Silicon-based nanocomposites for thermoelectric applications

用于热电应用的硅基纳米复合材料

• 批准号: 120196212
• 负责人: Professor Dr. Martin S. Brandt
• 金额: --
• 依托单位: Walter Schottky Institut für physikalische Grundlagen der Halbleiterelektronik (WSI)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/120196212?language=en
• 关键词: Silicon; based; nanocomposites; thermoelectric; applications

The main goal of this project is the realization of efficient and sustainable silicon based thermoelectric materials. In this second funding period, the so called “nanoparticle in alloy” approach, theoretically proposed in the literature, forms a guide line. It combines the efficient scattering of phonons with short wavelengths on irregularly positioned atoms in common alloys with the efficient scattering of phonons with long wavelengths on larger structures, like nanoparticles. Metal silicide nanoparticles are considered for this purpose. Two coupled particle reactors, developed during the first funding period, allow for the realization of this concept. The concept includes also the approach of modulation doping, were small areas with very high doping concentrations alternate with areas of low doping concentration. This allows for electronic transport pathways without Coulomb scattering on charged dopants, while the clusters of dopants act as efficient centers for phonon scattering. For bulk samples, a current assisted sintering process has to be developed, in order to maintain the desired “nanoparticle in alloy”-structure and to prevent a general alloying of all components or a phase separation during sintering. For thin films, a multilayer approach will be used, where the laser annealing process will be combined with hydrogenation in DC plasmas or microwave heating. The thermal conductivity of the thin films will be measured with methods developed within this priority program by the Group of Prof. Völklein as well as with an optical non-contact method based on the mirage effect. In order to get a deeper insight into thermoelectric properties and structure forming processes, a 3D-Onsager network model will be developed, where input is taken from the molecular dynamic modelling of the microscopic processes during compaction.

该项目的主要目标是实现高效和可持续的硅基热电材料。在第二个资助期，所谓的“合金中的纳米颗粒”方法，理论上在文献中提出，形成了一个指导方针。它将短波声子在普通合金中不规则位置原子上的有效散射与长波声子在较大结构（如纳米粒子）上的有效散射结合起来。金属硅化物纳米颗粒被考虑用于此目的。在第一个资助期间开发的两个耦合粒子反应器使这一概念得以实现。该概念还包括调制掺杂的方法，即高掺杂浓度的小区域与低掺杂浓度的区域交替。这允许在带电掺杂剂上没有库仑散射的电子传输路径，而掺杂剂簇作为声子散射的有效中心。对于大块样品，必须开发一种电流辅助烧结工艺，以保持所需的“合金中的纳米颗粒”结构，并防止所有成分的普遍合金化或烧结过程中的相分离。对于薄膜，将使用多层方法，其中激光退火过程将与直流等离子体中的氢化或微波加热相结合。薄膜的热导率将由Völklein教授小组在该优先计划中开发的方法以及基于海市蜃楼效应的光学非接触方法进行测量。为了更深入地了解热电特性和结构形成过程，将开发3D-Onsager网络模型，其中输入来自压实过程中微观过程的分子动力学建模。