Ballistic heat transport in thin oxide layers

薄氧化层中的弹道热传输

• 批准号: 289649665
• 负责人: Professorin Dr. Saskia F. Fischer
• 金额: --
• 依托单位: Arbeitsgruppe Neue Materialien
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/289649665?language=en
• 关键词: Ballistic; heat; transport; thin; oxide

In this project we will continue and finish of our investigations of the thermal conductivity in the transition region from diffusive to ballistic heat transport. Our goal is to identify unambiguously the regime of ballistic phonon transport. As a model system with a large potential for applications, e.g. in power electronics, we will investigate beta-Gallium Oxide as epitaxially grown layers and heterolayers. In these materials the phonon contribution dominates in the heat transport. Due to the temperature dependence of scattering lengths the change to ballistic transport can be adjusted for these layers. The changeover to ballistic transport, known as Casimir limit, is expected if the scattering length exceeds the sample thickness. Here, the thermal conductivity is no longer determined by the Fourier equation but by geometry and boundary conditions. In this regime experimental data is rare. Based on our results from the first funding period of the project on the electrical and thermal transport in single crystals and epitaxial layers we will employ the implemented measurement techniques to layers of ultra-low doping. The phonon scattering responsible for heat transport will be investigated as a function of temperature, layer thickness and doping level. For these thin layers, the methods of growth technology and thermal transport measurements must be further developed to capture the limiting case. Our experimental and methodical results will contribute to the fundamental understanding of thermal transport in ultra-thin electronic layers and add to solving the important issue of heat dissipation from an active electronic layer to a substrate in the case of application. Here, inefficient heat dissipation limits the performance of microelectronic devices, in particular for high power operation.

在这个项目中，我们将继续并完成我们的研究在过渡区从扩散到弹道热传输的热导率。我们的目标是明确地确定弹道声子输运的制度。作为一个具有巨大应用潜力的模型系统，例如在电力电子领域，我们将研究β-氧化镓作为外延生长层和异质层。在这些材料中，声子贡献在热传输中占主导地位。由于散射长度的温度依赖性，可以针对这些层调整弹道传输的变化。如果散射长度超过样品厚度，则预期转换为弹道传输，称为卡西米尔极限。在这里，导热系数不再由傅立叶方程决定，而是由几何形状和边界条件决定。在这方面的实验数据是罕见的。基于我们在单晶和外延层中的电和热传输项目的第一个资助期的结果，我们将采用实施的测量技术来测量超低掺杂层。负责热传输的声子散射将作为温度，层厚度和掺杂水平的函数进行研究。对于这些薄层，生长技术和热输运测量的方法必须进一步发展，以捕捉极限情况。我们的实验和方法的结果将有助于在超薄电子层的热传输的基本理解，并添加到解决的重要问题的散热从有源电子层的基板的情况下的应用。这里，低效的散热限制了微电子器件的性能，特别是对于高功率操作。