Investigation of Nanoscale Thermal Transport Across a Point Constriction In Contact and Within a Sub-10 nm Gap

提案编号：1067441 主要研究者：Keunhan Park虽然最近新兴的基于尖端的热应用已经实现了前所未有的纳米级成像，数据存储和制造质量，但它们也对纳米级热传输的基本理解提出了强烈的要求，这些热传输跨越具有纳米级间隙或接触的点收缩。这些技术的空间分辨率是由针尖诱导的局部温度分布决定的。然而，直接测量纳米级热传输和衬底上的局部温度分布还没有成功，主要是由于（1）目前可用的温度计的空间分辨率和灵敏度差;（2）不能精确地控制尖端-衬底距离低于10 nm;以及（3）难以精确地控制高度局部源的温度和精确的温度测量。此外，很少有测量和建模考虑了一个以上的热传递机制在原位环境中的真实的applicationtake.This建议的目的是从根本上了解纳米级的热能传输跨越一个点收缩和由此产生的非均匀加热区的基板。为此，具有与尖端半径一样小的空间分辨率的纳米温度计，即，10 #8722;50 nm将被制造和表征。局部衬底温度将被测量与开发的纳米温度计，而悬臂精确地控制在其温度和尖端位置徘徊与一个子-10 nm的间隙。将开发包括亚连续空气传导、接触处的固体传导和近场辐射的多尺度模型，以了解基于尖端的热应用中的物理学。该项目的成功将提供加热尖端和基底之间纳米级热传输的定量测量，以及尖端附近极局部加热区的温度分布。提出的纳米温度计将提供小于50 nm的传感探针尺寸，其制造和表征将在热科学和工程界得到很好的认可。加热杠杆的亚10 nm间隙控制的系统方法将很容易适用于其他基于AFM的计量和技术，如SThM和纳米制造。此外，耦合之间的尖端和基板的纳米级热传输的数值模拟将推进纳米级的热传递的基本理解跨越一个点constrictions.Broader影响：从测量和模拟的结果将填补知识空白，并提供及时的支持，进一步推进尖端为基础的热应用。这项研究将为一名研究生和一名本科生提供培训机会，其中许多人将从代表性不足的学生群体中招募。为了在纳米教育中发挥协同效应，将启动学院间的长期项目。为了鼓励K-12外展活动，将开发一个用乐高积木建造的AFM，并用于URI的SMILE（科学和数学研究性学习体验）项目。总的来说，本提案所涉及的研究和教育活动将在促进教学、培训和学习的同时提高对科学和技术的认识。

Proposal number: 1067441 PI: Keunhan ParkWhile recently emerging tip-based thermal applications have realized unprecedented quality of nanoscale imaging, data storage, and manufacturing, they have also created strong demands on the fundamental understanding of nanoscale thermal transport across a point constriction with a nanometer scale gap or in contact. The spatial resolution of these technologies is determined by the tip- induced localized temperature distribution. However, direct measurement of nanoscale thermal transport and local temperature distribution on the substrate has not been successful mainly due to (1) poor spatial resolution and sensitivity of currently available thermometers; (2) incapability to precisely control the tip-substrate distance below 10 nm; and (3) the difficulty in the precise temperature control of a highly local source and accurate temperature measurement. Moreover, very few measurement and modeling have considered more than one heat transfer mechanisms together in in-situ environments where real applications take place.This proposal aims to fundamentally understand nanoscale thermal energy transport across a point constriction and resultant non-uniform heated zone of the substrate. To this end, nanothermometers that have a spatial resolution as small as the tip radius, i.e., 10−50 nm will be fabricated and characterized. The local substrate temperature will be measured with the developed nanothermometer while the cantilever is precisely controlled in its temperature and tip position hovering with a sub-10 nm gap. A multiscale model that includes sub-continuum air conduction, solid conduction at the contact, and near-field radiation will be developed to understand the physics in tip-based thermal applications.Intellectual Merit: The success of this project will provide the quantitative measurement of nanoscale thermal transport between a heated tip and substrate across a sub-10 nm air gap and in contact, and temperature distribution of extremely localized heated zone near the tip. Proposed nanothermometers will provide a sensing probe size smaller than 50 nm, fabrication and characterization of which will be well recognized in the thermal science and engineering community. Systematic approaches on the sub-10 nm gap control of heated cantilevers will be readily applicable to other AFM-based metrologies and technologies, such as SThM and nanomanufacturing. In addition, numerical modeling of coupled nanoscale thermal transport between the tip and substrate will advance the fundamental understanding of nanoscale heat transfer across a point constriction.Broader Impacts: The results from the measurements and simulations will fill in a knowledge gap and provide timely support for the further advancement of tip-based thermal applications. The research will provide training opportunities for one graduate student and undergraduate students, many of whom will be recruited from underrepresented group of students. To make synergetic effects in nanoscale educations, inter-institute term projects will be initiated. To encourage K-12 outreach activities, an AFM built with LEGO blocks will be developed and used in the SMILE (Science and Mathematics Investigative Learning Experiences) program at URI. Overall, research and education activities involved in this proposal will enhance scientific and technological understanding while promoting teaching, training, and learning.