Low temperature synthesis and NOx sensing Al-doped ZnO

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1、SensorsandActuatorsB126(2007)382386LowtemperaturesynthesisandNOxsensingpropertiesofnanostructuredAl-dopedZnOS.C.Navalea,b,V.Ravia,I.S.Mullaa,∗,S.W.Gosavib,∗,S.K.KulkarnibaPhysicalandMaterialsChemistryDivision,NationalChemicalLaboratory,Pune411008,IndiabDST

2、UnitonNanoscience,DepartmentofPhysics,UniversityofPune,Pune411007,IndiaReceived7November2006;receivedinrevisedform16March2007;accepted19March2007Availableonline23March2007AbstractAlthoughZnOisstudiedintensivelyasasensingmaterial,therearelimitedreportsavail

3、ableonaluminum-dopedZnO(AZO)asaNOxsensor.ThispaperreportsselectiveNOsensingcharacteristicsofAl-dopedZnOsynthesizedintheformofporouspelletssinteredat350◦C.ThesalientxfeatureofourexperimentalresultsisthatoursensorcandetectsmallconcentrationsofNOxatloweropera

4、tingtemperature.ItisalsoobservedthatascomparedtogasessuchasSOx,HCl,LPG,H2S,H2,ammonia,alcoholandacetoneitselectivelydetectsNOxduetoAl-doping.TheamountofAlinZnOduringsynthesisisvariedbetween1and10wt%.OursensorsensesNOconcentrationaslowas20ppmat100◦Cwitha%re

5、sponseofx11anda%responseof740at300◦Cfor1wt%Al.OfallthecompositionswithAl-doping,1wt%isfoundtogivebestresults.Sensingexperimentscarriedoutat350◦C,however,donotshowanysignificantimprovementinthegassensingproperties.Thephasecontentsandlatticeparametersweredete

6、rminedbyXRDandtheaverageparticlesizewasobtainedusingScherrerformula.AprobablemechanismforsensingNOxinvolvingoxygenionadsorptionanddesorptiononthesurfaceofsensorhasbeensuggested.©2007ElsevierB.V.Allrightsreserved.Keywords:ZnO;Aluminumdoping;NOx;Sensor;Nanom

7、aterial1.Introductioninfluenceofoxygenpartialpressureontheconductivity.Theporosityandthegrainsizeofpolycrystallinezincoxidemate-Zincoxide(ZnO)isann-typedirectbandsemiconductorrialalsohavenoticeableeffectonthegassensitivitypropertyofawidebandgap(3.4eV).Itisa

8、nimportantmultifunc-[11].tionalmaterialwithwiderangingapplicationsinvaristors[1],Oxygenvacanciesonmetal-oxidesurfacesareelectricallysurfaceacousticwave(SAW)devices[2],transparentcon-andchemicallyactive.Thesev