EFRI 2-DARE: Energy Efficient Electronics with Atomic Layers (E3AL)

最近的科学进展已经分离出仅1至3个原子层厚的纳米材料，具有半金属（例如石墨烯）、半导体（例如二硫化钼）和绝缘特性（例如氮化硼）。与众所周知的块状材料如硅不同，这些原子级薄的材料没有悬挂键，同时在原子层的平面中具有高的电导率和热导率，但在垂直于原子层的方向上具有非常低的电导率。在这个项目中，斯坦福大学团队（Pop，Goodson，Saraswat，Wong）将探索由计算机模拟指导的基本测量，利用原子薄材料的独特各向异性特性。该团队还将专注于热电测量，这是一个关注较少的领域。这项研究的应用可能包括产生很少热量的节能电子产品，以及用于可穿戴传感器和医疗设备的灵活能量采集器。从这项工作中产生的许多好处和见解也可以适用于传统电子产品，从而进一步提高国家科学基金会，社会和教育的投资回报率。该项目将教育学生从高中实习生到本科生和研究生的研究人员，他们将在斯坦福大学设计学院接受独特的培训计划。该计划旨在创造？T型？工程师（具有纳米技术的技术深度和跨学科合作的横向能力）。这项研究的技术目标分为五个方面：（1）对原子级薄材料和器件进行建模和仿真，指导其设计和组装。计算探索将支持电学、热学和热电实验。(2)大规模合成和集成原子层到电子和热电器件。原子层将组装成具有受控角取向的异质堆叠。(3)检查和改善原子级薄材料的电气接口，学习如何将它们与外部世界连接。球队将利用兴奋剂，两者兼而有之？表面？然后呢？边缘？接触以最小化电接触电阻。(4)热和热电特性。研究人员将检查热界面和探测热导率的动态变化，特别是在原子层的交叉平面方向。这些可以实现热二极管和热电等应用。(5)通过将基本理论和任务#1-4中的实验联系在一起的方法，启用节能设备和电子设备。该团队将研究利用内置热电效应来转移或操纵热点的晶体管和存储器的可能性，以及用于柔性基板和自然散热受到限制的移动的环境的分层热电模块的可能性。该项目的智力意义的一个关键部分是，它结合了三个学科的专业知识：电气，热/机械和材料工程。团队负责人拥有在多学科环境中与学生合作和共同提供建议的经验;他们还将在指导妇女和代表性不足的少数民族方面建立良好的记录（他们已经在学术界和工业界任职）和在线教学的良好记录，包括在NSF上发布的讲座和模拟代码-斯坦福大学的环境非常适合将基础科学进步转化为长期的工业伙伴关系，该团队还将与空军研究实验室合作进行热电测量，与桑迪亚国家实验室合作进行原子薄接触，并在国际上与IMEC（比利时）和东京大学合作进行材料合成和材料集成的实验方法。

Recent scientific progress has isolated nanomaterials that are only 1 to 3 atomic layers thick, with semi- metallic (e.g. graphene), semiconducting (e.g. molybdenum disulphide) and insulating properties (e.g. boron nitride). Unlike well-known bulk materials such as silicon, these atomically thin materials have no dangling bonds, while possessing high electrical and thermal conductivity in the plane of the atomic layers, yet very low conductivity in the direction perpendicular to the atomic layers. In this project, the Stanford team (Pop, Goodson, Saraswat, Wong) will explore fundamental measurements guided by computer simulations, leveraging the unique anisotropic properties of atomically thin materials. The team will also focus on thermoelectric measurements, an area that has received less attention. Applications of this research could include energy-efficient electronics generating little heat, and flexible energy harvesters for wearable sensors and medical devices. Many of the benefits and insights generated from this work could also be applicable to conventional electronics, thus further improving the return on investment for the National Science Foundation, for society, and for education. The project will educate students from high school interns through undergraduate and graduate researchers, who will be exposed to a unique training program at the Stanford Design School. This program seeks to create ?T-shaped? engineers (with technical depth in nanotechnology and lateral ability to collaborate across disciplines). The societal impact of such a new workforce could be just as important as that of the novel nanoscience and nanotechnology enabled by the proposed research.The technical goals of the research are organized into five tasks: (1) Modeling and simulation of atomically thin materials and devices, guiding their design and assembly. Computational exploration will support the electrical, thermal and thermoelectric experiments. (2) Large scale synthesis and integration of atomic layers into electronic and thermoelectric devices. Atomic layers will be assembled into heterogeneous stacks with controlled angular orientation. (3) Examine and improve electrical inter- faces to atomically thin materials, learning how to connect them to the outside world. The team will leverage doping, and both ?surface? and ?edge? contacts to minimize electrical contact resistance. (4) Thermal and thermoelectric characterization. The researchers will examine thermal interfaces and probe dynamic changes to thermal conductivity, particularly in the cross-plane direction of the atomic layers. These could enable applications like thermal diodes and thermoelectrics. (5) Enable energy- efficient devices and electronics through an approach that ties together the fundamental theory and experiments from Tasks #1-4. The team will examine the possibility of transistors and memory that leverage built-in thermoelectric effects to shift or manipulate hot spots, and that of layered thermoelectric modules for flexible substrates and mobile environments where natural heat sinking is restricted. A key part of the intellectual significance of this project is that it combines expertise from three disciplines: Electrical, Thermal/Mechanical and Materials Engineering. The team leaders have experience collaborating and co-advising students in a multi-disciplinary environment; they will also build on a strong track record of mentoring women and underrepresented minorities (who have gone on to positions in academia and industry) and a strong record of online teaching and learning, including lectures and simulation codes posted on the NSF-sponsored nanoHUB.org. The Stanford environment is uniquely suited for translating fundamental scientific advances to long-term industrial partnerships, and the team will also partner with the Air Force Research Labs for thermoelectric measurements, with Sandia National Labs for atomically thin contacts, and internationally with IMEC (Belgium) and University of Tokyo for material synthesis and experimental approaches for materials integration.