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Improvement Of Gas Sensing Property Modified By Plasma Study Of Metal Oxide Materials

Posted on:2019-02-03Degree:MasterType:Thesis
Country:ChinaCandidate:H S WangFull Text:PDF
GTID:2428330566484400Subject:Electronic Science and Technology
Abstract/Summary:PDF Full Text Request
Metal oxide semiconductors sensing materials has become the research hotspot because of its low cost and easy working circuits.So,improving its sensing performance is deadly needed.Plasma technology is widely used in areas of materials surface treatment and improvement etc.In this paper,plasma technology is applied in improving the properties of metal oxide gas sensor,ZnO,In2O3 and NiO materials modified by oxygen and hydrogen plasma is prepared as the main gas sensing materials to analyze the sensitive improving mechanisms.The main contents are as follows:ZnO,In2O3 and NiO nanofibers are prepared by the electrospinning method before the treatment of oxygen and hydrogen plasma at the same parameter settings.XRD,SEM,BET and XPS were used to characterize the materials modified before and after by plasma.Gas sensitive properties to acetone,alcohol,methanol,formaldehyde,benzene and ammonium of the materials is tested using the static gas distribution system.Through the testing result,ZnO,In2O3 materials modified by oxygen plasma showed great improvement in gas sensing,especially to acetone.Meanwhile all three materials showed better performance in gas sensing after modifying by hydrogen plasma.Combined with the characterization results of the four characterizing methods and the results of static gas sensor testing system,the horizontal comparison data of ZnO,In2O3 and NiO materials modified before and after by plasma have been listed,such as the materials' grain size,morphology,specific surface area,pore size,specific pore volume,ratio of oxygen content,optimize working temperature,response values,selectivity,etc.According to the conclusion of the comparison,the affection mechanism of the plasma treatment to the three metal oxide materials been discussed.The affection mechanism is mainly explained by two aspects: the first aspect is grain size decreasing,response values of n-type materials obviously increased after plasma treatment,on the contrary,response values of p-type materials remained after the same treatment.The other aspect is changing the content of adsorbed oxygen.Rising the specific surface area and specific pore volume of the materials and changing the oxygen vacancies content are the two ways to realize the control of absorbed oxygen by plasma treatment.The improvement of selectivity is related to the polarity change of the material surface caused by plasma.
Keywords/Search Tags:Metal oxide materials, Gas Sensor, Plasma, Gas Sensitive Mechanism
PDF Full Text Request
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