamental Forces to Electronic CircuitsAbstractThis proposal was received in response to Nanoscale Science and Engineering initiative, NSF 02-148, category NIRT. The technical goal of this project is to enable bottom-up assembly of nanoparticles by controlling fundamental forces. Compared with top-down nanoparticle assembly, bottom-up assembly provides an inexpensive route to making bulk quantities of nanomaterials, including high-density nanoelectronics. Promising methods have been developed by one of the investigators to produce nanoassemblies using bead templating assembly and DNA-directed bead templating assembly. By engineering the fundamental forces (e.g., van der Waals, solvation, depletion), this proposal seeks to minimize undesired aggregation and control either nondeterministic or deterministic assembly. The principles of fundamental nanoparticle forces learned in this research will be tested in the construction of a functional logic circuit based on quantum mechanical ideas, and the same principles will provide a basis for scaling up production quantities of this circuit.The logic circuit to be built consists of hexagonal or square arrays of semiconductor nanowires (e.g., silicon, gallium arsenide), with metal (e.g., gold, platinum) gate wires. This project has five objectives. 1) Simple versions of the device will be built with larger wires at the Penn State Nanofab Facility, using electrofluidic techniques. This will enable development of circuit testing procedures required for later tests with the circuit built using directed assembly. 2) A non-deterministic bead templating technique will exploit physical forces (e.g., electrostatics, steric, solvation) to assemble from the bottom up various types of functional nanowires. Essential to this work is the screening of co-solvent/particle systems that aggregate uncontrollably, and this will benefit greatly from phase diagrams simulated with molecular level simulations. 3) Unique sphere-rod interparticle force measurements will synergize with molecular dynamics simulations to produce predictive models and heuristics that will be broadly applicable in stabilizing nanoparticle dispersions, for instance by minimizing van der Waals forces and maximizing the stabilizing solvation forces. 4) Bead templating with DNA-directed assembly will be combined with the heuristics from the third objective to guide assembly while preventing undesired particle interactions as the DNA links the nanowires in the desired configuration. The undesired aggregation has been a critical barrier to otherwise very promising techniques. In both subprojects 2 and 4, the circuits will contain chemical specificity that enables, for instance, metal-semiconductor junctions, facilitating objective 1, because the nanocircuits will need to connect to instrumentation large enough to take useful measurements.The broader impact resulting from this project will be improved public ability to make "nano" decisions through hands on experience. Nanotechnology has many new capabilities, some, which will be unfamiliar to even the technologically, educated public. It is imperative that the public have sufficient experience with nanotechnology to make ethical and voting decisions. In order that the public gain "hands on" experience with nanotechnology, we will conduct semi-annual workshop booths at the "Central Pennsylvania Festival of the Arts" in State College, Pennsylvania. This event attracts approximately 200 000 participants annually, providing an extremely public forum. The hypothesis to be tested is that as the public participates, their comfort in accepting the technology and voting on decisions will be enhanced.Another important activity will be to "teach teachers to teach nano", building the knowledge of State College Pennsylvania k-12 teachers using "research experience for teachers"-type programs to leverage our own expertise into local students and their parents. For this part of the course, summer lab work with local k-12 instructors will enable the development of interactive modules for use in the classroom.