全介观尺度放电体系中的临界现象及其气敏效应研究

项目名称： 全介观尺度放电体系中的临界现象及其气敏效应研究

项目编号： No.61504079

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 无线电电子学、电信技术

项目作者： 刘海

作者单位： 上海交通大学

项目金额： 22万元

中文摘要： 放电体系结构的尺度效应是气体电子学和等离子体物理领域的一个重大命题，本项目提出全介观尺度放电体系，在自由空气中粒子平均自由程尺度上调制电荷分离和输运过程，围绕临界效应的现象学表征和理论阐释，从尺度效应的角度研究等离子体演化过程与电极系统结构要素之间相关性，揭示气体电子学现象经典理论描述的尺度条件，在气体电子学和等离子体物理研究中提出了新的科学命题；研究通过电极间隙和放电电极在介观尺度水平上的结构特性抑制自由空气中的失稳随机过程，揭示低电离碰撞频率稠密系统中临界效应的可控机理，这是在常压空气中，探索构建特性可控气体放电体系的一个新的尝试；研究通过构建全介观尺度电极系统得到一种超低压放电体系，基于纳米尺度温区的变化调制电子平均自由程和中性气体分子热运动速率，构建分子水平的动力学特性与放电临界效应的相互关系，从而能在单一器件结构中得到相同气体成分的不同气敏信号，提供一种提高离化传感选择性的方法。

中文关键词： 气体传感器；离化式气体传感器；微机电系统；介观尺度

英文摘要： The scale effect in a discharge system is a crucial issue in the research field of gaseous electronics and plasma physics. In this project, we propose the concept of “all-mesoscale discharge system” (AMDS), which modulates the procedures of charges separation and transportation at the level of the gas particles’ mean free path in the normal pressure and temperature. Focusing on the description of the critical phenomenon and interpretation of theory, this project studies the correlation between the plasma evolution and the structural factors of the electrodes system in the perspective of scale effect, in order to reveal the scale requirements for a discharge system to be determined by the classical theories, which brings about a creative scientific issue in gaseous electronics and plasma physics. The mesoscale electrodes gap and electrode structural characteristics in AMDS result in the suppressive effect on the unstable random procedures, which presents the control mechanism of the critical effect in a dense system with low-frequency ionization collisions. This is an exploratory attempt to build a gas discharge system in the normal pressure where the features can be well controlled. A novel discharge system with an ultralow working voltage can be obtained based on the study of AMDS, meanwhile the mean free path of electrons and the frequency of neutral gas molecules’ thermal motion can be modulated by the adjustment of the nanoscale thermal region. Then the correlation between the molecular dynamic characteristics and the discharge critical effect is established, which provides a route for a unique gas sensing structure to capture different sensing signals from a certain component at the same time, in order to significantly improve the selectivity of an ionization gas sensor.

英文关键词： gas sensor;ionization gas sensor;MEMS;mesoscope