Optimization of MEMS Design for a Synchronous Magnetic Sensor

2007 ◽  
Author(s):  
S. Chandrasekaran ◽  
E. Berkcan
Keyword(s):  
Thin Film ◽  
Pathogen Detection ◽  
Microelectromechanical Systems ◽  
Gas Sensing ◽  
Low Cost ◽  
High Sensitivity ◽  
Vibration Monitoring ◽  
Flow Sensing ◽  
Biological Warfare Agents ◽  
Warfare Agents

Microelectromechanical systems offer variety of advantages such as small size, higher sensitivity, low cost because of mass fabrication capabilities and ease of implementation. Thin film cantilever based devices have been successfully used for variety of applications not limited to chemical vapors for chemical agents, biological warfare agents, contaminants in water, explosives, acoustics, vibration monitoring, flow sensing, viscosity and density measurements, antibody, pathogen detection, acceleration, shock sensing and magnetic field sensing. Thin film cantilevers can easily realized on silicon and other surfaces. Microcantilevers supported on one edge of the substrate can be designed to demonstrate very high sensitivity to very less force of the order of piconewtons. These structures could be extended for application in gas sensing if chemically sensitive layer is added on to the cantilever. The dimensions of the cantilever determine the sensitivity. Cantilevers as thin as few tenths of nanometer in thickness has been successfully demonstrated. Challenge associated with these devices when used as a sensor is their response to shock and acceleration.

scholarly journals Surface plasmon assisted toxic chemical NO<sub>2</sub> gas sensor by Au ∕ ZnO functional thin films

2021 ◽  
Vol 10 (2) ◽  
pp. 163-169
Author(s):  
Ravinder Gaur ◽  
Himanshu Mohan Padhy ◽  
Manikandan Elayaperumal
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Optical Properties ◽  
Surface Plasmon ◽  
Gas Sensing ◽  
Low Cost ◽  
High Sensitivity ◽  
Film Material ◽  
Hybrid Thin Film ◽  
Spr Sensor

Abstract. In this short communication, we propose a surface plasmon resonance (SPR) sensor based on a ZnO / Au hybrid thin-film material structure and experimentally investigate its sensitivity improvement. The Kretschmann-based SPR sensor utilizes ZnO thin films and nanostructures for performance enhancement. The advancement in SPR technology relies on a low-cost, high-sensitivity, and high-selectivity sensor. Metal oxide (MO) has been incorporated into the SPR sensor to be used for detection of biological and chemical compounds. ZnO as one of the metal oxides is an attractive material due to its unique physical and optical properties. Numerous techniques for fabrication and characterization of ZnO on SPR gold substrate have been studied. The mechanism for gas and biomolecule detection depends on their interaction with the ZnO surface, which is mainly attributed to the high isoelectric point of ZnO. There are several types of ZnO nanostructures which have been employed for SPR application based on the Kretschmann configuration. In the future, the thin film and nanostructures of ZnO could be a potential application for miniature design, robust, high sensitivity, and a low-cost portable type of SPR biosensor to be used for on-site testing in a real-time and label-free manner. The present work includes the application of a developed SPR setup for gas sensing at room temperature using a specially designed gas cell. The change in the optical properties of dielectric layers (ZnO) with adsorption of gases (NO2) in order to develop an optical sensor has been presented. The obtained results emphasize the applications of an SPR setup for the study of interaction of adsorbed gas molecules, with dielectrics and gas sensing.

scholarly journals Yttrium Doped TiO2 Thin Film for Gas Sensing Application Prepared by Spin Coating Method

2020 ◽  
Author(s):  
M Abdul Kaiyum ◽  
Naim Ahmed ◽  
Arif Alam ◽  
M Shamimur Rahman
Keyword(s):  
Thin Film ◽  
Photoelectron Spectroscopy ◽  
Gas Sensing ◽  
Low Cost ◽  
Pure Titanium ◽  
X Ray ◽  
Sensing Applications ◽  
Coating Method ◽  
Set Up ◽  
Spin Coater

Abstract Yttrium (Y) doped and pure Titanium Di-oxide (TiO2) thin films were prepared by using spin coater. The coater was set up in laboratory with low cost investment. The films were calcined at 450 °C for 1 hour. For characterization, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Atomic Force Microscopy (AFM) were carried out. LCR Bridge - GW Instek LCR-821 was used for gas sensing applications. XPS showed that the change of electronic structure due to Y doping. SEM and AFM analysis were carried out to determine the surface morphology of the films. Yttrium (Y) decreased the crystallite size of the films and increased the surface roughness and porosity value, which was very good for many sensing applications. Gas sensing property of the deposited films were improved by the incorporation of yttrium impurities and the sensing property improved almost two times than pure TiO2 thin film. Different researches have been done their research related to this topic but no one researchers provide a precise explanation of their results, authors of this research have tried to do that. Moreover the films were prepared by a simple spin coater to reduce the production cost also.

Conductimetric Detection of Protein and Cancer Cells with Oxide Nanosensors

2007 ◽  
Vol 1010 ◽  
Author(s):  
Janagama Goud ◽  
P. Markondeya Raj ◽  
Jin Liu ◽  
Mahadevan Iyer ◽  
Z. L. Wang ◽  
...  
Keyword(s):  
Thin Film ◽  
Cancer Cells ◽  
Gas Sensing ◽  
Low Cost ◽  
Electrochemical Techniques ◽  
Oxide Thin Film ◽  
Thin Film Sensors ◽  
Biochemical Sensing ◽  
Rabbit Igg ◽  
Thin Film Oxides

AbstractSemiconducting oxides are widely known and commercially applied for their gas sensing properties. However, biochemical sensing has mostly depended on optical and electrochemical techniques that are more cumbersome. This work investigates the biosensing characteristics of ZnO nanobelts and ZnO thin films. Zinc oxide thin film sensors showed changes in conductivity after protein functionalization with rabbit IgG and hybridization with anti-rabbit IgG. Conductivity changes were also measured after coating the oxides with MCF-7 cancer cells and its antibodies. In another set of experiments, ZnO nanobelts showed systematic conductivity changes with rabbit IgG protein hybridization. The experimental results in this paper indicate that the conductimetric properties of nano and thin film oxides can be sensitized to protein and cancer cell hybridization reactions. This technique can also be applied to certain other pathogen proteins or toxic proteins from the environment leading to low-cost miniaturized wireless biosensors.

Gas Sensing Properties of TiO2 and SnO2 Nanopowders Obtained through Gel Combustion

2006 ◽  
Vol 45 ◽  
pp. 1828-1833
Author(s):  
Fabio A. Deorsola ◽  
P. Mossino ◽  
Ignazio Amato ◽  
Bruno DeBenedetti ◽  
A. Bonavita ◽  
...  
Keyword(s):  
Response Time ◽  
Metal Oxides ◽  
Gas Sensing ◽  
Low Cost ◽  
High Sensitivity ◽  
Fast Response ◽  
High Specific Surface Area ◽  
Research Field ◽  
Wide Range ◽  
Gel Combustion

Nanostructured semiconductor metal oxides have played a central role in the gas sensing research field, because of their high sensitivity, selectivity and low response time. Among all the processes, developed for the synthesis of nanostructured metal oxides, gel combustion seems to be the most promising route due to low-cost precursors and simplicity of the process. It combines chemical gelation and combustion, involving the formation of a gel from an acqueous solution and an exothermic redox reaction, yielding to very porous and softly agglomerated nanopowders. In this work, nanostructured tin oxide, SnO2, and titanium oxide, TiO2, have been synthesized through gel combustion. Powders showed nanometric particle size and high specific surface area. The so-obtained TiO2 and SnO2 nanopowders have been used as sensitive element of resistive λ sensor and ethanol sensor respectively, realized depositing films of nanopowders dispersed in water onto alumina substrates provided with Pt contacts and heater. TiO2-based sensors showed at high temperature good response, fast response time, linearity in a wide range of O2 concentration and long-term stability. SnO2-based sensors have shown high sensitivity to low concentrations of ethanol at moderate temperature.

A multipurpose biochip for food pathogen detection

2016 ◽  
Vol 8 (15) ◽  
pp. 3055-3060 ◽  
Author(s):  
Elisabetta Primiceri ◽  
Maria Serena Chiriacò ◽  
Francesco de Feo ◽  
Elisa Santovito ◽  
Vincenzina Fusco ◽  
...  
Keyword(s):  
Pathogen Detection ◽  
Low Cost ◽  
High Sensitivity ◽  
Label Free ◽  
Food Pathogen

We realized an innovative biosensing platform with high sensitivity, low-cost and label-free features forS. aureusandL. monocytogenesdetection from meat.

scholarly journals Embedded Transdermal Alcohol Detection via a Finger Using SnO2 Gas Sensors

Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6852
Author(s):  
Fatima Ezahra Annanouch ◽  
Virginie Martini ◽  
Tomas Fiorido ◽  
Bruno Lawson ◽  
Khalifa Aguir ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Tin Dioxide ◽  
Gas Sensing ◽  
Low Cost ◽  
High Sensitivity ◽  
Rf Magnetron Sputtering ◽  
Alcohol Concentration ◽  
Invasive Technique ◽  
Clear Correlation ◽  
Wide Range

In this paper, we report the fabrication and characterization of a portable transdermal alcohol sensing device via a human finger, using tin dioxide (SnO2) chemoresistive gas sensors. Compared to conventional detectors, this non-invasive technique allowed us the continuous monitoring of alcohol with low cost and simple fabrication process. The sensing layers used in this work were fabricated by using the reactive radio frequency (RF) magnetron sputtering technique. Their structure and morphology were investigated by means of X-ray spectroscopy (XRD) and scanning electron microscopy (SEM), respectively. The results indicated that the annealing time has an important impact on the sensor sensitivity. Before performing the transdermal measurements, the sensors were exposed to a wide range of ethanol concentrations and the results displayed good responses with high sensitivity, stability, and a rapid detection time. Moreover, against high relative humidity (50% and 70%), the sensors remained resistant by showing a slight change in their gas sensing performances. A volunteer (an adult researcher from our volunteer group) drank 50 mL of tequila in order to realize the transdermal alcohol monitoring. Fifteen minutes later, the volunteer’s skin started to evacuate alcohol and the sensor resistance began to decline. Simultaneously, breath alcohol measurements were attained using a DRAGER 6820 certified breathalyzer. The results demonstrated a clear correlation between the alcohol concentration in the blood, breath, and via perspiration, which validated the embedded transdermal alcohol device reported in this work.

scholarly journals Regenerable Bead-Based Microfluidic Device with integrated THIN-Film Photodiodes for Real Time Monitoring of DNA Detection

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 953
Author(s):  
Catarina R. F. Caneira ◽  
Denis R. Santos ◽  
Virginia Chu ◽  
João P. Conde
Keyword(s):  
Thin Film ◽  
Real Time ◽  
Microfluidic Device ◽  
Low Cost ◽  
High Sensitivity ◽  
Significant Loss ◽  
Real Time Monitoring ◽  
Target Dna ◽  
On Chip ◽  
Biosensing System

Nanoporous microbead-based microfluidic systems for biosensing applications allow enhanced sensitivities, while being low cost and amenable for miniaturization. The regeneration of the microfluidic biosensing system results in a further decrease in costs while the integration of on-chip signal transduction enhances portability. Here, we present a regenerable bead-based microfluidic device, with integrated thin-film photodiodes, for real-time monitoring of molecular recognition between a target DNA and complementary DNA (cDNA). High-sensitivity assay cycles could be performed without significant loss of probe DNA density and activity, demonstrating the potential for reusability, portability and reproducibility of the system.

scholarly journals Fast infectious diseases diagnostics based on microfluidic biochip system

2017 ◽  
Vol 10 (02) ◽  
pp. 1650044 ◽  
Author(s):  
Qin Huang ◽  
Shanqiao Han ◽  
Yan Zhang ◽  
Yue Kou ◽  
Xiaohang Zhao ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Molecular Diagnostics ◽  
Microfluidic Chip ◽  
Pathogen Detection ◽  
Low Cost ◽  
High Sensitivity ◽  
Optical Diffraction ◽  
Fluorescence Detector ◽  
Total Analysis System ◽  
Amplification Method

Molecular diagnostics is one of the most important tools currently in use for clinical pathogen detection due to its high sensitivity, specificity, and low consume of sample and reagent is keyword to low cost molecular diagnostics. In this paper, a sensitive DNA isothermal amplification method for fast clinical infectious diseases diagnostics at aM concentrations of DNA was developed using a polycarbonate (PC) microfluidic chip. A portable confocal optical fluorescence detector was specifically developed for the microfluidic chip that was capable of highly sensitive real-time detection of amplified products for sequence-specific molecular identification near the optical diffraction limit with low background. The molecular diagnostics of Listeria monocytogenes with nucleic acid extracted from stool samples was performed at a minimum DNA template concentration of 3.65[Formula: see text]aM, and a detection limit of less than five copies of genomic DNA. Contrast to the general polymerase chain reaction (PCR) at eppendorf (EP) tube, the detection time in our developed method was reduced from 1.5[Formula: see text]h to 45[Formula: see text]min for multi-target parallel detection, the consume of sample and reagent was dropped from 25[Formula: see text][Formula: see text]L to 1.45[Formula: see text][Formula: see text]L. This novel microfluidic chip system and method can be used to develop a micro total analysis system as a clinically relevant pathogen molecular diagnostics method via the amplification of targets, with potential applications in biotechnology, medicine, and clinical molecular diagnostics.

scholarly journals Visible Light-Assisted Photoreduction of Graphene Oxide Using CdS Nanoparticles and Gas Sensing Properties

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Amirhossein Hasani ◽  
Hamed Sharifi Dehsari ◽  
Ali Amiri Zarandi ◽  
Alireza Salehi ◽  
Faramarz Afshar Taromi ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Gas Sensing ◽  
Irradiation Time ◽  
Low Cost ◽  
Direct Interaction ◽  
Reduction Process ◽  
High Sensitivity ◽  
Cds Nanoparticles ◽  
Gas Sensing Properties ◽  
Graphene Oxide Sheets

Graphene oxide sheets suspended in ethanol interact with excited CdS nanoparticles and contributed to photocatalytic reduction by accepting electron from nanoparticle. The UV-Vis measurement showed that electrical absorbance of the CdS/graphene oxide sheets increased by decreasing the irradiation time and after 2 h it remained constant which indicates the optimum reduction time. Furthermore, the direct interaction between CdS nanoparticles and graphene sheets hinders the collapse of exfoliated sheets of graphene. The 4-point probe measurement of nanocomposite with different ratios of graphene oxide in CdS solution after irradiation shows that the conductivity of them increased by increasing the amount of GO, but further increasing causes incomplete photo reduction process due to exorbitance increasing GO sheets which contribute to decreasing the conductivity. The CdS/RGO composite material can be used as a gas sensor for CO2based on its electrocatalytic behavior. The low-cost and easy fabrication sensor shows rapid response and high sensitivity. By varying the amount of GO the optimum concentration which shows high sensitivity is found and its good performance compared with other is attributed to its higher conductivity due to complete reduction. Moreover, the effects of thermal annealing on the conductivity of CdS/RGO film and the performance of devices are researched.

Optical Ammonia Sensor Based on ZnO:Eu2+ Fluorescence Quenching Nanoparticles

2018 ◽  
Vol 73 (9) ◽  
pp. 781-784 ◽  
Author(s):  
Wanting Yang ◽  
Wenlin Feng ◽  
Xiaozhan Yang ◽  
Hongliang Chen ◽  
Ying He ◽  
...  
Keyword(s):  
Fluorescence Quenching ◽  
Gas Sensing ◽  
Low Cost ◽  
Intensity Variation ◽  
High Sensitivity ◽  
Ammonia Sensor ◽  
Excitation Spectra ◽  
Ammonia Gas ◽  
Near Ultraviolet ◽  
Optical Gas Sensor

AbstractAn ammonia sensor is conceived and constructed using the downconverting ZnO:Eu2+ nanoparticles that can be excited by near-ultraviolet (378 nm) light and emit indigo color light. The capability of the ZnO:Eu2+ nanoparticles for ammonia gas sensing was studied from fluorescence quenching measurements. When these nanoparticles were exposed to ammonia gas, a significant luminescent intensity variation of the excitation spectra was observed. The detection limit of the proposed optical gas sensor is 20 ppm with a good linearity (R2 =0.9759) from 0 to 80 ppm of ammonia. The sensor has the advantages of a simple structure, high sensitivity, easy fabrication, and low cost, and can be used for sensing ammonia gas in factories, laboratories, etc.

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