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.

拟议的项目集中于对机制的研究，这会影响金属氧化物中的塞贝克系数。在一个主要的部分中，它分析了粒度尺寸较小或等于膜厚度及其通过退火，气体环境和紫外线照明操作的纳米晶膜。单晶代表一种参考材料以及具有明确定义的几何形状的模型系统，可靠地确定材料参数和与气体环境的特定相互作用机制的分析。与散装材料相比，纳米结构膜具有高浓度的晶粒和晶界的优势。在具有固有表面积累的纳米结构半导体中，这些晶界降低了导热率，但在另一侧，增加了材料的电导率，对热电特性产生积极影响。这些特征是包含INN，INAS和IN2O3等几种含量的含量的内在特性。对于该项目，我们建议研究基于IN2O3作为热电，气体敏感材料的纳米晶体。通过粒径，掺杂和系统的操纵粒子表面的特异性变化，研究了颗粒，表面和晶界处的电子传输现象。主要的仪器将是通过特定的气体吸附来调整费米水平（工作函数）和表面带的弯曲。参考值将通过原位光电子光谱法获得。通过使用优化的纳米颗粒膜，这些效果将用于高度敏感的Seebeck气体传感器系统。一个主要目标是研究在纳米晶膜中观察到的现象。在特定膜中，塞贝克系数意外降低，而电阻增加。通过控制出现这种效果的条件，可以设计简单的传感器结构，以独立记录两个电气敏感参数。它可以提高商用金属氧化物气体传感器在特定气体上的选择性方面的性能，并能够实施自校准方案，从而显着延长传感器设备的使用寿命。