Seebeck gas sensors

塞贝克气体传感器

• 批准号: 252183801
• 负责人: Professor Dr. Oliver Ambacher
• 金额: --
• 依托单位: Fraunhofer-Institut für Angewandte Festkörperphysik (IAF)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/252183801?language=en
• 关键词: Seebeck; gas; sensors

The proposed project in focused on the investigation of the mechanisms, which affect the Seebeck coefficient in metal oxides. To a major part, it analyses nanocrystalline films with a particle size smaller or equal to the film thickness and their manipulation by annealing, gas environment and ultraviolet illumination. Single crystalline represents a reference material as well as a model system with well-defined geometry for reliable determination of materials parameter and the analysis of specific interaction mechanisms with a gas environment. 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. For the project we propose to investigate nanocrystalline based on In2O3 as thermoelectric, gas sensitive material. The electronic transport phenomena in the particles, at the surface and at grain boundaries, which contribute to the gas detection phenomena, are investigated by specific variation of particle size, doping and systematic manipulation of the particle surfaces. 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.By using optimized nanoparticle films, these effects will be used for highly-sensitive Seebeck gas sensor systems. A major goal will be the investigation of a phenomenon that has been observed in nanocrystalline films. In specific film the Seebeck coefficient unexpectedly decreased while the electric resistance increased. By controlling the conditions where this effect appears, simple sensor structures can be designed which record two electric, gas sensitive parameters independently. It enables to improve the performance of commercial metal oxide gas sensors regarding selectivity on specific gases and enable the implementation of self-calibration schemes, which would prolong the service life of sensor devices remarkably.

该项目的重点是研究影响金属氧化物塞贝克系数的机制。主要分析了纳米晶薄膜的制备，以及退火、气体环境和紫外光对纳米晶薄膜的影响。单晶代表了一种参考材料以及具有明确几何形状的模型系统，用于可靠地确定材料参数和分析与气体环境的特定相互作用机制。纳米结构膜与块体材料相比，具有具有高浓度的晶粒和晶界的优点。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In2O3的固有特性。在本计画中，我们提出以In_2O_3为基础之奈米晶材料作为热电、气敏材料。粒子中的电子输运现象，在表面和在晶界，这有助于气体检测现象，研究通过特定的变化的颗粒尺寸，掺杂和系统的操纵的颗粒表面。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。通过使用优化的纳米颗粒薄膜，这些效应将用于高灵敏度的塞贝克气体传感器系统。一个主要的目标将是在纳米晶薄膜中观察到的现象的调查。在特定的薄膜中，塞贝克系数出乎意料地降低，而电阻增加。通过控制这种效应出现的条件，可以设计简单的传感器结构，其独立地记录两个电、气敏参数。它能够提高商用金属氧化物气体传感器在特定气体选择性方面的性能，并能够实现自校准方案，这将显著延长传感器设备的使用寿命。