scholarly journals Hydrogen-Terminated Diamond Surface as a Gas Sensor: A Comparative Study of Its Sensitivities

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5390
Author(s):  
Michal Kočí ◽  
Alexander Kromka ◽  
Adam Bouřa ◽  
Ondrej Szabó ◽  
Miroslav Husák
Keyword(s):  
Gas Sensor ◽  
Output Voltage ◽  
Gas Sensing ◽  
Layer Structure ◽  
Active Material ◽  
Diamond Surface ◽  
Resistance Change ◽  
Pyroelectric Sensor ◽  
Conductivity Sensor ◽  
Voltage Change

A nanocrystalline diamond (NCD) layer is used as an active (sensing) part of a conductivity gas sensor. The properties of the sensor with an NCD with H-termination (response and time characteristic of resistance change) are measured by the same equipment with a similar setup and compared with commercial sensors, a conductivity sensor with a metal oxide (MOX) active material (resistance change), and an infrared pyroelectric sensor (output voltage change) in this study. The deposited layer structure is characterized and analyzed by Scanning Electron Microscopy (SEM) and Raman spectroscopy. Electrical properties (resistance change for conductivity sensors and output voltage change for the IR pyroelectric sensor) are examined for two types of gases, oxidizing (NO2) and reducing (NH3). The parameters of the tested sensors are compared and critically evaluated. Subsequently, differences in the gas sensing principles of these conductivity sensors, namely H-terminated NCD and SnO2, are described.

scholarly journals Gas Sensing Characteristics of a WO3 Thin Film Prepared by a Sol-Gel Method

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 723 ◽  
Author(s):  
Mitsuaki Yano ◽  
Tomoya Iwata ◽  
Satoshi Murakami ◽  
Ryouma Kamei ◽  
Taichi Inoue ◽  
...  
Keyword(s):  
Thin Film ◽  
Gas Sensor ◽  
Gas Sensing ◽  
Sol Gel ◽  
Poly Vinyl Alcohol ◽  
Resistance Change ◽  
Gel Method ◽  
Gas Concentration ◽  
Sol Gel Method ◽  
Aqueous Mixture

Preparation and characterization of a WO3-based thin film gas sensor are reported. The WO3 film was prepared on a polished alumina substrate by a sol-gel method using an aqueous mixture solution of ammonium metatungstate hydrate and poly-vinyl alcohol, and fabricated into the gas sensor by forming interdigital electrodes on the surface. The characterization was conducted by measuring the electrical resistance change in NO, H2, and NH3 ambient as a function of gas concentration. It is revealed that the sensor has a specific sensitivity to NO, NO is detected as oxidizing gas although it is expected to be reducing gas, and the resistance changes with gas concentration in accordance with the Langmuir isotherm plot.

scholarly journals Design and Fabrication of MOS Type Gas Sensor with Vertically Integrated Heater Using CMOS-MEMS Technology

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 772 ◽  
Author(s):  
Ya-Chu Lee ◽  
Ping-Lin Yang ◽  
Chun-I Chang ◽  
Weileun Fang
Keyword(s):  
Metal Oxide ◽  
Gas Sensor ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Low Cost ◽  
Oxide Semiconductor ◽  
Cmos Process ◽  
Resistance Change ◽  
Mems Technology ◽  
Cmos Mems

This study implements the metal-oxide-semiconductor (MOS) type gas sensor using the TSMC 0.35 μm 2P4M process. The gas concentration is detected based on the resistance change measured by the proposed sensor. This design has three merits: (1) low-cost post-CMOS process using metal/oxide wet etching, (2) composite sensing material based on ZnO-SnO2 coating on the CMOS-MEMS structure, (3) vertical integration of heater and ZnO-SnO2 gas-sensing films using CMOS-MEMS and drop casting technologies. Proposed design significantly increase the sensitivity at the high operating temperature. In summary, the sensitivity of presented sensor increased from 0.04%/% (O2/N2) at near room operating temperature to 0.2%/%(O2/N2) at near 140 °C for the range of 5–50% oxygen concentration.

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 Molecular bridge-mediated ultralow-power gas sensing

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Aishwaryadev Banerjee ◽  
Shakir-Ul Haque Khan ◽  
Samuel Broadbent ◽  
Ashrafuzzaman Bulbul ◽  
Kyeong Heon Kim ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Electron Tunneling ◽  
Gold Surface ◽  
Gold Electrodes ◽  
Self Assembled Monolayer ◽  
Output Resistance ◽  
Resistance Change ◽  
Ultralow Power ◽  
Linker Molecules ◽  
Molecular Bridge

AbstractWe report the electrical detection of captured gases through measurement of the quantum tunneling characteristics of gas-mediated molecular junctions formed across nanogaps. The gas-sensing nanogap device consists of a pair of vertically stacked gold electrodes separated by an insulating 6 nm spacer (~1.5 nm of sputtered α-Si and ~4.5 nm ALD SiO2), which is notched ~10 nm into the stack between the gold electrodes. The exposed gold surface is functionalized with a self-assembled monolayer (SAM) of conjugated thiol linker molecules. When the device is exposed to a target gas (1,5-diaminopentane), the SAM layer electrostatically captures the target gas molecules, forming a molecular bridge across the nanogap. The gas capture lowers the barrier potential for electron tunneling across the notched edge region, from ~5 eV to ~0.9 eV and establishes additional conducting paths for charge transport between the gold electrodes, leading to a substantial decrease in junction resistance. We demonstrated an output resistance change of >108 times upon exposure to 80 ppm diamine target gas as well as ultralow standby power consumption of <15 pW, confirming electron tunneling through molecular bridges for ultralow-power gas sensing.

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 iHEART: a miniaturized near-infrared in-line gas sensor using heart-shaped substrate-integrated hollow waveguides

The Analyst ◽  
2016 ◽  
Vol 141 (18) ◽  
pp. 5298-5303 ◽  
Author(s):  
Rafael L. Ribessi ◽  
Thiago de A. Neves ◽  
Jarbas J. R. Rohwedder ◽  
Celio Pasquini ◽  
Ivo M. Raimundo ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Near Infrared ◽  
Gas Sensing ◽  
Hollow Waveguide ◽  
Hollow Waveguides ◽  
Sensing System

Integration of a heart-shaped substrate-integrated hollow waveguide with a micro-spectrometer results in an ultra-compact gas sensing system: iHEART.

Perovskite-structured LaCoO3 modified ZnO gas sensor and investigation on its gas sensing mechanism by first principle

2021 ◽  
Vol 341 ◽  
pp. 130015
Author(s):  
Wenbo Qin ◽  
Zhenyu Yuan ◽  
Hongliang Gao ◽  
Renze Zhang ◽  
Fanli Meng
Keyword(s):  
Gas Sensor ◽  
Gas Sensing ◽  
First Principle ◽  
Sensing Mechanism
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