scholarly journals Influence of Oxygen Vacancy Behaviors in Cooling Process on Semiconductor Gas Sensors: A Numerical Analysis

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3929 ◽  
Author(s):  
Jianqiao Liu ◽  
Wanqiu Wang ◽  
Zhaoxia Zhai ◽  
Guohua Jin ◽  
Yuzhen Chen ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Oxygen Vacancy ◽  
Diffusion Equation ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Cooling Process ◽  
Proposed Model ◽  
Vacancy Model ◽  
Vacancy Distribution ◽  
Semiconductor Gas Sensors

The influence of oxygen vacancy behaviors during a cooling process in semiconductor gas sensors is discussed by the numerical analysis method based on the gradient-distributed oxygen vacancy model. A diffusion equation is established to describe the behaviors of oxygen vacancies, which follows the effects of diffusion and exclusion in the cooling process. Numerical analysis is introduced to find the accurate solutions of the diffusion equation. The solutions illustrate the oxygen vacancy distribution profiles, which are dependent on the cooling rate as well as the temperature interval of the cooling process. The gas-sensing characteristics of reduced resistance and response are calculated. Both of them, together with oxygen vacancy distribution, show the grain size effects and the re-annealing effect. It is found that the properties of gas sensors can be controlled or adjusted by the designed cooling process. The proposed model provides a possibility for sensor characteristics simulations, which may be beneficial for the design of gas sensors. A quantitative interpretation on the gas-sensing mechanism of semiconductors has been contributed.

scholarly journals Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics

Sensors ◽  
2017 ◽  
Vol 17 (8) ◽  
pp. 1852 ◽  
Author(s):  
Jianqiao Liu ◽  
Yinglin Gao ◽  
Xu Wu ◽  
Guohua Jin ◽  
Zhaoxia Zhai ◽  
...  
Keyword(s):  
Oxygen Vacancy ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Vacancy Distribution ◽  
Semiconductor Gas Sensors ◽  
Sensing Characteristics

scholarly journals Numerical Analysis of Oxygen Vacancy Distribution in Semiconductor Gas Sensors in the Cooling Process Based on the Model of Gradient-Distributed Oxygen Vacancies

2019 ◽  
Vol 26 (2) ◽  
pp. 133-138
Author(s):  
Jianqiao LIU ◽  
Zhaoxia ZHAI ◽  
Guohua JIN ◽  
Liting WU ◽  
Fengjiao GAO ◽  
...  
Keyword(s):  
Diffusion Equation ◽  
Oxygen Vacancies ◽  
Numerical Solutions ◽  
Gas Sensing ◽  
Annealing Process ◽  
Cooling Process ◽  
Transient Stage ◽  
Vacancy Distribution ◽  
Three Stages ◽  
Sensing Characteristics

The oxygen vacancies (VO) play an essential role in the gas-sensing mechanism of semiconductor devices. A diffusion equation is established to describe the VO behaviors during a cooling process based on the model of gradient-distributed oxygen vacancies. Numerical solutions of the diffusion equation are found to illustrate the VO distribution in grains. The gradient of VO distribution is of negative dependence on the cooling rate, which also influences the average VO density in the depletion layer. The migration of oxygen vacancies in cooling process could be interrupted by quenching and it is restarted by the re-annealing process. The VO distributing process is illustrated by three stages from initial uniform distribution to final gradient profile via a transient stage. The influence of VO distribution on gas-sensing characteristics of semiconductor grains is discussed. Potential opportunities are found to control the gas sensor characteristics by a designed annealing process.

Time-dependent oxygen vacancy distribution and gas sensing characteristics of tin oxide gas sensitive thin films

2010 ◽  
Vol 150 (1) ◽  
pp. 330-338 ◽  
Author(s):  
Jianqiao Liu ◽  
Shuping Gong ◽  
Qiuyun Fu ◽  
Yi Wang ◽  
Lin Quan ◽  
...  
Keyword(s):  
Thin Films ◽  
Oxygen Vacancy ◽  
Tin Oxide ◽  
Gas Sensing ◽  
Time Dependent ◽  
Vacancy Distribution ◽  
Sensing Characteristics

Nanocrystalline Materials as Potential Gas Sensing Elements

1997 ◽  
Vol 501 ◽  
Author(s):  
G. S. V. Coles ◽  
G. Williams
Keyword(s):  
Gas Sensors ◽  
Nanocrystalline Materials ◽  
Tin Dioxide ◽  
Gas Sensing ◽  
Electronics Industry ◽  
Laser Evaporation ◽  
Foreseeable Future ◽  
Specific Context ◽  
Semiconductor Gas Sensors ◽  
Cost Of Materials

ABSTRACTSensors and Transducers, and in the specific context of this paper gas sensors, are currently amongst the largest growth areas in the modem electronics industry and this seems likely to continue for the foreseeable future. Nanocrystalline materials posses many properties that could make them ideal as potential gas sensing elements with many advantages over their microcrystalline counterparts. Most importantly these include increased surface area coupled with reduced sintering temperatures and times. However, it should also be noted that there are several disadvantages including the comparatively high cost of materials and increased electrical resistance.This paper reviews the operating mechanisms of semiconductor gas sensors and the possible advantages of using nano sized powders to produce gas sensitive devices. Results are presented which have been obtained from several materials produced by laser evaporation including alumina (Al2O3), zirconia (ZrO2), and tin dioxide (SnO2) in contaminated atmospheres incorporating carbon monoxide, hydrogen and methane.

Pure and Pr-doped Ce4W9O33 with superior hydroxyl scavenging ability: Humidity-independent oxide chemiresistors

2021 ◽  
Author(s):  
Jun-Sik Kim ◽  
Ki Beom Kim ◽  
Huayao Li ◽  
Chan Woong Na ◽  
Kyeorei Lim ◽  
...  
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Oxide Semiconductor ◽  
Semiconductor Gas Sensors ◽  
First Time ◽  
Sensing Characteristics ◽  
Standing Problem

Water poisoning has been a long-standing problem in oxide semiconductor gas sensors. Herein, for the first time, we report that pure and Pr-doped Ce4W9O33 provide humidity-independent gas sensing characteristics. The...

scholarly journals Unexpected Selectivity of UV Light Activated Metal-Oxide-Semiconductor Gas Sensors by Two Different Redox Processes

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Wenting Li ◽  
Gu Xu
Keyword(s):  
Metal Oxide ◽  
Gas Sensors ◽  
Dynamic Equilibrium ◽  
Uv Light ◽  
Reducing Agents ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Clear Explanation ◽  
Proposed Model ◽  
Semiconductor Gas Sensors

The conflict between the two existing models was resolved, to provide a clear explanation for the unexpected “selectivity” found in UV light activated metal-oxide-semiconductor (MOS) gas sensors during the detection of reducing agents. A new model based on the dynamic equilibrium of adsorbed oxygen concentration was constructed by two types of responses: (1) when the MOS surface is adsorbed with oxygen, the conductance of the sensor increases upon injection of reducing agents (RA) (α-type) and (2) when the MOS surface is not covered by oxygen, the conductance decreases upon injection of RA (β-type). The proposed model was verified by the experiments of ZnO based MOS gas sensors, to reveal the origin of the unexpected “selectivity” found by the optimum intensity, where the current drop, due to the reaction between RA and MOS, which increases with UV power and levels with the reciprocal background current, which decreases with the UV power.

scholarly journals Consideration for Oxygen Adsorption Species on SnO2 Semiconductor Gas Sensors

Proceedings ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 18
Author(s):  
Kengo Shimanoe ◽  
Takaharu Mizukami ◽  
Koichi Suematsu ◽  
Ken Watanabe
Keyword(s):  
Water Vapor ◽  
Gas Sensors ◽  
Gas Sensing ◽  
Oxygen Adsorption ◽  
Sensing Properties ◽  
Gas Sensing Properties ◽  
Semiconductor Gas Sensors ◽  
Adsorption Species

Water vapor is the most important factor to influence on gas sensing properties. […]

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