scholarly journals Gas Adsorption Investigation on SiGe Monolayer: A First-Principle Calculation

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2879
Author(s):  
Xiang Sun ◽  
Yuzheng Guo ◽  
Yan Zhao ◽  
Sheng Liu ◽  
Hui Li
Keyword(s):  
Gas Adsorption ◽  
Gas Sensing ◽  
First Principles Calculation ◽  
First Principle Calculation ◽  
Adsorption Sites ◽  
Sensing Applications ◽  
Adsorption Behaviors ◽  
Sensing Material ◽  
Nh3 Adsorption ◽  
No2 Adsorption

The gas adsorption behaviors of CO, CO2, SO2, NO2, NO, NH3, H2, H2O, and O2 on SiGe monolayer are studied using the first-principles calculation method. Three special adsorption sites and different gas molecule orientations are considered. Based on adsorption energy, band gap, charge transfer, and the electron localization function, the appropriate physical adsorptions of SO2, NO, NH3, and O2 are confirmed. These gases possess excellent adsorption properties that demonstrate the obvious sensitiveness of SiGe monolayer to these gases. Moreover, SiGe may be used as a sensing material for some of them. NO2 adsorption in different adsorption sites can be identified as chemical adsorption. Besides, the external electric field can effectively modify the adsorption strength. The range of 0 ~ − 2 V/nm can create a desorption effect when NH3 adsorbs at the Ge site. The NH3 adsorption models on Ge site are chosen to investigate the properties of the I-V curve. Our theoretical results indicate that SiGe monolayer is a promising candidate for gas sensing applications.

scholarly journals Polymer-Templated Durable and Hydrophobic Nanostructures for Hydrogen Gas Sensing Applications

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4470
Author(s):  
Mohammad Kamal Hossain ◽  
Qasem Ahmed Drmosh
Keyword(s):  
Contact Angle ◽  
Surface Area ◽  
Gas Adsorption ◽  
Sessile Drop ◽  
Gas Sensing ◽  
Hydrogen Gas ◽  
Adsorption Sites ◽  
Wetting Contact Angle ◽  
Sensing Applications ◽  
Surface Nanostructures

A simple and hands-on one-step process has been implemented to fabricate polymer-templated hydrophobic nanostructures as hydrogen gas sensing platforms. Topographic measurements have confirmed irregular hills and dips of various dimensions that are responsible for creating air bubble pockets that satisfy the Cassie–Baxter state of hydrophobicity. High-resolution field-emission scanning electron microscopy (FESEM) has revealed double-layer structures consisting of fine microscopic flower-like structures of nanoscale petals on the top of base nanostructures. Wetting contact angle (WCA) measurements further revealed the contact angle to be ~142.0° ± 10.0°. Such hydrophobic nanostructures were expected to provide a platform for gas-sensing materials of a higher surface area. From this direction, a very thin layer of palladium, ca. 100 nm of thickness, was sputtered. Thereafter, further topographic and WCA measurements were carried out. FESEM micrographs revealed that microscopic flower-like structures of nanoscale petals remained intact. A sessile drop test reconfirmed a WCA of as high as ~130.0° ± 10.0°. Due to the inherent features of hydrophobic nanostructures, a wider surface area was expected that can be useful for higher target gas adsorption sites. In this context, a customized sensing facility was set up, and H2 gas sensing performance was carried out. The surface nanostructures were found to be very stable and durable over the course of a year and beyond. A polymer-based hydrophobic gas-sensing platform as investigated in this study will play a dual role in hydrophobicity as well as superior gas-sensing characteristics.

scholarly journals Graphene functionalised by laser-ablated V2O5 for a highly sensitive NH3 sensor

2017 ◽  
Vol 8 ◽  
pp. 571-578 ◽  
Author(s):  
Margus Kodu ◽  
Artjom Berholts ◽  
Tauno Kahro ◽  
Mati Kook ◽  
Peeter Ritslaid ◽  
...  
Keyword(s):  
Gas Adsorption ◽  
Gas Sensing ◽  
Metal Oxide Nanoparticles ◽  
Single Layer ◽  
High Energy ◽  
Single Layer Graphene ◽  
Adsorption Sites ◽  
Time Sensitivity ◽  
Sensing Material ◽  
Induced Defects

Graphene has been recognized as a promising gas sensing material. The response of graphene-based sensors can be radically improved by introducing defects in graphene using, for example, metal or metal oxide nanoparticles. We have functionalised CVD grown, single-layer graphene by applying pulsed laser deposition (PLD) of V2O5 which resulted in a thin V2O5 layer on graphene with average thickness of ≈0.6 nm. From Raman spectroscopy, it was concluded that the PLD process also induced defects in graphene. Compared to unmodified graphene, the obtained chemiresistive sensor showed considerable improvement of sensing ammonia at room temperature. In addition, the response time, sensitivity and reversibility were essentially enhanced due to graphene functionalisation by laser deposited V2O5. This can be explained by an increased surface density of gas adsorption sites introduced by high energy atoms in laser ablation plasma and formation of nanophase boundaries between deposited V2O5 and graphene.

scholarly journals Nitrogen-Containing Gas Sensing Properties of 2-D Ti2N and Its Derivative Nanosheets: Electronic Structures Insight

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2459
Author(s):  
Hongni Zhang ◽  
Wenzheng Du ◽  
Jianjun Zhang ◽  
Rajeev Ahuja and Zhao Qian
Keyword(s):  
Density Functional ◽  
Gas Adsorption ◽  
Gas Sensing ◽  
Density Functional Theory Calculations ◽  
Fast Response ◽  
Two Dimensional ◽  
Sensing Applications ◽  
Sensing Material ◽  
Physical Insight ◽  
The Stability

In this work, the potentials of two-dimensional Ti2N and its derivative nanosheets Ti2NT2(T=O, F, OH) for some harmful nitrogen-containing gas (NCG) adsorption and sensing applications have been unveiled based on the quantum-mechanical Density Functional Theory calculations. It is found that the interactions between pure Ti2N and NCGs (including NO, NO2, and NH3 in this study) are very strong, in which NO and NO2 can even be dissociated, and this would poison the substrate of Ti2N monolayer and affect the stability of the sensing material. For the monolayer of Ti2NT2(T=O, F, OH) that is terminated by functional groups on surface, the adsorption energies of NCGs are greatly reduced, and a large amount of charges are transferred to the functional group, which is beneficial to the reversibility of the sensing material. The significant changes in work function imply the good sensitivity of the above mentioned materials. In addition, the fast response time further consolidates the prospect of two-dimensional Ti2NT2 as efficient NCGs’ sensing materials. This theoretical study would supply physical insight into the NCGs’ sensing mechanism of Ti2N based nanosheets and help experimentalists to design better 2-D materials for gas adsorption or sensing applications.

scholarly journals Optimization of a Low-Power Chemoresistive Gas Sensor: Predictive Thermal Modelling and Mechanical Failure Analysis

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 783 ◽  
Author(s):  
Andrea Gaiardo ◽  
David Novel ◽  
Elia Scattolo ◽  
Michele Crivellari ◽  
Antonino Picciotto ◽  
...  
Keyword(s):  
Low Power ◽  
Failure Analysis ◽  
Gas Sensors ◽  
High Performance ◽  
Gas Sensing ◽  
Mechanical Failure ◽  
Sensing Applications ◽  
Theoretical Approaches ◽  
Sensing Material ◽  
Silicon Bulk

The substrate plays a key role in chemoresistive gas sensors. It acts as mechanical support for the sensing material, hosts the heating element and, also, aids the sensing material in signal transduction. In recent years, a significant improvement in the substrate production process has been achieved, thanks to the advances in micro- and nanofabrication for micro-electro-mechanical system (MEMS) technologies. In addition, the use of innovative materials and smaller low-power consumption silicon microheaters led to the development of high-performance gas sensors. Various heater layouts were investigated to optimize the temperature distribution on the membrane, and a suspended membrane configuration was exploited to avoid heat loss by conduction through the silicon bulk. However, there is a lack of comprehensive studies focused on predictive models for the optimization of the thermal and mechanical properties of a microheater. In this work, three microheater layouts in three membrane sizes were developed using the microfabrication process. The performance of these devices was evaluated to predict their thermal and mechanical behaviors by using both experimental and theoretical approaches. Finally, a statistical method was employed to cross-correlate the thermal predictive model and the mechanical failure analysis, aiming at microheater design optimization for gas-sensing applications.

scholarly journals On the design and characterisation of a microwave microstrip resonator for gas sensing applications

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 54
Author(s):  
Giovanni Gugliandolo ◽  
Davide Aloisio ◽  
Giuseppe Campobello ◽  
Giovanni Crupi ◽  
Nicola Donato
Keyword(s):  
Relative Humidity ◽  
Reflection Coefficient ◽  
Humidity Sensor ◽  
Gas Sensing ◽  
Microstrip Resonator ◽  
Resonant Frequencies ◽  
Sensing Applications ◽  
Sensing Material ◽  
Central Disk ◽  
Humidity Monitoring

This study focuses on the microwave characterisation of a microstrip resonator aimed for gas sensing applications. The developed one-port microstrip resonator, consisting of three concentric rings with a central disk, is coupled to a 50-Ohm microstrip feedline through a small gap. A humidity sensing layer is deposited on this gap by drop-coating an aqueous solution of Ag@alpha-Fe<sub>2</sub>O<sub>3</sub> nanocomposite. The operation principle of the developed humidity sensor is based on the change of the dielectric properties of the Ag@alpha-Fe<sub>2</sub>O<sub>3</sub> nanocomposite when the relative humidity is varied. However, it should be underlined that, depending on the choice of the sensing material, different target gases of interest can be detected with the proposed structure. The frequency-dependent response of the sensor is obtained using the reflection coefficient measured from 3.5 GHz to 5.6 GHz with relative humidity ranging from 0 %rh to 83 %rh. The variation of the humidity concentration strongly impacts on the two resonances detected in the measured reflection coefficient. In particular, an increase of the humidity level leads to lowering both resonant frequencies, which can be used as sensing parameters for humidity monitoring purpose. An exponential function has been used to accurately model the two resonant frequencies as a function of the humidity.

Fabrication of Metal@SnO2 Core-Shell Nanocomposites for Gas Sensing Applications

2015 ◽  
pp. 438-451
Author(s):  
Sanjay K. Suar ◽  
Sayantan Sinha ◽  
Amrita Mishra ◽  
Suraj K. Tripathy
Keyword(s):  
Thermal Stability ◽  
Gas Sensing ◽  
Chemical Species ◽  
Core Shell ◽  
Sensor Performance ◽  
Sensing Applications ◽  
Sensing Material ◽  
Response And Recovery ◽  
Interfacial Charge ◽  
Thermal Stability Of

Metal/SnO2 is one of the most popular composite systems because of its application in gas sensors, where the metal in contact with the SnO2 (semiconductor) enhances sensor performance in terms of sensitivity, response, and recovery time. This is because the metal acts as an electron reservoir, improving the depletion layer formation by interfacial charge-transfer process and delaying the electrons-holes recombination process in SnO2. Conventionally, the metal nanoparticles are anchored on the surface of SnO2 to produce hetero-interfaces. Despite effective catalytic activity, this structural drawback exposes metals to other chemical species. Therefore, it is necessary to design new strategies to improve the chemical and thermal stability of metal/SnO2. Recently, nanocomposites with metal core and SnO2 shell became potential candidates due to their chemical and thermal stability and superior material property. In this chapter, fabrication of metal@SnO2 core-shell nanocomposites are discussed as a potential gas sensing material.

Growth of Zinc Oxide Nanowires and Nanobelts for Gas Sensing Applications

2005 ◽  
Vol 23 ◽  
pp. 27-30 ◽  
Author(s):  
M.K. Hossain ◽  
S.C. Ghosh ◽  
Y. Boontongkong ◽  
Chanchana Thanachayanont ◽  
Joydeep Dutta
Keyword(s):  
Zinc Oxide ◽  
Electrical Resistance ◽  
Gas Sensing ◽  
Electrical Conductance ◽  
Analyte Molecule ◽  
Sensor Material ◽  
Surface And Interface ◽  
Sensing Applications ◽  
Sensing Material ◽  
Specific Material

Zinc Oxide (ZnO) is a very useful as a solid state gas sensor material. In chemical sensing the surface and interface interactions between the analyte molecules and the sensing material is all but important that is read through the changes in electrical conductance. In that sense, nano-objects with a large surface atom/bulk atom ratio, like nanoparticles and nanowires, are potentially the best chemical sensors. The mechanism envisioned involves the adsorption (and eventually diffusion) of the analyte molecule at the surface that induces a change in the electrical resistance of the nano-object. The most convenient way to measure changes in electrical resistance in such devices is to obtain the specific material as nanowires or as connected nanoparticles. Here, we will discuss about a low-temperature wet-chemical process of synthesizing ZnO nanoparticles, nanowires and nanobelts for application as gas sensors.

scholarly journals An Analytical Conductance Model for Gas Detection Based on a Zigzag Carbon Nanotube Sensor

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 357
Author(s):  
Ali Hosseingholipourasl ◽  
Sharifah Hafizah Syed Ariffin ◽  
Mohammad Taghi Ahmadi ◽  
Seyed Saeid Rahimian Koloor ◽  
Michal Petrů ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Band Structure ◽  
Gas Adsorption ◽  
Gas Sensing ◽  
Electrical Conductance ◽  
Analytical Models ◽  
Adsorption Effect ◽  
Sensing Applications ◽  
New Energy ◽  
Gas Molecules

Recent advances in nanotechnology have revealed the superiority of nanocarbon species such as carbon nanotubes over other conventional materials for gas sensing applications. In this work, analytical modeling of the semiconducting zigzag carbon nanotube field-effect transistor (ZCNT-FET) based sensor for the detection of gas molecules is demonstrated. We propose new analytical models to strongly simulate and investigate the physical and electrical behavior of the ZCNT sensor in the presence of various gas molecules (CO2, H2O, and CH4). Therefore, we start with the modeling of the energy band structure by acquiring the new energy dispersion relation for the ZCNT and introducing the gas adsorption effects to the band structure model. Then, the electrical conductance of the ZCNT is modeled and formulated while the gas adsorption effect is considered in the conductance model. The band structure analysis indicates that, the semiconducting ZCNT experiences band gap variation after the adsorption of the gases. Furthermore, the bandgap variation influences the conductance of the ZCNT and the results exhibit increments of the ZCNT conductance in the presence of target gases while the minimum conductance shifted upward around the neutrality point. Besides, the I-V characteristics of the sensor are extracted from the conductance model and its variations after adsorption of different gas molecules are monitored and investigated. To verify the accuracy of the proposed models, the conductance model is compared with previous experimental and modeling data and a good consensus is observed. It can be concluded that the proposed analytical models can successfully be applied to predict sensor behavior against different gas molecules.

Recent advances in 2D black phosphorus based materials for gas sensing applications

2021 ◽  
Vol 9 (11) ◽  
pp. 3773-3794
Author(s):  
Aaryashree ◽  
Pratik V. Shinde ◽  
Amitesh Kumar ◽  
Dattatray J. Late ◽  
Chandra Sekhar Rout
Keyword(s):  
Physicochemical Properties ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Black Phosphorus ◽  
Sensing Applications ◽  
Recent Advances ◽  
Sensing Material ◽  
Black Phosphorous

Black phosphorous (BP) has emerged as a potential sensing material due to its exceptional physicochemical properties. The review presents both the theoretical and experimental aspects of the BP-based gas sensors.

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