scholarly journals AZO-Based ZnO Nanosheet MEMS Sensor with Different Al Concentrations for Enhanced H2S Gas Sensing

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3377
Author(s):  
Yempati Nagarjuna ◽  
Jun-Cong Lin ◽  
Sheng-Chang Wang ◽  
Wen-Tse Hsiao ◽  
Yu-Jen Hsiao
Keyword(s):  
Zinc Oxide ◽  
Gas Sensing ◽  
Growth Time ◽  
Optimal Conditions ◽  
Gas Concentration ◽  
Zno Nanostructure ◽  
Mems Sensor ◽  
Different Temperatures ◽  
Micro Electromechanical System ◽  
Different Gases

The properties of H2S gas sensing were investigated using a ZnO nanostructure prepared with AZO (zinc oxide with aluminium) and Al surfaces which were developed on a MEMS (Micro Electromechanical System) device. Hydrothermal synthesis was implemented for the deposition of the ZnO nanostructure. To find the optimal conditions for H2S gas sensing, different ZnO growth times and different temperatures were considered and tested, and the results were analysed. At 250 °C and 90 min growth time, a ZnO sensor prepared with AZO and 40 nm Al recorded an 8.5% H2S gas-sensing response at a 200 ppb gas concentration and a 14% sensing response at a gas concentration of 1000 ppb. The dominant sensing response provided the optimal conditions for the ZnO sensor, which were 250 °C temperature and 90 min growth time. Gas sensor selectivity was tested with five different gases (CO, SO2, NO2, NH3 and H2S) and the sensor showed great selectivity towards H2S gas.

scholarly journals Detection of Emanated Light at the Modified Clad Region (Sno2) of the Optical Fiber for Methanol Gas Sensing

2020 ◽  
Vol 8 (5) ◽  
pp. 3327-3332
Keyword(s):  
Optical Fiber ◽  
Room Temperature ◽  
Gas Sensing ◽  
Output Intensity ◽  
Gas Sensitivity ◽  
Radiation Mode ◽  
Gas Concentration ◽  
Fiber Mode ◽  
Modified Surface ◽  
Different Gases

A leakage detecting sensor (radiation mode (or) double fiber mode) is proposed to monitor the light rays propagates from the surface of the modified clad region (SnO2 ) of the optical fiber. The output intensity increases and decreases for the varying gas concentration (0-500 ppm) with the presence of different gases (methanol, ethanol, acetone and ammonia) at room temperature. The received output intensity from the clad modified surface increases for ammonia and methanol, whereas, it decreases for acetone and ethanol gases for the increase in the gas concentration. However, in the transmitting mode (single fiber mode) the output light intensity decreases for all the gases with varying gas concentration. The output gas sensitivity of the proposed sensor (double fiber mode) is compared with the transmitting mode sensor and the sensor shows superior response for methanol over other gases. The dynamic characteristics of the sensor are reported.

scholarly journals Selective gas detection using Mn3O4/WO3 composites as a sensing layer

2019 ◽  
Vol 10 ◽  
pp. 1423-1433 ◽  
Author(s):  
Yongjiao Sun ◽  
Zhichao Yu ◽  
Wenda Wang ◽  
Pengwei Li ◽  
Gang Li ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Hydrogen Sulfide ◽  
Gas Sensing ◽  
Gas Detection ◽  
Facile Hydrothermal Method ◽  
Potential Applications ◽  
Different Temperatures ◽  
Different Gases ◽  
Sensing Performance ◽  
Mn Concentrations

Pure WO3 sensors and Mn3O4/WO3 composite sensors with different Mn concentrations (1 atom %, 3 atom % and 5 atom %) were successfully prepared through a facile hydrothermal method. As gas sensing materials, their sensing performance at different temperatures was systematically investigated for gas detection. The devices displayed different sensing responses toward different gases at specific temperatures. The gas sensing performance of Mn3O4/WO3 composites (especially at 3 atom % Mn) were far improved compared to sensors based on pure WO3, where the improvement is related to the heterojunction formed between the two metal oxides. The sensor based on the Mn3O4/WO3 composite with 3 atom % Mn showed a high selective response to hydrogen sulfide (H2S), ammonia (NH3) and carbon monoxide (CO) at working temperatures of 90 °C, 150 °C and 210 °C, respectively. The demonstrated superior selectivity opens the door for potential applications in gas recognition and detection.

NANOSTRUCTURAL ZnO FABRICATED BY VAPOR-PHASE TRANSPORT IN AIR

2004 ◽  
Vol 18 (02) ◽  
pp. 225-232 ◽  
Author(s):  
C. X. XU ◽  
X. W. SUN ◽  
B. J. CHEN ◽  
C. Q. SUN ◽  
B. K. TAY
Keyword(s):  
Zinc Oxide ◽  
Growth Time ◽  
Zinc Oxide Nanostructures ◽  
X Ray Diffraction ◽  
Vapor Phase Transport ◽  
X Ray ◽  
Zno Nanostructure ◽  
Oxide Nanostructures ◽  
Vapor Liquid Solid Mechanism ◽  
Phase Transport

Nanostructural zinc oxide has been successfully fabricated by heating the mixture of ZnO and graphite powders in air. The growth of these zinc oxide nanostructures with respect to the growing time and temperature has been studied. The morphologies and the crystal structures have been characterized by scanning electronic microscopy and the X-ray diffraction. The results indicated that ZnO nanostructure formed mainly along the crystal orientation [002] on silicon substrate at moderate temperatures. The crystallization was improved by prolonging growth time and the morphologies mainly depended on the distribution of the growth temperature. The growth process was attributed to vapor-liquid-solid mechanism.

scholarly journals Gas Sensing Studies of Tin Oxide Thin Films Annealed at Different Temperatures

2017 ◽  
Vol 9 (2) ◽  
pp. 10
Author(s):  
K. S. Thakare ◽  
S. J. Patil ◽  
R. R. Ahire
Keyword(s):  
Thin Films ◽  
Tin Oxide ◽  
Vapour Deposition ◽  
Gas Sensing ◽  
Physical Vapour Deposition ◽  
Working Temperature ◽  
Gas Sensing Properties ◽  
Different Temperatures ◽  
Gas Response ◽  
Different Gases

Thin films of Tin oxide (SnO<sub>2</sub>) were prepared by physical vapour deposition method. The as-prepared films were further annealed at 300°C, 400°C and 500°C to study the effect of annealing on the physical as well as gas sensing properties of the thin films. Gas sensing performance of annealed SnO<sub>2</sub> thin films was studied for different gases having different concentrations at working temperature of 250°C. Significantly, gas response changes for SnO<sub>2</sub> samples annealed at different temperatures, which is discussed herein.

Ammonia Gas Detection Using Fabricated Zinc Oxide (ZnO) Nanoparticles on Glass Tube Substrates

2018 ◽  
Vol 775 ◽  
pp. 266-271 ◽  
Author(s):  
Kurt Brian Daine B. Punzalan ◽  
Franz Kevin B. Manalo ◽  
Emmanuel A. Florido
Keyword(s):  
Zinc Oxide ◽  
Gas Sensing ◽  
Linear Trend ◽  
Glass Tube ◽  
Ammonium Hydroxide ◽  
Zno Films ◽  
Ammonia Gas ◽  
Layer Adsorption ◽  
Different Temperatures ◽  
Silar Technique

This study aimed to determine the ammonia (NH3) gas sensing ability of zinc oxide (ZnO) films deposited on glass tube substrates via successive ionic layer adsorption and reaction (SILAR) technique. The fabricated films were annealed at different temperatures. The sensor films were exposed to different volumes of ammonium hydroxide (NH4OH), converted to parts per million (ppm). The change in voltage from concentrations 595ppm up to 1189ppm exhibited a linear trend. However, no trend was revealed in concentrations 2378ppm and 3964ppm due to film saturation. Results showed that the films annealed at 250 °C, 300 °C, 350 °C, and 400 °C presented sensitivities of 2.7×10-4V/ppm, 1.0×10-4V/ppm, 2.3×10-4V/ppm, and 1.5×10-4V/ppm with R2values of 0.997, 0.994, 0.904, 0.999 and resolutions of 3.7 ppm/mV, 9.9 ppm/mV, 4.4 ppm/mV, and 6.6 ppm/mV, respectively. Furthermore, this research study had proven that high quality gas sensors may be fabricated at a lower cost.

TEMPERATURE DEPENDENCE OF HOMOGENEOUS ANATASE-PHASED TiO2 FILMS CHARACTERIZATION AND GAS-SENSING BEHAVIORS

2020 ◽  
pp. 2050029
Author(s):  
V. GOPALA KRISHNAN ◽  
P. ELANGO
Keyword(s):  
Gas Sensing ◽  
Gas Concentration ◽  
Standard Data ◽  
Reducing Gas ◽  
Primary Element ◽  
Nebulizer Spray Pyrolysis ◽  
Amorphous Nature ◽  
Different Temperatures ◽  
Optical Profilometer ◽  
Nebulizer Spray

Anatase-phased TiO2 films were prepared at different temperatures (350, 400, 450 and 500∘C) using automated nebulizer spray pyrolysis (ANSP) method. The structural study (XRD) revealed the amorphous nature at 350∘C and remaining samples (400, 450 and 500∘C) show the tetragonal structure with 2[Formula: see text], 38.43, 48.49 and 55.54 corresponding to (101), (004), (200) and (105) reflected planes and it is well fitted with standard data. The compositional XPS analysis confirmed the core level primary element of Ti 2p, O 1s and valance band (VB) of Ti 3p, Ti 3s, O 2s peaks in the prepared samples. The 3D optical profilometer has shown that the thickness of the prepared films was decreased by increase in temperature. The AFM study exhibited average roughnesses (Ra) of the prepared films such as 0.058, 0.147, 0.176 and 0.194[Formula: see text]nm, respectively. The surface morphological study of FESEM has shown the cracked uneven distributed nature (350∘C) turn into evenly distributed closed packed agglomerated particles by the influence of temperature. The oscillating nature of transmittance (%) with redshift of the sharp absorption edge was observed in UV–Vis–NIR spectrophotometer and found the bandgap value about 3.58[Formula: see text]eV to 3.33[Formula: see text]eV through Tauc’s relation. The gas-sensing behavior has shown better response to C2H6O reducing gas at 300∘C operating temperature with 150 ppm gas concentration.

scholarly journals Au Doping ZnO Nanosheets Sensing Properties of Ethanol Gas Prepared on MEMS Device

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 945
Author(s):  
Yempati Nagarjuna ◽  
Yu-Jen Hsiao
Keyword(s):  
Gas Sensing ◽  
Micro Electro Mechanical System ◽  
Operating Conditions ◽  
Structural Morphology ◽  
X Ray ◽  
Zno Nanostructure ◽  
Zno Nanosheets ◽  
Different Temperatures ◽  
Doped Zno ◽  
Mems Device

Sensitivity of the Micro Electro Mechanical System (MEMS) device ZnO nanosheets sensor and the Au doped ZnO nanosheets sensor has been investigated. The ZnO samples have been prepared using Hydrothermal synthesis at 90 °C. The prepared ZnO nanostructure is tested for structural morphology and crystallinity properties. The elemental analysis of the ZnO sample and Au–ZnO samples are tested by using Energy Dispersive X-ray Spectroscopy (EDS) spectrum analysis. MEMS device microheater is designed and prepared for testing the sensitivity of Ethanol gas. Thermal properties of the MEMS microheater is studied for better gas testing at different temperatures. Both the ZnO nanosheets sensor and Au doped ZnO nanosheets sensor are tested using Ethanol gas, and the gas concentrations are taken to be 15, 30, 45, and 60 ppm at 300 °C. The gas sensing response of pure ZnO nanosheets tested for ethanol gas at 60 ppm showed 20%, while the Au–ZnO nanosheets showed 35%, which is increased by 15% at similar operating conditions.

scholarly journals Synthesis of Zinc Oxide Nanostructure by Chemical Bath Deposition (CBD) Method: Influence of Growth Time towards Nanostructure Characteristics

2019 ◽  
Vol 8 (4) ◽  
pp. 6891-6896
Keyword(s):  
Zinc Oxide ◽  
Chemical Bath Deposition ◽  
Indium Tin Oxide ◽  
Morphological Changes ◽  
Structural Characteristics ◽  
Ultra Violet ◽  
Vital Role ◽  
Growth Time ◽  
Zno Nanostructures ◽  
Zno Nanostructure

Growth of zinc oxide (ZnO) nanostructure on seeded indium tin oxide (ITO) via chemical bath deposition were presented in this study. Growth time is believed to have vital role in order to control the physical (morphology), optical and structural characteristics of ZnO nanostructures. Several growth time of ZnO nanostructure were varied (1 H – 3.5 H) as the purpose to investigate its effect towards the growth of ZnO nanostructures, as well as their characteristics. In this study, the influence of growth time was determined using field emission scanning electron microscope (FESEM), ultra-violet visible spectrometer (UV-Vis) and x-ray diffraction (XRD). Based on the results obtained, morphological, optical and structural characteristics of ZnO nanostructure thin films grown at various growth time present different characteristics and properties. According to the results obtained, it is proved that growth time is a vital parameter to control the ZnO nanostructure growing process. ZnO nanostructure morphological changes significantly with the changes of the growing time process. As well as optical properties, the changes of absorbance and transmittance value influence the optical energy band gap of ZnO nanostructure in this study, which is the average value is 3.31 -3.40 eV. The structural characteristic of the ZnO nanostructure also affected significantly with the difference of growth time, where the crystallinity is improved with the longer growth time.

A STUDY ON ENHANCED GAS SENSING APPLICATION THROUGH SPR SENSORS AND PLASMONIC ZNO NANOSTRUCTURE

2021 ◽  
Vol 7 (2) ◽  
Author(s):  
Bindu Swetha Pasuluri ◽  
Radhika Mahankali ◽  
Manga J. ◽  
C Rajeshwari
Keyword(s):  
Zinc Oxide ◽  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Gas Sensing ◽  
Zno Nanostructure ◽  
Metallic Grating ◽  
Plasmonic Nanostructure ◽  
Recent Trends ◽  
Sensing Application

A brief overview of recent trends in Surface Plasmon Resonance (SPR) technology especially for gas sensing is presented. Some novel sensors (metallic grating, MIM, optical fiber) are discussed along with the development of plasmonic nanostructure based on zinc oxide (ZnO) for enhancing sensing application.

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