Silicon micro-levers and a multilayer graphene membrane studied via laser photoacoustic detection

Abstract. Laser photoacoustic spectroscopy (PAS) is a method that utilizes the sensing of the pressure waves that emerge upon the absorption of radiation by absorbing species. The use of the conventional electret microphone as a pressure sensor has already reached its limit, and a new type of microphone – an optical microphone – has been suggested to increase the sensitivity of this method. The movement of a micro-lever or a membrane is sensed via a reflected beam of light, which falls onto a position-sensing detector. The use of one micro-lever as a pressure sensor in the form of a silicon cantilever has already enhanced the sensitivity of laser PAS. Herein, we test two types of home-made sensing elements – four coupled silicon micro-levers and a multilayer graphene membrane – which have the potential to enhance this sensitivity further. Graphene sheets possess outstanding electromechanical properties and demonstrate impressive sensitivity as mass detectors. Their mechanical properties make them suitable for use as micro-/nano-levers or membranes, which could function as extremely sensitive pressure sensors. Graphene sheets were prepared from multilayer graphene through the micromechanical cleavage of basal plane highly ordered pyrolytic graphite. Multilayer graphene sheets (thickness ∼102 nm) were then mounted on an additional glass window in a cuvette for PAS. The movements of the sheets induced by acoustic waves were measured using an He–Ne laser beam reflected from the sheets onto a quadrant detector. A discretely tunable CO2 laser was used as the source of radiation energy for the laser PAS experiments. Sensitivity testing of the investigated sensing elements was performed with the aid of concentration standards and a mixing arrangement in a flow regime. The combination of sensitive microphones and micromechanical/nanomechanical elements with laser techniques offers a method for the study and development of new, reliable and highly sensitive chemical sensing systems. To our knowledge, we have produced the first demonstration of the feasibility of using four coupled silicon micro-levers and graphene membranes in an optical microphone for PAS. Although the sensitivity thus far remains inferior to that of the commercial electret microphone (with an S / N ratio that is 5 times lower), further improvement is expected to be achieved by adjusting the micro-levers and membrane elements, the photoacoustic system and the position detector.

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Development of circuit solution and design of capacitive pressure sensor array for applied robotics

Robotics and Technical Cybernetics ◽

10.31776/rtcj.8406 ◽

2020 ◽

Vol 8 (4) ◽

pp. 296-307

Author(s):

Konstantin Krestovnikov ◽

Aleksei Erashov ◽

Аleksandr Bykov

Keyword(s):

Pressure Sensor ◽

Output Signal ◽

Sensor Array ◽

Applied Pressure ◽

Pressure Sensors ◽

Fine Tuning ◽

Capacitive Pressure Sensor ◽

Cell Parameters ◽

Linear Pattern ◽

Sensor Structure

This paper presents development of pressure sensor array with capacitance-type unit sensors, with scalable number of cells. Different assemblies of unit pressure sensors and their arrays were considered, their characteristics and fabrication methods were investigated. The structure of primary pressure transducer (PPT) array was presented; its operating principle of array was illustrated, calculated reference ratios were derived. The interface circuit, allowing to transform the changes in the primary transducer capacitance into voltage level variations, was proposed. A prototype sensor was implemented; the dependency of output signal power from the applied force was empirically obtained. In the range under 30 N it exhibited a linear pattern. The sensitivity of the array cells to the applied pressure is in the range 134.56..160.35. The measured drift of the output signals from the array cells after 10,000 loading cycles was 1.39%. For developed prototype of the pressure sensor array, based on the experimental data, the average signal-to-noise ratio over the cells was calculated, and equaled 63.47 dB. The proposed prototype was fabricated of easily available materials. It is relatively inexpensive and requires no fine-tuning of each individual cell. Capacitance-type operation type, compared to piezoresistive one, ensures greater stability of the output signal. The scalability and adjustability of cell parameters are achieved with layered sensor structure. The pressure sensor array, presented in this paper, can be utilized in various robotic systems.

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Simulation and Nonlinearity Optimization of a High-Pressure Sensor

Sensors ◽

10.3390/s20164419 ◽

2020 ◽

Vol 20 (16) ◽

pp. 4419

Author(s):

Ting Li ◽

Haiping Shang ◽

Weibing Wang

Keyword(s):

High Pressure ◽

Pressure Sensor ◽

Pressure Sensors ◽

Original Model ◽

Ansys Software ◽

Nonlinear Error ◽

Sensor Model ◽

Optimized Model ◽

Simulation Results ◽

Better Than

A pressure sensor in the range of 0–120 MPa with a square diaphragm was designed and fabricated, which was isolated by the oil-filled package. The nonlinearity of the device without circuit compensation is better than 0.4%, and the accuracy is 0.43%. This sensor model was simulated by ANSYS software. Based on this model, we simulated the output voltage and nonlinearity when piezoresistors locations change. The simulation results showed that as the stress of the longitudinal resistor (RL) was increased compared to the transverse resistor (RT), the nonlinear error of the pressure sensor would first decrease to about 0 and then increase. The theoretical calculation and mathematical fitting were given to this phenomenon. Based on this discovery, a method for optimizing the nonlinearity of high-pressure sensors while ensuring the maximum sensitivity was proposed. In the simulation, the output of the optimized model had a significant improvement over the original model, and the nonlinear error significantly decreased from 0.106% to 0.0000713%.

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Enhanced piezocapacitive response in zinc oxide tetrapod–poly(dimethylsiloxane) composite dielectric layer for flexible and ultrasensitive pressure sensor

Nanoscale ◽

10.1039/d0nr06743a ◽

2021 ◽

Vol 13 (12) ◽

pp. 6076-6086

Author(s):

Gen-Wen Hsieh ◽

Shih-Rong Ling ◽

Fan-Ting Hung ◽

Pei-Hsiu Kao ◽

Jian-Bin Liu

Keyword(s):

Zinc Oxide ◽

Pressure Sensor ◽

Dielectric Layer ◽

Pressure Sensors ◽

Dielectric Matrix ◽

First Time

Zinc oxide tetrapod is introduced for the first time within a poly(dimethylsiloxane) dielectric matrix for the formation of ultrasensitive piezocapacitive pressure sensors.

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CMOS-MEMS Based Current Mirror MOSFET Embedded Pressure Sensor for Healthcare and Biomedical Applications

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.647.315 ◽

2013 ◽

Vol 647 ◽

pp. 315-320 ◽

Cited By ~ 6

Author(s):

Pradeep Kumar Rathore ◽

Brishbhan Singh Panwar

Keyword(s):

Pressure Sensor ◽

Biomedical Applications ◽

Circuit Simulation ◽

Applied Pressure ◽

Pressure Sensors ◽

Cmos Technology ◽

Current Mirror ◽

Sensing Element ◽

Pressure Sensing ◽

Cmos Mems

This paper reports on the design and optimization of current mirror MOSFET embedded pressure sensor. A current mirror circuit with an output current of 1 mA integrated with a pressure sensing n-channel MOSFET has been designed using standard 5 µm CMOS technology. The channel region of the pressure sensing MOSFET forms the flexible diaphragm as well as the strain sensing element. The piezoresistive effect in MOSFET has been exploited for the calculation of strain induced carrier mobility variation. The output transistor of the current mirror forms the active pressure sensing MOSFET which produces a change in its drain current as a result of altered channel mobility under externally applied pressure. COMSOL Multiphysics is utilized for the simulation of pressure sensing structure and Tspice is employed to evaluate the characteristics of the current mirror pressure sensing circuit. Simulation results show that the pressure sensor has a sensitivity of 10.01 mV/MPa. The sensing structure has been optimized through simulation for enhancing the sensor sensitivity to 276.65 mV/MPa. These CMOS-MEMS based pressure sensors integrated with signal processing circuitry on the same chip can be used for healthcare and biomedical applications.

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Three-Dimensional Arterial Pulse Signal Acquisition in Time Domain Using Flexible Pressure-Sensor Dense Arrays

Micromachines ◽

10.3390/mi12050569 ◽

2021 ◽

Vol 12 (5) ◽

pp. 569

Author(s):

Jianzhong Chen ◽

Ke Sun ◽

Rong Zheng ◽

Yi Sun ◽

Heng Yang ◽

...

Keyword(s):

Radial Artery ◽

Pressure Sensor ◽

Pulse Width ◽

Printed Circuit Boards ◽

Color Doppler ◽

Three Dimensional ◽

Pressure Sensors ◽

Sensor Arrays ◽

Signal Acquisition ◽

Dynamic Pulse

In this study, we developed a radial artery pulse acquisition system based on finger-worn dense pressure sensor arrays to enable three-dimensional pulse signals acquisition. The finger-worn dense pressure-sensor arrays were fabricated by packaging 18 ultra-small MEMS pressure sensors (0.4 mm × 0.4 mm × 0.2 mm each) with a pitch of 0.65 mm on flexible printed circuit boards. Pulse signals are measured and recorded simultaneously when traditional Chinese medicine practitioners wear the arrays on the fingers while palpating the radial pulse. Given that the pitches are much smaller than the diameter of the human radial artery, three-dimensional pulse envelope images can be measured with the system, as can the width and the dynamic width of the pulse signals. Furthermore, the array has an effective span of 11.6 mm—3–5 times the diameter of the radial artery—which enables easy and accurate positioning of the sensor array on the radial artery. This study also outlines proposed methods for measuring the pulse width and dynamic pulse width. The dynamic pulse widths of three volunteers were measured, and the dynamic pulse width measurements were consistent with those obtained by color Doppler ultrasound. The pulse wave velocity can also be measured with the system by measuring the pulse transit time between the pulse signals at the brachial and radial arteries using the finger-worn sensor arrays.

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SiOx microparticles embedded into 3D wrinkled N, S co-doped multilayer graphene sheets as a high-performance anode for long-life full lithium-ion batteries

Electrochimica Acta ◽

10.1016/j.electacta.2021.138841 ◽

2021 ◽

pp. 138841

Author(s):

Lu Shi ◽

Ying Li ◽

Yi Xing ◽

Riqiang Lin ◽

Guanggui Cheng ◽

...

Keyword(s):

Lithium Ion Batteries ◽

High Performance ◽

Lithium Ion ◽

Graphene Sheets ◽

Multilayer Graphene ◽

Long Life ◽

Co Doped

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Micromachined Pressure Sensors on Optical Fiber Tip

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.74.149 ◽

2009 ◽

Vol 74 ◽

pp. 149-152

Author(s):

X.M. Zhang ◽

M. Yu ◽

Silas Nesson ◽

H. Bae ◽

A. Christian ◽

...

Keyword(s):

Optical Fiber ◽

Pressure Sensor ◽

Linear Response ◽

Applied Pressure ◽

Pressure Sensors ◽

Outer Diameter ◽

Sensor Element ◽

Batch Fabrication ◽

In Vitro Measurements

This paper reports the development of a miniature pressure sensor on the optical fiber tip for in vitro measurements of rodent intradiscal pressure. The sensor element is biocompatible and can be fabricated by simple, batch-fabrication methods in a non-cleanroom environment with good device-to-device uniformity. The fabricated sensor element has an outer diameter of only 366 μm, which is small enough to be inserted into the rodent discs without disrupting the structure or altering the intradiscal pressures. In the calibration, the sensor element exhibits a linear response to the applied pressure over the range of 0 - 70 kPa, with a sensitivity of 0.0206 μm/kPa and a resolution of 0.17 kPa.

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Meso-origami: Folding multilayer graphene sheets

Applied Physics Letters ◽

10.1063/1.3223783 ◽

2009 ◽

Vol 95 (12) ◽

pp. 123121 ◽

Cited By ~ 144

Author(s):

Steven Cranford ◽

Dipanjan Sen ◽

Markus J. Buehler

Keyword(s):

Graphene Sheets ◽

Multilayer Graphene

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Design and Simulation of Pressure Sensor for Ocean Depth Measurements

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.313-314.666 ◽

2013 ◽

Vol 313-314 ◽

pp. 666-670 ◽

Cited By ~ 5

Author(s):

K.J. Suja ◽

Bhanu Pratap Chaudhary ◽

Rama Komaragiri

Keyword(s):

Pressure Sensor ◽

Integrated Circuit ◽

Output Voltage ◽

Pressure Sensors ◽

Micro Electro Mechanical System ◽

Constant Thickness ◽

Piezoresistive Pressure Sensor ◽

Wide Pressure Range ◽

Processing Techniques ◽

Wide Pressure

MEMS (Micro Electro Mechanical System) are usually defined as highly miniaturized devices combining both electrical and mechanical components that are fabricated using integrated circuit batch processing techniques. Pressure sensors are usually manufactured using square or circular diaphragms of constant thickness in the order of few microns. In this work, a comparison between circular diaphragm and square diaphragm indicates that square diaphragm has better perspectives. A new method for designing diaphragm of the Piezoresistive pressure sensor for linearity over a wide pressure range (approximately double) is designed, simulated and compared with existing single diaphragm design with respect to diaphragm deflection and sensor output voltage.

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