| New technological revolution has led the world into information age. With the rapid development of the society, Internet has been required to develop into a new systemIoT(internet of things). To realize this purpose in which objects would have information interchange and communication, different kinds of sensors are needed in many fields such as modernized production process, detection system and control system. Sensor is the major part of information collection system and the main links between modernized measurement and automatic control process. Sensors could transfer one kind of signal into another kind of signal.Different background and different situation needs different kinds of sensors.Sensors would be classified by testing target, measurement principle, sensitive material and so on. In this work, n-type semiconductor nanomaterial is used to be sensitive material in sensors, in which non-electrical signal was traduced into electrical signal. The sensors were applied in humidity, gas, and bio sensing. Surface adsorption effect is used to explain the sensing process.The main research concludes in this thesis are as following:1. Humidity sensing properties of a single Sb doped SnO2 nanowire field effect Transistor: Based on the method of photo lithography and radio frequency magnetron sputtering, SnO2:Sb single nanowire transistor on highly doped silicon substrate with superior properties was fabricated under room temperature, it shows good typical transfer and output characteristic. While the temperature is constant kept at 25 °C,the threshold voltage changes from-11.2 V to-14.6 V while the relative humidity changes from 22% to 40% with the step of 6%. The humidity sensor shows well stability and repeatability after one month. To our knowledge, it is the first time utilizing transfer characteristics of single tin oxide nanowire transistor in humidity sensing field.2. High-performance humidity sensors from Ni(SO4)0.3(OH)1.4 nanobelts: To have a explore in methods of humidity sensor fabrication, a facile method is utilized.Ni(SO4)0.3(OH)1.4 nanobelts were coated onto interdigital gold electrodes which is sputtered on a ceramic substrate. The humidity sensing properties prove that the nanowire thin-film device owns a high sensitivity, good stability, and fast response,and good repeatability after three month later. And also, the sensor works well underdifferent temperatures. When temperature is increased into 40, 50, 60, 70, 80, 90 °C,the sensors work well.3. High-performance acetone sensor based on SnO2 and SnO2:Sb nanowires: SnO2 and SnO2:Sb nanowires were grinded and coated on alumina ceramic tube with Pt wires on, heating coil is crossed the tube. Voltages applied on heating coil would change the working temperature of the sensors. After the sensors were fabricated,aging for 48 hours were performed. During the sensing test to kinds of gases, the sensor based on SnO2:Sb nanowire show a higher sensitivity and faster response and recovery time. One-dimensional nanowires has potential in gas sensing, and doping would improve the gas sensing properties obviously.4. Indium-tin-oxide thin film transistor bio-sensors for label-free detection of avian influenza virus H5N1: We fabricated ITO thin film transistor on glass substrate.Firstly, we immobilized the anti-H5N1 antibodies on ITO channel by trimethoxysilane,while H5N1 virus were infected onto the ITO channel, the combination between the antibody and virus would influence the carriers in the surface of ITO channel, which would be detected by transfer curves. By utilizing the change of transfer characteristics, the ITO FET showed good sensing performance includifferential selection, low detection limit, good repeatability and stability.
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