Research On The Parameters Control In The Fabrication Of The W-Pt Micro-nano Thermocouple

Single Cell Analysis has become increasingly popular over recent years.Single cells,as the basic components of most living organisms,contain all the genetic information of the corresponding species.Analysis in single cells avoids the interference of cell heterogeneity,resulting in higher accuracies and helping restore biological events.Numerous biological events,such as embryonic development and tumor formation and metastasis,start from single cells.Such fact makes Single Cell Analysis a more reasonable choice compared with studying physiological tissues in certain scenarios.Temperature,as an important liveness indicator of living organisms,often requires to be carefully measured in Single Cell Analysis.Currently available measurement methods include fluorescent staining and quantum dots.Despite being widely used,these approaches,however,still lack the capability of real-time measurements with high precisions.As a widely-used type of temperature sensors,thermocouples have multiple desirable properties,including the ability of real-time quantitative measurement,remaining operational in wide temperature ranges,and high measurement precisions.They have been popularly used in both life and production environments.By using thermocouples,we are able to conveniently obtain the temperature values by measuring the voltages.Wang et al.proposed a W-Pt thermocouple using micro/nano scales to solve the aforementioned shortcomings of existing temperature measurement approaches.However,the coaxial thermocouples prepared by this method have different characteristics from those of the thermocouples prepared in macroscopic scales: the thermocouple's thermoelectric coefficient does not solely depend on its materials.Even with the same film thickness and wire diameter,large differences can be observed in thermoelectric coefficients across different W-Pt Micro-nano Thermocouples.As can be seen,thermoelectric properties of the metal heterojunction in micro/nano scales not only depend on the types of metal materials as well as their scales but also are influenced by metal heterojunction morphology parameters.Through the exploration of the W-Pt metal heterojunction in micro/nano scales,we can have a better understanding of the physical properties of the materials in sub-micron scales,which are of great significance.Moreover,we can better handle the properties of W-Pt Micro-nano Thermocouples,thus the sensitivity and stability of such sensors can be improved.Finally,we can find the balancing point between the temperature measurement heterojunction scale and sensitivity,which helps provide a powerful and reliable tool for intracelluar temperature measurements.In this paper,the relationship between the morphology and the thermoelectric coefficient of W-Pt metal heterojunction at micro/nano scale is investigated based on W-Pt micro-nano thermocouple.First,it is necessary to control the morphology of the W-Pt micro-nano thermocouple's metal heterojunction.In this paper,a new double feedback method for electrochemical fabrication control strategy is proposed.This strategy can control the drop-off delay time during the tip's formation.By extending the double feedback method,it can not only control the electrochemical reaction's on-off,but the depth,of which the tungsten bar placed into the corrosive solution,is totally under control.Based on the double feedback control strategy,we realize the W-Pt Micro-nano thermocouple front-end automatic fabrication system,which achieves the purpose of morphology control.Secondly,it is necessary to obtain the thermoelectric coefficient of the W-Pt Micro-nano thermocouple's metal heterojunction.In this paper,the W-Pt Micro-nano thermocouple automatic calibration system is designed by the combination with constant temperature water bath and zero-degree thermostat.It can simultaneously calibrate multiple W-Pt Micro-nano thermocouples with great precision,which greatly improves the efficiency.Finally,based on these two systems,W-Pt metal heterojunctions with different morphologies were prepared and their thermoelectric properties were obtained.The relationship between the morphology and the thermoelectric coefficient of W-Pt metal heterojunction at micro/nano scale was obtained based on statistical methods.The two systems designed in this thesis provide a powerful tool for intracelluar temperature measurement.The study of the morphology and the thermoelectric coefficient of W-Pt metal heterojunction provides a follow-up to the improvement of W-Pt micro-nano thermocouple's properties.