Surface Science Studies of Metal Oxide Gas Sensing Materials

Tao, Junguang; Batzill, Matthias

doi:10.1007/978-1-4614-5395-6_2

Cited by 8 publications

(8 citation statements)

References 51 publications

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“…the Fermi-level is pushed into the band gap towards the valence band. 38 When the reducing test gas reacts with the adsorbed oxygen species, electrons are released and transferred to the conduction band of SnO 2 which, in turn, reduces the band bending, resulting in the reduction of the potential barrier.…”

Section: Formaldehyde Sensing Propertiesmentioning

confidence: 99%

Influence of Cu doping on the structural, photoluminescence and formaldehyde sensing properties of SnO₂nanoparticles

2014

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Section: Formaldehyde Sensing Propertiesmentioning

confidence: 99%

Influence of Cu doping on the structural, photoluminescence and formaldehyde sensing properties of SnO₂nanoparticles

2014

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“…Similarly, adsorption of LPG constituent molecules at the interface can further reduce conductivity by acting as trap states for conduction electrons [ 5 , 17 , 45 – 47 ]. Specifically for ZnO, the surface assists this continued adsorption of gases due to low surface atomic coordination and high surface energy [ 40 ].…”

Section: Results and Discussion For Liquid Petroleum Gas Sensorsmentioning

confidence: 99%

“…on the surface. As a result there exists abundant surface states on the ZnO surface [40–42]. The surface states form a potential barrier on the surface, which is almost independent of the work function of the metal due to Fermi level pinning [10,40].…”

Section: Current-voltage Characterization Of Devicesmentioning

confidence: 99%

Effect of Embedded Pd Microstructures on the Flat-Band-Voltage Operation of Room Temperature ZnO-Based Liquid Petroleum Gas Sensors

Ali

Thompson

Jasim

et al. 2013

Sensors

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Three methods were used to fabricate ZnO-based room temperature liquid petroleum gas (LPG) sensors having interdigitated metal-semiconductor-metal (MSM) structures. Specifically, devices with Pd Schottky contacts were fabricated with: (1) un-doped ZnO active layers; (2) Pd-doped ZnO active layers; and (3) un-doped ZnO layers on top of Pd microstructure arrays. All ZnO films were grown on p-type Si(111) substrates by the sol-gel method. For devices incorporating a microstructure array, Pd islands were first grown on the substrate by thermal evaporation using a 100 μm mesh shadow mask. We have estimated the sensitivity of the sensors for applied voltage from –5 to 5 V in air ambient, as well as with exposure to LPG in concentrations from 500 to 3,500 ppm at room temperature (300 K). The current-voltage characteristics were studied and parameters such as leakage current, barrier height, reach-through voltage, and flat-band voltage were extracted. We include contributions due to the barrier height dependence on the electric field and tunneling through the barrier for the studied MSM devices. The Pd-enhanced devices demonstrated a maximum gas response at flat-band voltages. The study also revealed that active layers consisting of Pd microstructure embedded ZnO films resulted in devices exhibiting greater gas-response as compared to those using Pd-doped ZnO thin films or un-doped active layers.

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“…When O 2 molecules are adsorbed on the surface of metal oxides, they would extract electrons from the conduction band and trap the electrons at the surface in the form of ions. This will lead to a band bending and an electron-depleted region [ 76 , 106 ]. Reaction of these oxygen species with reducing gases or a competitive adsorption and replacement of the adsorbed oxygen by other molecules decreases and can reverse the band bending, resulting in an increased conductivity [ 107 , 108 , 109 ].…”

Section: Nanomaterial-based Approaches For Detection Of Acetonementioning

confidence: 99%

Sensing Technologies for Detection of Acetone in Human Breath for Diabetes Diagnosis and Monitoring

et al. 2018

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The review describes the technologies used in the field of breath analysis to diagnose and monitor diabetes mellitus. Currently the diagnosis and monitoring of blood glucose and ketone bodies that are used in clinical studies involve the use of blood tests. This method entails pricking fingers for a drop of blood and placing a drop on a sensitive area of a strip which is pre-inserted into an electronic reading instrument. Furthermore, it is painful, invasive and expensive, and can be unsafe if proper handling is not undertaken. Human breath analysis offers a non-invasive and rapid method for detecting various volatile organic compounds thatare indicators for different diseases. In patients with diabetes mellitus, the body produces excess amounts of ketones such as acetoacetate, beta-hydroxybutyrate and acetone. Acetone is exhaled during respiration. The production of acetone is a result of the body metabolising fats instead of glucose to produce energy. There are various techniques that are used to analyse exhaled breath including Gas Chromatography Mass Spectrometry (GC–MS), Proton Transfer Reaction Mass Spectrometry (PTR–MS), Selected Ion Flow Tube-Mass Spectrometry (SIFT–MS), laser photoacoustic spectrometry and so on. All these techniques are not portable, therefore this review places emphasis on how nanotechnology, through semiconductor sensing nanomaterials, has the potential to help individuals living with diabetes mellitus monitor their disease with cheap and portable devices.

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Surface Science Studies of Metal Oxide Gas Sensing Materials

Cited by 8 publications

References 51 publications

Influence of Cu doping on the structural, photoluminescence and formaldehyde sensing properties of SnO₂nanoparticles

Influence of Cu doping on the structural, photoluminescence and formaldehyde sensing properties of SnO₂nanoparticles

Effect of Embedded Pd Microstructures on the Flat-Band-Voltage Operation of Room Temperature ZnO-Based Liquid Petroleum Gas Sensors

Sensing Technologies for Detection of Acetone in Human Breath for Diabetes Diagnosis and Monitoring

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Surface Science Studies of Metal Oxide Gas Sensing Materials

Cited by 8 publications

References 51 publications

Influence of Cu doping on the structural, photoluminescence and formaldehyde sensing properties of SnO2nanoparticles

Influence of Cu doping on the structural, photoluminescence and formaldehyde sensing properties of SnO2nanoparticles

Effect of Embedded Pd Microstructures on the Flat-Band-Voltage Operation of Room Temperature ZnO-Based Liquid Petroleum Gas Sensors

Sensing Technologies for Detection of Acetone in Human Breath for Diabetes Diagnosis and Monitoring

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Influence of Cu doping on the structural, photoluminescence and formaldehyde sensing properties of SnO₂nanoparticles

Influence of Cu doping on the structural, photoluminescence and formaldehyde sensing properties of SnO₂nanoparticles