面向栽培基质的二氧化钛电极EGFET pH传感器设计

Design of titanium dioxide electrode EGFET pH sensor for cultivated substrate

针对农业生产中栽培基质直接在线检测pH准确性差的问题,采用化学腐蚀法,制备出具有氢离子敏感特性和超亲水特性的二氧化钛(TiO_(2))电极,并且采用退火工艺以提高电极表面硬度;将TiO_(2)电极与金属氧化物场效应晶体管(MOSFET)组合成基于延伸式栅极场效应晶体管(EGFET)的pH传感器.测试得到传感器灵敏度为0.05063 V/pH,重复性试验的变异系数最大为0.0057.测试结果表明该传感器具有良好的灵敏度、重复性和稳定性.选取4种典型栽培基质进行pH在线检测应用试验,pH检测误差的绝对值最大为0.18,经过温度补偿后误差的绝对值最大为0.11;使用后电极表面的亲水性依旧保持良好.应用试验结果表明,该传感器适用于栽培基质pH在线检测.

In order to solve the problem of poor accuracy of direct online pH detection of cultivation substrate in agricultural production,a titanium dioxide(TiO_(2))electrode with hydrogen ion sensitivity characteristics and super hydrophilicity characteristics was prepared by using chemical corrosion method,and annealing process was used to improve the surface hardness of the electrode.TiO_(2) electrodes and metal-oxide semiconductor field-effect transistor(MOSFET)were combined to form a pH sensor based on extended gate field effect transistor(EGFET).The sensitivity of the sensor was tested to be 0.05063 V/pH,and the maximum coefficient of variation of in the repeatability test was 0.0057.The test results show that the sensor has good sensitivity,repeatability and stability.Four typical cultivation substrates are selected for online pH application experiments.The maximum absolute value of pH test error is 0.18,and the maximum absolute value of pH test error is 0.11 after temperature compensation.The hydrophilicity of the electrode surface remains good after use.The application test results show that the sensor is suitable for online detection of pH in cultivation substrates.