Modelling and simulation of thin film semiconductor metal oxide gas sensor response

Download

index.pdf

Date

2019

Author

Atman, Berkan

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

458
views

253
downloads

Metal oxide based semiconductor gas sensors have attracted attention due to their superior properties. Over past five decades an extensive research had been conducted for understanding the true nature of the sensing mechanism, most suitable material and optimum operating conditions. SnO2 has received over years a great deal of attention as it can meet most of the necessary requirements of a gas sensor. Although commercially available gas sensors based on tin oxide are available and plenty of studies has been devoted to tin oxide based gas sensors, still there are many questions remained unanswered or have unsatisfactory explanations. In this work by developing a mathematical model with a comprehensive approach it is aimed to address some of those questions in terms of effects of diffusion, kinetic parameters, film thickness on complex dynamic behavior of the n- type semiconductor gas sensors in an environment being CO-air mixture. Furthermore, the constructed model provides an opportunity to analyze response/recovery dynamics in terms of electrical current obtained from current density distribution. The results of the simulations based on the transient model shows that increasing the thickness significantly reduces the sensitivity whereas slightly decreases the response time. The effect of diffusion on concentration profiles and current density distributions and their consequences are extensively discussed. Elevated temperature resulted in lower response and recovery times of the sensors. The temperature dependence of sensitivity was explained in terms of the competitive effect of activation energies of the surface kinetics and diffusion effect.

Subject Keywords

Thin films., Keywords: Semiconductor Gas Sensor, Mathematical Modelling, CO Sensing, Tin Oxide, Dynamic Response.

URI

http://etd.lib.metu.edu.tr/upload/12624022/index.pdf
https://hdl.handle.net/11511/44234

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Experimental investigation of the effect of CNT addition on the strength of CFRP curved composite beams Arca, M.A.; Uyar, I.; Çöker, Demirkan (2015-01-01) Carbon nanotubes (CNT) have been attracting attention as a toughening material in composite matrix due to their excellent mechanical properties. However, superior properties of CNTs have not yet been realized in the strengthening of composites against fracture. This study focuses on investigating the effect of CNT variation in the epoxy resin on the strength of curved composite beams. Specimens are [0/90] fabric carbon/epoxy composite laminates manufactured by hand layup technique 3 % wt CNT fractions in th...
Experimental Investigation of the Effect of CNT addition on the strength of CFRP Curved Composite Beams, Miray, Arca; Uyar, Imren; Çöker, Demirkan (null, Springer, 2015-01-01) Carbon nanotubes (CNT) have been attracting attention as a toughening material in composite matrix due to their excellent mechanical properties. However, superior properties of CNTs have not yet been realized in the strengthening of composites against fracture. This study focuses on investigating the effect of CNT variation in the epoxy resin on the strength of curved composite beams. Specimens are [0/90] fabric carbon/epoxy composite laminates manufactured by hand layup technique 3 % wt CNT fractions in th...
Investigation of bismuth doped bioglass/graphene oxide nanocomposites for bone tissue engineering Pazarçeviren, Ahmet Engin; Tezcaner, Ayşen; Keskin, Dilek; Evis, Zafer (2018-03-01) In this study, bismuth doped 45S5 nanobioactive bioglass (nBG) and graphene oxide (GO) nanocomposites were developed and characterized in terms of microstructural, mechanical, bioactivity and biological properties. Bismuth (Bi) - doped nBG was synthesized by sol-gel method and sintered at 600 degrees C for 2 h. Nanosized GO was homogeneously mixed with Bi doped bioglass at various ratios to prepare nanocomposites. Addition of Bi increased the density of nBG samples while a considerable decrease in density w...
Formation and characterization of infrared absorbing copper oxide surfaces Arslan, Burcu; Erdogan, Metehan; Karakaya, İshak (2017-04-30) Copper oxide formation has been investigated to combine the advantages of producing different size and shapes of coatings that possess good light absorbing properties. An aqueous blackening solution was investigated and optimum composition was found as 2.5 M NaOH and 0.225 M NaClO to form velvet copper oxide films. A two-step oxidation mechanism was proposed for the blackening process by carefully examining the experimental results. Formation of Cu2O was observed until the entire copper surface was covered ...
Numerical modeling of visco-elasto-plastic hygro-thermal stresses and the effects of operating conditions on the mechanical degradation of PEFC membranes Mehrtash, Mehdi; Tarı, İlker; YEŞİLYURT, SERHAT (2018-08-31) Durability of membranes is one of the concerns for widespread commercialization of polymer electrolyte fuel cells. Effects of membrane swelling on the durability pose important challenges for the fabrication of the catalyst-coated membrane. This study provides insight into vulnerable locations of the membrane under hygrothermal loading, mechanical loading due to clamping and realistic conditions where a combination of both of these loadings are imposed. With a half rib-channel model, we simulate a polymer e...

Citation Formats

B. Atman, “Modelling and simulation of thin film semiconductor metal oxide gas sensor response,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Chemical Engineering., Middle East Technical University, 2019.