Research On Mechanism And Performance Optimization Of Field-Assisted Thermal Ionization TiO₂ Nanotube Temperature Sensor

Sensors,the "frontier post" of the control system,are key components to capture information.The ionization sensor has the characteristics of fast response and high sensitivity,so it is expected to detect the basic detection parameter temperature of the sensor quickly and accurately.This paper analyzes the internal working mechanism and temperature sensitivity characteristics of the ionization temperature sensor in the micro-gap-nano-tip field through simulation calculations;and the paper combines experiments to verify it.According to the small existing problems of output signal,this paper mainly starts from changing the two aspects,materials and morphology,to have a optimizing study.The main research contents of this paper are as follows:(1)Firsty,a two-dimensional space discharge model of the N2-O₂ mixed gas in the atmosphere in the micro-nano-tip field under normal temperature and pressure is established in this paper,and the internal working mechanism of the sensor is studied;Secondly,the simulation study of the discharge of the sensor(293.15 K-373.15 K)at different temperatures is carried out.The results show that the discharge current density of the sensor increases exponentially with the increase of temperature,and its maximum temperature coefficient is 3.43×10-2 K-1.(2)The TiO₂ nanotube array prepared by anodizing method is used as the cathode material to construct the sensor,and the discharge experiment at different temperatures is carried out in vacuum and air respectively.The experimental results show that:in vacuum,the electron emission characteristics of the sensor conform to the classic field-assisted thermionic emission theory;in the air,the discharge current of the sensor has a single-value corresponding relationship with the ambient temperature,and its change trend is consistent with the simulation results,that is,with the increase of temperature,the discharge current increases exponentially,and its maximum temperature coefficient is 3.89×10-2 K-1.At the same time,the reliability of the simulation model is further verified.(3)In this paper,the output performance of the sensor is optimized from different angles.One is to change the material of the nano-electrode,that is,to prepare Mn-doped nanotube,which can improve the emission performance by reducing the work function required for electron emission.The experimental results show that the output current of the sensor increases after doping,and the maximum temperature coefficient is increased to 4.35×10-2 K-1;Secondly,to change the morphology of nano-electrode,that is,explore the best tube spacing of nano-electrode.The simulation results show that there is an optimal relationship between the nanotubes spacing and the tube length,so that the shielding effect and the effective emission area are optimally coupled,which makes the discharge intensity maximum,and then the discharge current can be improved.In this paper,the simulation and experiment are combined to study the internal mechanism and optimize the performance of the ionization temperature sensor from the microscopic and macroscopic angles,which has guiding significance for the development of this kind of sensor.