scholarly journals Analysis of Simulated Output Characteristics of Gas Sensor Based on Graphene Nanoribbon

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
A. Mahmoudi ◽  
M. Troudi ◽  
Y. Bergaoui ◽  
P. Bondavalli ◽  
N. Sghaier
Keyword(s):  
Gas Sensor ◽  
Gas Sensing ◽  
Channel Length ◽  
Graphene Nanoribbon ◽  
Sensor Model ◽  
Current Voltage ◽  
Output Characteristics ◽  
The Right ◽  
New Generation ◽  
The Given

This work presents simulated output characteristics of gas sensor transistors based on graphene nanoribbon (GNRFET). The device studied in this work is a new generation of gas sensing devices, which are easy to use, ultracompact, ultrasensitive, and highly selective. We will explain how the exposure to the gas changes the conductivity of graphene nanoribbon. The equations of the GNRFET gas sensor model include the Poisson equation in the weak nonlocality approximation with proposed sensing parameters. As we have developed this model as a platform for a gas detection sensor, we will analyze the current-voltage characteristics after exposure of the GNRFET nanosensor device to NH3gas. A sensitivity of nearly 2.7% was indicated in our sensor device after exposure of 1 ppm of NH3. The given results make GNRFET the right candidate for use in gas sensing/measuring appliances. Thus, we will investigate the effect of the channel length on the ON- and OFF-current.

scholarly journals An analytical approach to evaluate the performance of graphene and carbon nanotubes for NH3 gas sensor applications

2014 ◽  
Vol 5 ◽  
pp. 726-734 ◽  
Author(s):  
Elnaz Akbari ◽  
Vijay Kumar Arora ◽  
Aria Enzevaee ◽  
Mohamad T Ahmadi ◽  
Mehdi Saeidmanesh ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensor ◽  
Chemical Elements ◽  
Ambient Conditions ◽  
Detection Mechanism ◽  
Sensor Applications ◽  
Surface Molecules ◽  
Sensor Model ◽  
Current Voltage ◽  
Effect Transistor

Carbon, in its variety of allotropes, especially graphene and carbon nanotubes (CNTs), holds great potential for applications in variety of sensors because of dangling π-bonds that can react with chemical elements. In spite of their excellent features, carbon nanotubes (CNTs) and graphene have not been fully exploited in the development of the nanoelectronic industry mainly because of poor understanding of the band structure of these allotropes. A mathematical model is proposed with a clear purpose to acquire an analytical understanding of the field-effect-transistor (FET) based gas detection mechanism. The conductance change in the CNT/graphene channel resulting from the chemical reaction between the gas and channel surface molecules is emphasized. NH3 has been used as the prototype gas to be detected by the nanosensor and the corresponding current–voltage (I–V) characteristics of the FET-based sensor are studied. A graphene-based gas sensor model is also developed. The results from graphene and CNT models are compared with the experimental data. A satisfactory agreement, within the uncertainties of the experiments, is obtained. Graphene-based gas sensor exhibits higher conductivity compared to that of CNT-based counterpart for similar ambient conditions.

RF-MBE GROWTH OF GaN ON SAPPHIRE FOR GAS SENSING APPLICATION

2008 ◽  
Vol 17 (04) ◽  
pp. 435-442
Author(s):  
C. W. CHIN ◽  
Z. HASSAN ◽  
F. K. YAM
Keyword(s):  
Buffer Layer ◽  
Gas Sensor ◽  
Room Temperature ◽  
Gas Sensing ◽  
Annealed Sample ◽  
Rf Plasma ◽  
Mbe Growth ◽  
Group Iii ◽  
Current Voltage ◽  
Aln Buffer

Besides SiC , a group III-V nitrides are also suitable large-band gap semiconductor materials for high-temperature gas sensor devices. In this paper, we present the study of the H2 sensitive device fabricated based on n-type GaN wafer. The GaN thin film with AlN buffer layer was grown on sapphire by RF plasma-assisted molecular beam epitaxy (RF-MBE). A few monolayers of AlN were deposited using high flux Al before the growth of the AlN buffer layer. This step is speculated to be able to form a better relaxed layer for the subsequent growth of the AlN buffer layer. Pt contacts with thickness of about 150 nm were then deposited on the GaN/AlN/Al2O3 using the sputtering system. Gas detection was carried out at room temperature. Prior to the current–voltage (I–V) measurements, the samples were annealed at temperatures ranging from 200°C to 600°C in N2 ambience. A significant change of current in the Pt/ GaN gas sensor was observed for the 600°C annealed sample when exposed to 0.5% H2 in N2 gas.

The effect of concentration on gas sensor model based on graphene nanoribbon

2013 ◽  
Vol 24 (1) ◽  
pp. 143-146 ◽  
Author(s):  
Elnaz Akbari ◽  
Rubiyah Yousof ◽  
M. T. Ahmadi ◽  
M. J. Kiani ◽  
M. Rahmani ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Graphene Nanoribbon ◽  
Model Based ◽  
Sensor Model

Finding the Right Problems: Some HREM Applications to Interfaces

1984 ◽  
Vol 42 ◽  
pp. 376-379
Author(s):  
D. Cherns
Keyword(s):  
Grain Boundaries ◽  
High Resolution Electron Microscopy ◽  
Boundary Structure ◽  
Atomic Structures ◽  
Grain Boundary Structure ◽  
Resolution Electron ◽  
Point To Point ◽  
The Right ◽  
New Generation ◽  
Better Than

The use of high resolution electron microscopy (HREM) to determine the atomic structure of grain boundaries and interfaces is a topic of great current interest. Grain boundary structure has been considered for many years as central to an understanding of the mechanical and transport properties of materials. Some more recent attention has focussed on the atomic structures of metalsemiconductor interfaces which are believed to control electrical properties of contacts. The atomic structures of interfaces in semiconductor or metal multilayers is an area of growing interest for understanding the unusual electrical or mechanical properties which these new materials possess. However, although the point-to-point resolutions of currently available HREMs, ∼2-3Å, appear sufficient to solve many of these problems, few atomic models of grain boundaries and interfaces have been derived. Moreover, with a new generation of 300-400kV instruments promising resolutions in the 1.6-2.0 Å range, and resolutions better than 1.5Å expected from specialist instruments, it is an appropriate time to consider the usefulness of HREM for interface studies.

Metal-oxide based ammonia gas sensors: A review

2020 ◽  
Vol 10 ◽  
Author(s):  
Priya Gupta ◽  
Savita Maurya ◽  
Narendra Kumar Pandey ◽  
Vernica Verma
Keyword(s):  
Metal Oxide ◽  
Metal Oxides ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Review Paper ◽  
Gas Sensing ◽  
Gas Sensitivity ◽  
Ammonia Gas ◽  
Ammonia Sensing ◽  
Ammonia Gas Sensors

: This review paper encompasses a study of metal-oxide and their composite based gas sensors used for the detection of ammonia (NH3) gas. Metal-oxide has come into view as an encouraging choice in the gas sensor industry. This review paper focuses on the ammonia sensing principle of the metal oxides. It also includes various approaches adopted for increasing the gas sensitivity of metal-oxide sensors. Increasing the sensitivity of the ammonia gas sensor includes size effects and doping by metal or other metal oxides which will change the microstructure and morphology of the metal oxides. Different parameters that affect the performances like sensitivity, stability, and selectivity of gas sensors are discussed in this paper. Performances of the most operated metal oxides with strengths and limitations in ammonia gas sensing application are reviewed. The challenges for the development of high sensitive and selective ammonia gas sensor are also discussed.

scholarly journals Ammonia Gas Sensing Characteristic of P3HT-rGO-MWCNT Composite Films

2021 ◽  
Vol 11 (15) ◽  
pp. 6675
Author(s):  
Tran Si Trong Khanh ◽  
Tran Quang Trung ◽  
Le Thuy Thanh Giang ◽  
Tran Quang Nguyen ◽  
Nguyen Dinh Lam ◽  
...  
Keyword(s):  
Response Time ◽  
Gas Sensor ◽  
Gas Sensing ◽  
Composite Films ◽  
Weight Ratio ◽  
Film Surface ◽  
Relative Sensitivity ◽  
Ammonia Gas ◽  
Casting Technique ◽  
Multi Walled Carbon Nanotubes

In this work, the P3HT:rGO:MWCNTs (PGC) nanocomposite film applied to the ammonia gas sensor was successfully fabricated by a drop-casting technique. The results demonstrated that the optimum weight ratio of the PGC nanocomposite gas sensor is 20%:60%:20% as the weight ratio of P3HT:rGO:MWCNTs (called PGC-60). This weight ratio leads to the formation of nanostructured composites, causing the efficient adsorption/desorption of ammonia gas in/out of the film surface. The sensor based on PGC-60 possessed a response time of 30 s, sensitivity up to 3.6% at ammonia gas concentration of 10 ppm, and relative sensitivity of 0.031%/ppm. These results could be attributed to excellent electron transportation of rGO, the main adsorption activator to NH3 gas of P3HT, and holes move from P3HT to the cathodes, which works as charge “nano-bridges” carriers of Multi-Walled Carbon Nanotubes (MWCNTs). In general, these three components of PGC sensors have significantly contributed to the improvement of both the sensitivity and response time in the NH3 gas sensor.

scholarly journals Gold and ZnO-Based Metal-Semiconductor Network for Highly Sensitive Room-Temperature Gas Sensing

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3815
Author(s):  
Renyun Zhang ◽  
Magnus Hummelgård ◽  
Joel Ljunggren ◽  
Håkan Olin
Keyword(s):  
Solar Cells ◽  
Gas Sensor ◽  
Network Structure ◽  
Room Temperature ◽  
Gas Sensing ◽  
Zno Nanowires ◽  
Gold Particles ◽  
Highly Sensitive ◽  
Semiconductor Electronics ◽  
New Type

Metal-semiconductor junctions and interfaces have been studied for many years due to their importance in applications such as semiconductor electronics and solar cells. However, semiconductor-metal networks are less studied because there is a lack of effective methods to fabricate such structures. Here, we report a novel Au–ZnO-based metal-semiconductor (M-S)n network in which ZnO nanowires were grown horizontally on gold particles and extended to reach the neighboring particles, forming an (M-S)n network. The (M-S)n network was further used as a gas sensor for sensing ethanol and acetone gases. The results show that the (M-S)n network is sensitive to ethanol (28.1 ppm) and acetone (22.3 ppm) gases and has the capacity to recognize the two gases based on differences in the saturation time. This study provides a method for producing a new type of metal-semiconductor network structure and demonstrates its application in gas sensing.

scholarly journals Simple and rapid gas sensing using a single-walled carbon nanotube field-effect transistor-based logic inverter

2021 ◽  
Author(s):  
Salomé Forel ◽  
Leandro Sacco ◽  
Alice Castan ◽  
Ileana Florea ◽  
Costel Sorin Cojocaru
Keyword(s):  
Carbon Nanotube ◽  
Power Consumption ◽  
Data Processing ◽  
Gas Sensor ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Gas Sensing ◽  
Single Walled Carbon Nanotube ◽  
Effect Transistor ◽  
System Miniaturization

We design a gas sensor by combining two SWCNT-FET devices in an inverter configuration enabling a better system miniaturization together with a reduction of power consumption and ease of data processing.

scholarly journals Enhancing room-temperature NO2 gas sensing performance based on a metal phthalocyanine/graphene quantum dot hybrid material

RSC Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 5618-5628
Author(s):  
Wenkai Jiang ◽  
Xinwei Chen ◽  
Tao Wang ◽  
Bolong Li ◽  
Min Zeng ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Gas Sensor ◽  
Hybrid Material ◽  
High Performance ◽  
Room Temperature ◽  
Gas Sensing ◽  
Metal Phthalocyanine ◽  
Graphene Quantum Dot ◽  
Sensing Performance

A high performance gas sensor based on a metal phthalocyanine/graphene quantum dot hybrid material was fabricated for NO2 detection at room-temperature.

scholarly journals Improvement of Transverse-Flux Machine Characteristics by Finding an Optimal Air-Gap Diameter and Coil Cross-Section at the Given Magneto-Motive Force of the PMs

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 755
Author(s):  
Grebenikov Viktor ◽  
Oleksandr Dobzhanskyi ◽  
Gamaliia Rostislav ◽  
Rupert Gouws
Keyword(s):  
Cross Section ◽  
Computer Model ◽  
Single Phase ◽  
Air Gap ◽  
Laboratory Measurements ◽  
The Finite Element Method ◽  
Power Characteristics ◽  
Transverse Flux ◽  
Output Characteristics ◽  
The Given

This paper presents analysis and study of the single-phase transverse-flux machine. The finite element method results of the machine are compared with the laboratory measurements to confirm the accuracy of the computer model. This computer model is then used to investigate the effect of the machine’s geometry on its output characteristics. Parametric analysis of the machine is carried out to find the optimal air-gap diameter at which the cogging torque of the machine is minimal. In addition, the influence of the coil cross-section on the torque and output power characteristics of the machine is investigated and discussed.

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