Study On The Gas-Sensing Characteristic Of Prepared Gd Doped ZnO

In recent years,with the continuous development of society and the progress of science and technology,a large number of high-tech has gradually entered life and production.people have been threatened by various toxic,harmful and combustible gases.Therefore,the research of gas detection technology has been paid much attention.Metal oxide semiconductor gas sensor has the advantages of excellent physical and chemical stability,low cost,excellent sensing performance and so on.It has been widely used in security monitoring,environmental protection,drug inspection,military defense and other fields.ZnO is a wide forbidden band gap semiconductor material,which has a wide range of applications in the fields of optoelectronic devices,field emission devices,sensors,and ultraviolet lasers.It is used as a direct wide band gap semiconductor of group II-VI,with a room temperature gap of about 3.37 eV,and an exciton binding energy as high as 60 meV.Moreover,it has good chemical stability,high electron mobility,and is not easy to decompose at high temperatures.Its particles can be synthesized with various morphologies and structures,which is beneficial to use as a gas sensor for gas sensors.At the same time,it shows good gas sensitivity for most reducing gases.In device applications,improving the sensitivity of sensors has always been an important research topic.The methods to improve the sensitivity of the sensor mainly include the adjustment of the morphology and structure,the incorporation of other elements,the existence of defect vacancies,and the selection of operating temperature.Therefore,this article starts with these aspects to improve sensitivity,and the specific research content is as follows:(1)ZnO nanorods was fabricated on a Si(100)substrate by RF magnetron sputtering.X-ray Diffraction(XRD)and Scanning Electron Microscopy(SEM)were used to characterize the structure and surface morphology of the samples.In view of the fact that the basic sputtering conditions can not realize the arrangement of the spherical protrusions in a stripe array,after the substrate was heated at 450°C,the damascene structure was changed and the stripe array growth of the ZnO vertical substrate bottom was realized.XRD showed that the stripe array was closely related to the orientation of the ZnO(103)crystal plane.Combined with the influence of sputtering power on the growth rate,at low rates,the stripes were not obvious enough,and the array was inhibited by(002)orientation,and at high rates,the interference of(002)crystal plane growth orientation can be eliminated.A high-power,high-rate,high-temperature heating ZnO vertical stripe array was realized along the(103)crystal plane preferential growth structure.This will be a good gas-sensing material for gas sensors.The gas sensitivity test results showed that the nano-array structure was 1.82 times more sensitive than the thin-film mosaic ZnO gas sensor in the constant concentration of acetone vapor,and it has a faster instant signal for detecting acetone and hydrogen.Therefore,the instant response was beneficial to detection.The presence or absence of dangerous gases.(2)With the rare earth element Gd as the doping element,0.5%and 2%Gd-doped ZnO nanostructures were synthesized by the RF magnetron dual-target co-sputtering method.The research was carried out by XRD,SEM,EDX and other characterization methods.The study found that compared with undoped ZnO,Gd-doped ZnO has a uniform surface and a large contact area,and the gaps between nanostructures were uniform and wide.When there was a zinc-rich state,it can provide more reaction sites.The growth orientation was all transformed into a hexagonal wurtzite crystal structure,which changed the energy distribution in all directions.Increasing the forbidden band width introduced impurity energy levels,and the lattice can increase the carrier concentration.Therefore,it is very easy to react with the target gas molecules to enhance the ZnO sensing response.The gas sensor test results showed that the Gd-doped ZnO gas sensor can achieve H₂ response at room temperature.In the detection of exposure to acetone vapor,the doping of Gd greatly improved the sensitivity of pure ZnO as a gas-sensitive material.Therefore,Gd doping was of great significance for enhancing the sensing performance of ZnO gas sensors,and had broad application prospects in detecting harmful gases.