Semiconductor Oxide Gas Sensors: Correlation between Conduction Mechanisms and Their Sensing Performances

2021 ◽  
Vol 5 (1) ◽  
pp. 71
Author(s):  
Ambra Fioravanti ◽  
Sara Morandi ◽  
Maria Cristina Carotta
Keyword(s):  
Gas Sensors ◽  
Screen Printing ◽  
Diffuse Reflectance ◽  
Gas Sensing ◽  
Electrical Characterization ◽  
Spectroscopic Techniques ◽  
Semiconducting Oxides ◽  
Ft Ir ◽  
Screen Printing Technology ◽  
Shed Light

In this work, a variety of semiconducting oxides were prepared and principally characterized by means of spectroscopic techniques (absorbance FT-IR, diffuse reflectance UV-Vis-NIR) to shed light on the electronic properties and defects involved at the roots of gas sensing capabilities. The thick films were obtained by screen printing technology on which electrical characterization and gas sensing measurements were performed. From the cross analysis of the results, a description of the specific sensing mechanism for each material is proposed.

Nano-Sized Semiconducting Oxide Powders for Thick Film Gas Sensors: From Powder Processing to Environmental Monitoring Devices

1999 ◽  
Vol 581 ◽  
Author(s):  
Enrico Traversa ◽  
Maria Cristina Carotta ◽  
Giuliano Martinelli
Keyword(s):  
Thick Film ◽  
Gas Sensors ◽  
Screen Printing ◽  
Powder Processing ◽  
International Standards ◽  
Electrical Measurements ◽  
Printing Technology ◽  
Semiconducting Oxides ◽  
Screen Printing Technology ◽  
Monitoring Devices

ABSTRACTThis paper reports the study of semiconducting oxides to develop gas sensors in thick-film form for use in atmospheric pollutant monitoring devices. The investigation was achieved with the following steps: selection of the suitable oxides and of their most appropriate processing method to obtain nano-sized powders, fabrication using screen-printing technology of thick-film sensors from these powders, and electrical measurements in laboratory and in the field. Chemical routes such as sol-gel techniques and thermal decomposition of heteronuclear complexes have been used to prepare nano-sized powders of n-type (TiO2) and p-type (LaFeO3 and SmFeO3) semiconducting oxides. Thick-film gas sensors have been produced by screen-printing technology. Pastes have been prepared and printed on laser precut 96% alumina substrates, each 2×2 mm element being provided with a heater, comb-type Au contacts and a Pt-100 resistor for controlling the operating temperature. The firing of the films has been performed in conditions able to keep grain size at nanometer level. Electrical responses to some major polluting gases (CO, NO, NO2 and O3) have been tested in laboratory and in the field, and compared with results of the analytical techniques approved by the international standards.

scholarly journals Enhancing Formaldehyde Selectivity of SnO2 Gas Sensors with the ZSM-5 Modified Layers

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 3947
Author(s):  
Wei Wang ◽  
Qinyi Zhang ◽  
Ruonan Lv ◽  
Dong Wu ◽  
Shunping Zhang
Keyword(s):  
Gas Sensors ◽  
Indoor Air ◽  
High Performance ◽  
Screen Printing ◽  
Gas Sensing ◽  
Oxide Semiconductors ◽  
Screen Printing Method ◽  
Gas Sensing Properties ◽  
Zeolite Films ◽  
Insufficient Knowledge

High performance formaldehyde gas sensors are widely needed for indoor air quality monitoring. A modified layer of zeolite on the surface of metal oxide semiconductors results in selectivity improvement to formaldehyde as gas sensors. However, there is insufficient knowledge on how the thickness of the zeolite layer affects the gas sensing properties. In this paper, ZSM-5 zeolite films were coated on the surface of the SnO2 gas sensors by the screen printing method. The thickness of ZSM-5 zeolite films was controlled by adjusting the numbers of screen printing layers. The influence of ZSM-5 film thickness on the performance of ZSM-5/SnO2 gas sensors was studied. The results showed that the ZSM-5/SnO2 gas sensors with a thickness of 19.5 μm greatly improved the selectivity to formaldehyde, and reduced the response to ethanol, acetone and benzene at 350 °C. The mechanism of the selectivity improvement to formaldehyde of the sensors was discussed.

scholarly journals Trends and Advances in the Characterization of Gas Sensing Materials Based on Semiconducting Oxides

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3544 ◽  
Author(s):  
David Degler
Keyword(s):  
Metal Oxides ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Academic Research ◽  
Spectroscopic Techniques ◽  
Characterization Methods ◽  
Fundamental Properties ◽  
Electronic Imaging ◽  
Semiconducting Metal Oxides

The understanding of the fundamental properties and processes of chemoresistive gas sensors based on semiconducting metal oxides is driven by the available characterization techniques and sophisticated approaches used to identify structure-function-relationships. This article summarizes trends and advances in the characterization of gas sensing materials based on semiconducting metal oxides, giving a unique overview of the state of the art methodology used in this field. The focus is set on spectroscopic techniques, but the presented concepts apply to other characterization methods, such as electronic, imaging or diffraction-based techniques. The presented concepts are relevant for academic research as well as for improving R&D approaches in industry.

scholarly journals Widely-Tunable Quantum Cascade-Based Sources for the Development of Optical Gas Sensors

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6650
Author(s):  
Virginie Zéninari ◽  
Raphaël Vallon ◽  
Laurent Bizet ◽  
Clément Jacquemin ◽  
Guillaume Aoust ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Tuning Range ◽  
Gas Sensing ◽  
Quantum Cascade Lasers ◽  
External Cavity ◽  
Infrared Region ◽  
Laser Resonator ◽  
Spectroscopic Techniques ◽  
Complex Species ◽  
Quantum Cascade

Spectroscopic techniques based on Distributed FeedBack (DFB) Quantum Cascade Lasers (QCL) provide good results for gas detection in the mid-infrared region in terms of sensibility and selectivity. The main limitation is the QCL relatively low tuning range (~10 cm−1) that prevents from monitoring complex species with broad absorption spectra in the infrared region or performing multi-gas sensing. To obtain a wider tuning range, the first solution presented in this paper consists of the use of a DFB QCL array. Tuning ranges from 1335 to 1387 cm−1 and from 2190 to 2220 cm−1 have been demonstrated. A more common technique that will be presented in a second part is to implement a Fabry–Perot QCL chip in an external-cavity (EC) system so that the laser could be tuned on its whole gain curve. The use of an EC system also allows to perform Intra-Cavity Laser Absorption Spectroscopy, where the gas sample is placed within the laser resonator. Moreover, a technique only using the QCL compliance voltage technique can be used to retrieve the spectrum of the gas inside the cavity, thus no detector outside the cavity is needed. Finally, a specific scheme using an EC coherent QCL array can be developed. All these widely-tunable Quantum Cascade-based sources can be used to demonstrate the development of optical gas sensors.

Synthesis and gas sensing properties of La and V Co-doped TiO2 thick film

2018 ◽  
Vol 11 (01) ◽  
pp. 1850019 ◽  
Author(s):  
Yongqi Wang ◽  
Yawen Dai
Keyword(s):  
Thin Film ◽  
Thick Film ◽  
Screen Printing ◽  
Gas Sensing ◽  
Sol Gel ◽  
Gas Sensing Properties ◽  
New Material ◽  
Screen Printing Technology ◽  
Different Gases ◽  
Co Doped

In this paper, we fabricated a new material based on the lanthanum (La) and vanadium (V) co-doped TiO2 by the sol–gel method, then used La and V codopant TiO2 power materials to fabricate the thin film type gas sensor by the screen-printing technology. Finally, we tested gas sensing response properties for different gases. We found La and V co-doped TiO2 simultaneously possess the La and V doping double characterization. In particular, the La and V co-doped samples showed a good response to formaldehyde, only slightly influenced by presence of benzene.

scholarly journals Editorial for the Special Issue on Nanostructure Based Sensors for Gas Sensing: from Devices to Systems

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 591
Author(s):  
Donato ◽  
Grassini
Keyword(s):  
Solid State ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Electrical Characterization ◽  
Analytical Techniques ◽  
Special Issue ◽  
Measurement Systems ◽  
Sensing Material

The development of solid state gas sensors based on microtransducers and nanostructured sensing materials is the key point in the design of new portable measurement systems with sensing and identification performances comparable with those of most sophisticated analytical techniques. In such a context, a lot of effort must be spent of course in the development of the sensing material, but also in the choice of the transducer mechanism and structure, in the electrical characterization of the sensor prototypes, as well as in the design of suitable measurement setups. [...]

Prospective of Conducting Polymer Nanowire for Gas Sensing Application to its Physical Scaling

2012 ◽  
Vol 584 ◽  
pp. 224-228 ◽  
Author(s):  
Dhammanand J. Shirale ◽  
Mangesh Bangar ◽  
Nosag V. Myung ◽  
Wilfred Chen ◽  
Girish M. Joshi ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Electrochemical Polymerization ◽  
Electrical Characterization ◽  
Alumina Template ◽  
Ammonia Gas ◽  
One Dimensional ◽  
Reliable Detection ◽  
Nanowire Device ◽  
Conducting Polypyrrole

The effect of physical scaling on one dimensional (1-D) conducting polypyrrole (Ppy) nanowire device has been successfully studied. The synthesis, electrical characterization and ammonia gas sensing with 1-D Ppy nanowire device have been carried out in the present investigation. Ppy nanowires having ~80 to ~200 nm in diameter were synthesized by electrochemical polymerization in alumina template and 1.77 to 3 µm Ppy nanowire length were maintain by varying the distance between electrodes gap. We further demonstrated that gas sensors based on 1-D Ppy nanowire having high aspect ratio (length to diameter ratio, L:D) exhibits good sensitivity towards ammonia, and provided a reliable detection at concentration as low as approximately 1 ppm based on principal of physical scaling co-related to response resistance.

scholarly journals Comparison of photoacoustic, diffuse reflectance, attenuated total reflectance and transmission infrared spectroscopy for the study of biochars

2018 ◽  
Vol 20 (4) ◽  
pp. 75-83 ◽  
Author(s):  
Sylwia Pasieczna-Patkowska ◽  
Jarosław Madej
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Diffuse Reflectance ◽  
Pyrolysis Temperature ◽  
Attenuated Total Reflectance ◽  
Signal Acquisition ◽  
Spectroscopic Techniques ◽  
Spectral Quality ◽  
Total Reflectance ◽  
Ft Ir

Abstract Four infrared spectroscopic techniques - photoacoustic (PAS), diffuse reflectance (DRS), attenuated total reflectance (ATR) and transmission (TS) - were evaluated for the qualitative analysis of the biochar obtained from willow feedstock during pyrolysis. Increase in pyrolysis temperature resulted in more aromatic and carbonaceous structure of biochars. These changes could easily be detected from Fourier transform infrared (FT-IR) spectral differences. The comparison of the spectra obtained by the four FT-IR techniques allowed to conclude that there are differences in the spectra acquired using different IR technique caused by different signal acquisition. PAS and ATR were the best techniques used in order to obtain spectra with smooth and sharp peaks, in contrast to TS, where bands were less-separated. DRS turned out to be the weakest of all techniques, due to poor spectral quality and poor separation of the bands.

Gas sensors based on semiconductor oxides: basic aspects onto materials and working principles

2004 ◽  
Vol 828 ◽  
Author(s):  
M. Cristina ◽  
Alessio Giberti ◽  
Vincenzo Guidi ◽  
Cesare Malagù ◽  
Beatrice Vendemiati ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Size Dependent ◽  
Barrier Heights ◽  
Oxide Powders ◽  
Semiconductor Oxides ◽  
Dependent Behavior ◽  
Wet Chemical ◽  
Nanocrystalline Oxides ◽  
Screen Printing Technology

ABSTRACTThe properties of the most important semiconductor oxides for gas sensing, such as SnO2, TiO2, WO3 and their modifications due to ion-addition or to catalyzers, have been reviewed. The oxide powders, synthesized via wet chemical routes, have been characterized both as dispersed powders and as sintered films. Deposition of thick film gas sensors was carried out through screen-printing technology. They have been studied comparing the electrical behavior under identical environmental conditions. Potential barrier heights have been measured via stimulated temperature measurements and density of ionized donors obtained via Hall Effect. A theoretical model has been developed to justify the size dependent behavior of nanocrystalline oxides.

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