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Nano Materials Science 2023年第4期5卷 439-446页

作者： Zilian Qi Tianwei Zhang Xiao-Dong Zhang Qing Xu Kun Cao Rong Chen State Key Laboratory of Digital Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyHubei430074China State Key Laboratory of Materials Processing and Die&Mold Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyHubei430074China

The flexible pressure sensor has been credited for leading performance including higher sensitivity,faster response/recovery,wider detection range and higher mechanical durability,thus driving the development of novel sensing materials enabled by new processing technologies.Using atomic layer infiltration,Pt nanocrystals with dimensions on the order of a few nanometers can be infiltrated into the compressible lamellar structure of Ti3C2Tx MXene,allowing a modulation of its interlayer spacing,electrical conductivity and piezoresistive property.The flexible piezoresistive sensor is further developed from the Pt-infiltrated MXene on a paper substrate.It is demonstrated that Pt infiltration leads to a significant enhancement of the pressure-sensing performance of the sensor,including increase of sensitivity from 0.08 kPa^(-1)to 0.5 kPa^(-1),extension of detection limit from 5 kPa to 9 kPa,decrease of response time from 200 ms to 20 ms,and reduction of recovery time from 230 ms to 50 ms.The mechanical durability of the flexible sensor is also improved,with the piezoresistive performance stable over 1000 cycles of flexure fatigue.The atomic layer infiltration process offers new possibilities for the structure modification of MXene for advanced sensor applications.

关键词： MXene Atomic layer deposition Pt infiltration piezoresistive Flexible pressure sensor

piezoresistive effect in p-type polycrystalline diamond films

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Science China Mathematics 1999年第7期42卷 769-777页

作者：方亮王万录廖克俊丁培道王健 Department of Applied Physics College of Science Chongqing University Chongqing China Department of Material Science College of Material Science & Engineering Chongqing China

The piezoresistive effect of boron-doped polycrystalline diamond films was analyzed and discussed by the famous M-S polycrystalline model. It is found that the valence bands splitting-off and the grain-boundary scattering are the main factors responsible for the piezoresistive effect in the p-type polycrystalline diamond films. The gauge-factor calculation formula including the effect of both background scattering and grain-boundary scattering were obtained, and the calculation results are in accordance with the experimental results.

关键词： diamond films piezoresistive effect grain-boundary scattering valence bands split-off.

Flexible Waterproof piezoresistive Pressure Sensors with Wide Linear Working Range Based on Conductive Fabrics

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Nano-Micro Letters 2020年第11期12卷 229-241页

作者： Hongcheng Xu Libo Gao Yuejiao Wang Ke Cao Xinkang Hu Liang Wang Meng Mu Min Liu Haiyan Zhang Weidong Wang Yang Lu School of Mechano‑Electronic Engineering Xidian UniversityXi’an 710071People’s Republic of China CityU-Xidian Joint Laboratory of Micro/Nano-Manufacturing Xi’an 710071People’s Republic of China Department of Mechanical Engineering City University of Hong KongKowloon 999077Hong Kong SARPeople’s Republic of China Nano‑Manufacturing Laboratory(NML) Shenzhen Research Institute of City University of Hong KongShenzhen 518057People’s Republic of China Micro‑/Nano‑technology Research Center State Key Laboratory for Manufacturing Systems EngineeringXi’an Jiaotong UniversityXi’an 710049People’s Republic of China

Developing flexible sensors with high working performance holds intense interest for diverse applications in leveraging the Internet-of-things(IoT)infrastructures.For flexible piezoresistive sensors,traditionally most efforts are focused on tailoring the sensing materials to enhance the contact resistance variation for improving the sensitivity and working range,and it,however,remains challenging to simultaneously achieve flexible sensor with a linear working range over a high-pressure region(>100 kPa)and keep a reliable sensitivity.Herein,we devised a laserengraved silver-coated fabric as"soft"sensor electrode material to markedly advance the flexible sensor's linear working range to a level of 800 kPa with a high sensitivity of 6.4 kPa^-1 yet a fast response time of only 4 ms as well as long-time durability,which was rarely reported before.The integrated sensor successfully routed the wireless signal of pulse rate to the portable smartphone,further demonstrating its potential as a reliable electronic.Along with the rationally building the electrode instead of merely focusing on sensing materials capable of significantly improving the sensor's performance,we expect that this design concept and sensor system could potentially pave the way for developing more advanced wearable electronics in the future.

关键词： Flexible sensor piezoresistive Graphite flakes Laser engraving Silver fabrics

An integrated MEMS piezoresistive tri-axis accelerometer

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Journal of Semiconductors 2013年第10期34卷 76-82页

作者：张永平何常德于佳琪杜春晖张娟婷丑修建张文栋 Key Laboratory of Instrumentation&Science Dynamic Measurement Ministry of EducationNorth University of China Key Laboratory of Science Technology on Electronic Test&Measurement North University of China

An integrated MEMS accelerometer has been designed and fabricated. The device, which is based on the piezoresistive effect, accomplishes the detection of three components of acceleration by using piezoresistors to compose three Wheatstone bridges that are sensitive to the only given orientation. The fabrication of the accelerometer is described, and the theory behind its operation developed. Experimental results on sensitivity, crossaxis-coupling degree, and linearity are presented. The sensitivity of X, Y and Z were 5.49 mV/g, 5.12 mV/g and 4.82 mV/g, respectively; the nonlinearity of X, Y and Z were 0.01%, 0.04% and 0.01%, respectively; the crossaxis-coupling factor of X axis to Y axis and Z axis are 0.119% and 2.26%; the cross-axis-coupling factor of Y axis to X axis and Z axis are 0.157% and 4.12%; the cross-axis-coupling factor of Z axis to X axis and Y axis are 0.511% and 0.938%. The measured performance indexes attain accurate vector-detection in practical applications, and even at a navigation level. In conclusion, the accelerometer is a highly integrated sensor.

关键词： accelerometer integration piezoresistive tri-axis MEMS

Design and measurement of a piezoresistive ultrasonic sensor based on MEMS

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Journal of Semiconductors 2013年第7期34卷 116-122页

作者：于佳琪何常德宛克敬廉德钦薛晨阳张文栋 Key Laboratory of Instrumentation Science&Dynamic Measurement Ministry of EducationNorth University of China Key Laboratory of Science and Technology on Electronic Test & Measurement North University of China

A kind of piezoresistive ultrasonic sensor based on MEMS is proposed,which is composed of a membrane and two side beams.A simplified mathematical model has been established to analyze the mechanical properties of the sensor.On the basis of the theoretical analysis,the structural size and layout location of the piezoresistors are determined by simulation analysis.The boron-implanted piezoresistors located on membrane and side beams form a Wheatstone bridge to detect acoustic signal.The membrane-beam microstructure is fabricated integrally by MEMS manufacturing technology.Finally,this paper presents the experimental characterization of the ultrasonic sensor,validating the theoretical model used and the simulated model.The sensitivity reaches -116.2 dB（0 dB reference = 1 V/μbar,31 kHz）,resonant frequency is 39.6 kHz,direction angle is 55°.

关键词： MEMS piezoresistive ultrasonic sensor ANSYS membrane-beams

Design and measurement of a piezoresistive triaxial accelerometer based on MEMS technology

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Journal of Semiconductors 2012年第10期33卷 48-52页

作者：杜春晖何常德于佳琪葛晓洋张永平张文栋 Key Laboratory of Instrumentation Science&Dynamic Measurement Ministry of EducationNorth University of China Key Laboratory of Science and Technology on Electronic Test&Measurement North University of China Key Laboratory of Science and Technology on Electronic Test&Measurement

With the springing up of the MEMS industry,research on accelerometers is focused on miniaturization, integration,high reliability,and high resolution,and shares extensive application prospects in military and civil fields.Comparing with the traditional single cantilever beam structure or ＂cantilever-mass＂ structure,the proposed structure of ＂8-beams/mass＂ with its varistor completely symmetric distribution in micro-silicon piezoresistive triaxial accelerometer in this paper has a higher axial sensitivity and smaller cross-axis sensitivity.Adopting ANSYS, the process of structural analysis and the manufacturing flow of sensing unit are showed.In dynamic testing conditions, it can be concluded that the axial sensitivity of x,y,and z are Sx-48μV/g,Sy = 54μV/g and Sz = 217μV/g respectively,and the nonlinearities are 0.4%,0.6%and 0.4%.

关键词： cross-axis sensitivity piezoresistive symmetric distribution triaxial accelerometer

The design and test of MEMS piezoresistive ultrasonic sensor arrays

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Journal of Semiconductors 2013年第3期34卷 51-57页

作者：廉德钦何常德张慧于佳琪宛克敬薛晨阳 Key Laboratory of Instrumentation Science&Dynamic Measurement Ministry of EducationNorth University of China Key Laboratory of Science and Technology on Electronic Test&Measurement North University of China Key Laboratory of Science and Technology on Electronic Test & Measurement North University of China

The design,fabrication and packaging of a type of MEMS piezoresistive ultrasonic transducer array are introduced.The consistency of the resonance frequency and the sensitivity of the array are tested.Moreover,we detect the directivity and the multi-target identification ability of the array.The results of the consistency of the resonance frequency and the sensitivity show that there is a gap between the practical and theoretical results.This paper analyzes this problem in detail and points out the direction of improvement.As for the directivity,the actual result is consistent with the theoretical one.The results of multiple target distinguishing tests demonstrate that the smallest resolution angle of the array is 5.72°when the distance between the sensor array and measured objects is 2 m.

关键词： ultrasonic sensor piezoresistive integrated array multi-target identification

Soft piezoresistive pressure sensing matrix from copper nanowires composite aerogel

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Science Bulletin 2016年第20期61卷 1624-1630页

作者： Lim Wei Yap Shu Gong Yue Tang Yonggang Zhu Wenlong Cheng Department of Chemical Engineering Monash UniversityClayton VIC 3800 Australia Melbourne Centre for Nanofabrication Clayton VIC 3168Australia CSIRO Manufacturing Flagship Clayton VIC 3168 Australia

We report on a simple yet efficient approach to fabricate soft piezoresistive pressure sensors using copper nanowires-based aerogels.The sensors exhibit excellent sensitivity and durability and can be easily scalable to form large-area sensing matrix for pressure mapping.This opens a low-cost strategy to wearable biomedical sensors.

关键词： Copper nanowires Aerogel piezoresistive Pressure sensing matrix

The dual cycle bridge detection of piezoresistive triaxial accelerometer based on MEMS technology

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Journal of Semiconductors 2014年第6期35卷 80-89页

作者：张娟婷何常德张慧李玉平张永平杜春晖张文栋 Key Laboratory of Instrumentation Science & Dynamic Measurement Ministry of EducationNorth University of China Key Laboratory of Science and Technology on Electronic Test & Measurement North University of China

A cycle bridge detection method, which uses a piezoresistive triaxial accelerometer, has been described innovatively. This method just uses eight resistors to form a cycle detection bridge, which can detect the signal of the three directions for real time. It breaks the law of the ordinary independent Wheatstone bridge detection method, which uses at least 12 resistors and each four resistors connected as a Wheatstone bridge to detect the output signal from a specific direction. In order to verify the feasibility of this method, the modeling and simulating of the sensor structure have been conducted by ANSYS, then the dual cycle bridge detection method and independent Wheatstone bridge detection method are compared, the result shows that the former method can improve the sensitivity of the sensor effectively. The sensitivity of the x, y-axis used in the former method is two times that of the sensor used in the latter method, and the sensitivity of the z-axis is four times. At the same time, it can also reduce the cross-axis coupling degree of the sensor used in the dual cycle bridge detection method. In addition, a signal amplifier circuit and adder circuit have been provided, Finally, the test result of the ＂eight-beams/mass＂ triaxial accelerometer, which is based on the dual cycle bridge detection method and the related circuits, have been provided. The results of the test and the theoretical analysis are consistent, on the whole.

关键词： piezoresistive triaxial accelerometer cycle detection bridge MEMS

A piezoresistive Sensor for Measuring Tongue Pressure

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Chinese Journal of Electronics 2016年第1期25卷 77-80页

作者： WANG Shaojie FENG Yongjian CHEN Yifei ZHANG Rong HUANG Yuanqing Department of Mechanical and Electrical Engineering Xiamen University

Dysphagia is common after a cerebral vascular accident(or stroke), and it seriously affects the prognosis. Timely diagnosis in clinical, scientific assessment of dysphagia and correct treatment given to patients are essential. This study is aimed to develop a sensor for measuring tongue pressure during swallowing or other times,and to help doctors make a scientific assessment of dysphagia grade. It is a kind of miniaturization of piezoresistive pressure sensor with an outer diameter of 10 mm and a thickness of 3mm. A calibration and data acquisition ARM system is designed, which can continuously record tongue pressure in 8 hours. The sensor has a detection range from0 to 30 k Pa, and the measurement error can be controlled in 5%.

关键词： piezoresistive Sensor Tongue pressure Resistance strain chip