scholarly journals Comparative NO2 Sensing Characteristics of SnO2:WO3 Thin Film Against Bulk and Investigation of Optical Properties of the Thin Film

2018 ◽  
Vol 15 (2) ◽  
pp. 227-233 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Gas Sensing ◽  
Comparative Investigation ◽  
X Ray Diffraction ◽  
Glass Substrates ◽  
Thin Film Sensors ◽  
Gas Sensing Properties ◽  
Evaporation Technique ◽  
Sensing Characteristics

A comparative investigation of gas sensing properties of SnO2 doped with WO3 based on thin film and bulk forms was achieved. Thin films were deposited by thermal evaporation technique on glass substrates. Bulk sensors in the shape of pellets were prepared by pressing SnO2:WO3 powder. The polycrystalline nature of the obtained films with tetragonal structure was confirmed by X-ray diffraction. The calculated crystalline size was 52.43 nm. Thickness of the prepared films was found 134 nm. The optical characteristics of the thin films were studied by using UV-VIS Spectrophotometer in the wavelength range 200 nm to 1100 nm, the energy band gap, extinction coefficient and refractive index of the thin film were 2.5 eV , 0.024 and 2.51, respectively. Hall measurements confirmed that the films are n-type. The NO2 sensing characteristics of the SnO2:WO3 sensors were studied with various temperatures and NO2 gas concentrations. Both thin film and bulk sensors showed maximum sensitivity at temperature of 250 oC. Thin film sensors showed enhanced response in comparison to that of pellets.

Low-Temperature Synthesis and Gas Sensing Properties of Anatase TiO2 Thin Films

2011 ◽  
Vol 492 ◽  
pp. 300-303
Author(s):  
Fu Jian Ren ◽  
Yi Sun ◽  
Liang Huang ◽  
Yun Han Ling ◽  
Jia You Feng
Keyword(s):  
Thin Films ◽  
Deposition Temperature ◽  
Gas Sensing ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force ◽  
Gas Sensing Properties ◽  
Gas Response

Crystalline anatase TiO2thin films were obtained on glass substrates at 60°C, 75°C and 90°C, respectively, by liquid phase deposition (LPD) method without subsequent heat treatment. X-ray diffraction (XRD), atomic force microscopy (AFM) and UV-Vis spectrophotometer were used to characterize the as-synthesized TiO2thin films. The H2sensing properties of the TiO2thin films based sensors were investigated. The results show that the gas sensors signal Ra/Rg (Ra: resistance in air, Rg: resistance in a sample gas) decreases with the increasing deposition temperature. The TiO2thin films obtained at deposition temperature of 60°C exhibited the maximum H2gas response at 350°C, and the magnitude of the sensor signal and the response time for 500ppm H2was 1.25 and 17s, respectively.

Effect of film thickness on gas sensing properties of sprayed WO3 thin films

2017 ◽  
Vol 41 (20) ◽  
pp. 11807-11816 ◽  
Author(s):  
Rhushikesh Godbole ◽  
V. P. Godbole ◽  
P. S. Alegaonkar ◽  
Sunita Bhagwat
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Properties ◽  
Film Thickness ◽  
Gas Sensing ◽  
Sensing Properties ◽  
Thin Film Sensors ◽  
Gas Sensing Properties ◽  
Property Performance ◽  
Wo3 Thin Films

This study correlates thicknesses, morphology, electrical properties with gas-sensing capability of WO3 thin-film sensors which contributes to understanding of property-performance relationship.

scholarly journals Optical, Structural and Gas Sensing Studies on Tin Oxide Thin Films

2019 ◽  
Vol 31 (8) ◽  
pp. 1805-1808
Author(s):  
Rajesh Kumar ◽  
Swati Chawla
Keyword(s):  
Thin Films ◽  
Tin Oxide ◽  
Hydrogen Sulphide ◽  
Gas Sensing ◽  
Oxide Thin Films ◽  
Hydrocarbon Gases ◽  
Glass Substrates ◽  
Sensing Applications ◽  
Gas Sensing Properties ◽  
Evaporation Technique

In this paper, pure and copper doped tin oxide thin films were grown on glass substrates by thermal evaporation technique for gas sensing applications. Optical, structural and gas sensing properties were investigated for their application for gas sensing applications. The thickness of the samples was kept about 300 nm. The films were annealed at 400 ºC for 4 h in the presence of air. The gas sensing studies were carried out for hydrogen sulphide and ethanol gas. The sensitivity was quite high for hydrogen sulphide gas but little sensitivity towards hydrocarbon gases.

Polyaniline/SnO2 Nanocomposite Sensor for NO2 Gas Sensing at Low Operating Temperature

2015 ◽  
Vol 14 (04) ◽  
pp. 1550011 ◽  
Author(s):  
A. Sharma ◽  
M. Tomar ◽  
V. Gupta ◽  
A. Badola ◽  
N. Goswami
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Sensing Properties ◽  
Response Recovery ◽  
Transmission Electron ◽  
Gas Sensing Properties

In this paper gas sensing properties of 0.5–3% polyaniline (PAni) doped SnO 2 thin films sensors prepared by chemical route have been studied towards the trace level detection of NO 2 gas. The structural, optical and surface morphological properties of the PAni doped SnO 2 thin films were investigated by performing X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Raman spectroscopy measurements. A good correlation has been identified between the microstructural and gas sensing properties of these prepared sensors. Out of these films, 1% PAni doped SnO 2 sensor showed high sensitivity towards NO 2 gas along with a sensitivity of 3.01 × 102 at 40°C for 10 ppm of gas. On exposure to NO 2 gas, resistance of all sensors increased to a large extent, even greater than three orders of magnitude. These changes in resistance upon removal of NO 2 gas are found to be reversible in nature and the prepared composite film sensors showed good sensitivity with relatively faster response/recovery speeds.

scholarly journals Chemically synthesized PbS Nano particulate thin films for a rapid NO2 gas sensor

2016 ◽  
Vol 34 (1) ◽  
pp. 204-211 ◽  
Author(s):  
Vishal V. Burungale ◽  
Rupesh S. Devan ◽  
Sachin A. Pawar ◽  
Namdev S. Harale ◽  
Vithoba L. Patil ◽  
...  
Keyword(s):  
Thin Films ◽  
Gas Sensor ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Gas Sensitivity ◽  
Silar Method ◽  
Layer Adsorption ◽  
Gas Sensing Properties

AbstractRapid NO2 gas sensor has been developed based on PbS nanoparticulate thin films synthesized by Successive Ionic Layer Adsorption and Reaction (SILAR) method at different precursor concentrations. The structural and morphological properties were investigated by means of X-ray diffraction and field emission scanning electron microscope. NO2 gas sensing properties of PbS thin films deposited at different concentrations were tested. PbS film with 0.25 M precursor concentration showed the highest sensitivity. In order to optimize the operating temperature, the sensitivity of the sensor to 50 ppm NO2 gas was measured at different operating temperatures, from 50 to 200 °C. The gas sensitivity increased with an increase in operating temperature and achieved the maximum value at 150 °C, followed by a decrease in sensitivity with further increase of the operating temperature. The sensitivity was about 35 % for 50 ppm NO2 at 150 °C with rapid response time of 6 s. T90 and T10 recovery time was 97 s at this gas concentration.

scholarly journals V2O5 Thin Films as Nitrogen Dioxide Sensors

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 759
Author(s):  
Krystyna Schneider ◽  
Wojciech Maziarz
Keyword(s):  
Thin Films ◽  
Nitrogen Dioxide ◽  
Gas Sensing ◽  
Optical Transmittance ◽  
Fused Silica ◽  
X Ray Diffraction ◽  
Gas Sensing Properties ◽  
Oxygen Gas ◽  
V2o5 Thin Films ◽  
Phase Characterization

V2O5 thin films were deposited onto insulating support (either fused silica or alumina) by means of rf reactive sputtering from a metallic vanadium target. Argon-oxygen gas mixtures of different compositions controlled by the flow rates were used for sputtering. X-ray diffraction at glancing incidence (GIXD) and Scanning Electronic Microscopy (SEM) were used for structural and phase characterization. Optical transmittance and reflectance spectra were recorded with a Lambda 19 Perkin-Elmer double spectrophotometer. Thickness of the films was determined from the profilometry. It has been confirmed by GIXD that the deposited films are composed of V2O5 phase. The estimated optical band gap was ca. 2.5 eV. The gas sensing properties of V2O5 thin films were investigated at RT-690 K towards NO2 gas of 0–20 ppm. The results indicated that material exhibited good response and reversibility towards nitrogen dioxide.

A Formaldehyde Gas Sensor Based on Zinc Doped Lanthanum Ferrite

2013 ◽  
Vol 873 ◽  
pp. 304-310 ◽  
Author(s):  
Jin Zhang ◽  
Yu Min Zhang ◽  
Chang Yi Hu ◽  
Zhong Qi Zhu ◽  
Qing Ju Liu
Keyword(s):  
Gas Sensing ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Sensing Properties ◽  
Transmission Electron ◽  
Lanthanum Ferrite ◽  
Gas Sensing Properties ◽  
Recovery Times ◽  
Response And Recovery ◽  
Sensing Characteristics

The gas-sensing properties of zinc doped lanthanum ferrite (Zn-LaFeO3) compounds for formaldehyde were investigated in this paper. Zn-LaFeO3 powders were prepared using sol-gel method combined with microwave chemical synthesis. The powders were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The formaldehyde gas-sensing characteristics for the sample were examined. The experimental results indicate that the sensor based on the sample Zn-LaFeO3 shows excellent gas-sensing properties to formaldehyde gas. At the optimal operating temperature of 250°C, the sensitivity of the sensor based on LaFe0.7Zn0.3O3 to 100ppm formaldehyde is 38, while to other test gases, the sensitivity is all lower than 20. The response and recovery times for the sample to formaldehyde gas are 100s and 100s, respectively.

Effects on Structural, Electronic Transport & Optical Properties of Doped & Undoped ZnTe Thin Films for CdTe/CdS Solar Cells

2012 ◽  
Vol 510-511 ◽  
pp. 89-97
Author(s):  
G.H. Tariq ◽  
M. Anis-ur-Rehman
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Growth Parameters ◽  
Optical Measurements ◽  
X Ray Diffraction ◽  
Contact Materials ◽  
X Ray ◽  
Glass Substrates ◽  
Evaporation Technique ◽  
Znte Thin Films

To overcome the naturally existing Schottky barrier problem between p-CdTe and any metal, an intermediate semiconductor thin buffer layer is a better choice prior to the final metallization for contact. Among many investigated back contact materials the ZnTe is suitable as a buffer layer. ZnTe thin films were deposited onto glass substrates by the thermal evaporation technique under vacuum ~2×10-5mbar. Undoped ZnTe thin films are highly resistive, extrinsic doping of Cu was made to improve the electrical conductivity. Films were doped by immersing in Cu NO32.5H2O solutions for Cu doping. To optimize the growth parameters the prepared films were characterized using various techniques. The structural analysis of these films was performed by X-ray diffraction (XRD) technique and optical transmission. X-ray diffraction identified the phases present in these films and also observed that the prepared films were polycrystalline. Also the spectral dependence of absorption coefficient was determined from spectrophotometer. Energy band gap index were calculated from obtained optical measurements data.

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