Dynamics of Nanometer Gap Formation in Thermo-Tunneling Devices for Energy Conversion

热隧穿是一个术语，用于描述热电子的联合发射（热离子发射）和电子穿过两个表面之间的狭窄势垒的隧道（场发射）。热电子在几纳米间隙上的热隧穿已应用于真空电子学和平板显示器，并在热电冷却和能源生产方面具有巨大的潜力。热隧穿纳米结构的理论和实验研究表明，这些结构的散热效率可以接近理论极限，即卡诺效率。该项目旨在通过在两个非常光滑的表面上形成一个非常窄（1纳米宽）的真空间隙来测试一种构建热隧道器件的新方法。不幸的是，在实际使用热隧穿装置所需的足够大的面积上建立纳米级真空间隙是非常具有挑战性的，迄今为止还没有得到证明。因此，本提案的目标是探索和证明利用洛伦兹、范德华力和静电力之间的动态平衡在扩展区域上产生纳米级真空间隙的可行性。本文将运用现代动力系统分析和分布参数系统边界控制的方法，从理论上和实验上论证形成这种间隙的可行性，并生产出一类新型的高效能量转换装置。如果成功，该研究将产生一种新的纳米缝隙形成技术，可用于固态冷却设备、固态热电发电机和用于防御（防辐射）应用的高速真空电子设备。这种装置的能量转换效率接近热力学（卡诺）极限，因此，该项目可以通过取代冷却应用中的机械压缩机，或生产更高效的热电发电机，在冷却和发电应用中节省大量能源。该研究将为亚利桑那大学应用数学跨学科项目的研究生提供宝贵的培训机会，并为布达佩斯技术与经济技术大学应用力学系的研究生提供交流机会。

Thermo-tunneling is a term used to describe combined emission of hot electrons (thermionic emission) and tunneling of electrons through a narrow potential barrier between two surfaces (field emission). Thermo-tunneling of hot electrons across a few-nanometer gap has application to vacuum electronics and flat panel displays, and holds great potential in thermo-electric cooling and energy generation. Theoretical and experimental studies on thermo-tunneling nano-structures have shown that the heat removal efficiency of these structures could approach the theoretical limit known as Carnot efficiency. This project aims to test a new method for constructing thermo-tunneling devices by forming a very narrow (1 nanometer wide) vacuum gap across two very smooth surfaces. Unfortunately, establishment of a nanometer vacuum gap over sufficiently large areas required for practical use of thermo-tunneling devices is very challenging and so far has not been demonstrated. The goal of this proposal, therefore, is to explore and demonstrate the feasibility of creating nanometer vacuum gaps over extended areas using a dynamic equilibrium between Lorentz, Van der Waals, and electrostatic forces. The methods of modern dynamical system analysis and boundary control of distributed parameter systems will be applied to demonstrate theoretically and experimentally the feasibility of forming such gaps and to produce a new class of high-efficiency energy conversion devices. If successful, the proposed research will result in a novel nanometer gap-forming technique that can be used in solid-state cooling devices, solid-state thermoelectric generators, and high-speed vacuum electronic devices for defense (radiation hard) applications. The energy conversion efficiency of such devices approaches the thermodynamic (Carnot) limit, therefore the project could lead to tremendous energy savings in cooling and power-generation applications by replacing mechanical compressors in cooling applications, or producing a more efficient thermo-electric generators. The research will provide invaluable training opportunities for graduate students in the Applied Mathematics Interdisciplinary Program at the University of Arizona and for graduate student exchange with the world-renowned Department of Applied Mechanics at the Budapest Technical University of Technology and Economics.