Tuning of the thermoelectric properties of Inx(M)2-xO3-nanoparticles

该项目的重点是开发一个模型系统，用于设计纳米级热电器件，并尽可能独立地故意改变电，热和热电性能，并评估传感器设备中的应用。在优先计划的第二阶段：“纳米结构热电”，我们将开发的氧化铟基材料基础扩展为纳米颗粒和纳米复合薄膜作为热电材料纳米结构薄膜与块状材料相比，具有高浓度晶粒和晶界的优势。在具有载流子的固有表面积累的纳米结构半导体中，这些晶界降低了热导率，但另一方面，增加了材料的电导率，对热电性能产生了积极影响。这些特性是几种含铟化合物如InN、InAs和In 2 O3的固有特性。在这个项目中，我们提出了InxM 2-xO 3纳米颗粒（M=Zn，Ga，Ni，Ti）用作热电材料。第二阶段的主要目标是通过改变颗粒尺寸和系统地操纵颗粒表面性质来调节纳米颗粒中的电导率和声子热导率。主要的手段将是费米能级（功函数）的调整和特定气体吸附的表面能带弯曲。参考值将通过原位光电子能谱法获得。实验研究将得到SPP内合作伙伴的进一步测量以及导热性和导电性的集合蒙特卡罗模拟的支持。在未来，通过使用优化的纳米颗粒薄膜，这些效应将用于自供电或高灵敏度的塞贝克气体传感器系统。

The proposed project is focused on the development of a model system for the design of nanoscale thermoelectrics, and the intentional variation of electrical, thermal and thermoelectrical properties as far as possible independently of each other and the evaluation of theapplications in sensor devices. In this second period within the Priority Program: “Nanostructured thermoelectrica”, we extend the developed indium oxide based material basis for nanoparticle and nanocomposite films as thermoelectric materials Nanostructured films, in comparison to the bulk materials, have the advantage of possessing a high concentration of grains and grain boundaries. In a nanostructured semiconductor with intrinsic surface accumulation of carriers, these grain boundaries lower the thermal conductivity but on the other side, increase the electrical conductivity of the material with a positive impact on the thermoelectric properties. These characteristics are intrinsic properties for several indium containing compounds such as InN, InAs, and In2O3. In this project, we propose InxM2-xO3 nanoparticles (M=Zn, Ga, Ni, Ti) to be used as thermoelectric material. The main goal in the second period is to tune the electrical conductivity and the phonon thermal conductivity in nanoparticles by variation of the particle size and systematic manipulation of the particle surface properties. The major instrument will be the adjustment of the Fermi level (work function) and the surface band bending by specific gas adsorption. The reference values will be obtained by in situ photoelectron spectroscopy. Experimental investigations will be supported by further measurements by partners within the SPP as well as by ensemble Monte- Carlo simulations for thermal and electric conductivity. In future, by using optimized nanoparticle films, these effects will be used for self-powered or highly-sensitive Seebeck gas sensor systems.