文献翻译——传感器与执行器B化学

第1页外文文献资料SensorsandActuatorsB:Chemical1.IntroductionThestabilityissueisnotoftendiscussedinliteraturedevotedtoconductometricgassensors,whencomparedtoeithersensitivityorselectivityissues.However,stabilityisakeyqualityindicatorinthedevelopmentofgassensorsforrealmarkets.Ashasbeenknown,devicesdesignedforthesensormarketshouldexhibitastableandreproduciblesignalforaperiodofatleast23years(typically1700026000hofoperation).Possibly,thislackofdatainliteratureisrelatedtothefactthatthesensorlaboratoryinvesti-gationsarefrequentlylimitedintimescale,andduetothefactthatcompaniesproducingsensorsdonotpublishalltheirdatainopenscienticjournals.Butstill,thetemporaldriftofoperatingchar-acteristicsofconductometricgassensorsbasedonmetaloxides(MOX),alongwiththelowselectivityofsensorresponses,arecon-sideredtobemajordisadvantagesofthesedevices15.Itwasfoundthatsensoragingandenvironmentaldisturbancesproducechangesinsensorresponsesthatmakeinitialstatisticalmodelsforgasorodorrecognitionrelativelyuselessafterarelativelyshortperiodoftime.Besides,suchdriftsubstantiallylimitstheabilitytomeasuretheabsolutevalueoftargetgasconcentrationsandrequiresperiodicsensorcalibration4,5.Forexample,inanalarmsystemsetforaspeciedlevelofapoisonouscontaminant,thedrifttermsmayleadtoafalsealarmorafailuretoannounceadangerouscontaminationlevel.Takingintoaccounttheimportanceofthelong-termstabilityofchemicalsensorsignalsfortheirpracticaluseinvariousappli-cations68,weattemptheretosummarizemodernviewspertainingtothereasonsfortimeinstabilityingassensorparame-ters,inadditiontoapproachesthatcouldbeusedtoimprovetheirstability.However,itshouldbenotedthatwearenotgoingtoana-lyzethekineticsofthedriftortheimpactofprocessesinvarioustypesofdrift.Notealsothattherearebothlong-termandshort-termdriftcomponents.Long-termdriftcanbeobservedduringallexploitationperiods,whereasshort-termdrift,whichisasarulemoreintense,usuallybecomesapparentduringtherstdaysofexploitation(upto10days)7,911.Todate,therehasbeenalackofnecessaryinformationforadetailedanalysis;thus,thepresentreviewshouldjustbeconsideredasabriefintroductiontotheproblemofinstabilityandasashortguidetoactionfordesignersinvolvedinthisnewareaofsemiconductorgassensors.Beforewebeginthisreview,however,itisrstnecessarytostatethatsomeoftheprocessesresponsibleforthetemporalinstabilityofgassensorparameters,suchaspoisoning,sinter-ing,cokingorfouling,attrition,materialvolatilizationanderosion,thermalshocks,andphasetransformation,havealreadybeencon-sideredduringdifferentanalysesofheterogeneous(combustion)catalystdeactivation12.Indeed,thehighgasvelocity,pressure,andtemperature(upto1000C),aswellasthelargevariationsintemperature,putharshdemandsonthecatalystmaterial;moredetailsofcombustioncatalystdeactivationaregiveninseveralear-lierpublishedreviews1316.Ofcourse,duetothelowerworkingtemperaturesandotherconditionsandfundamentalsofoperation,mentionedaboveprocessesingassensorshavedifferentintensi-tiesandinuencesontheoperatingcharacteristics,althoughthereareadditionalfactorsingassensorsthatinuencetheirstabilityandreliability.Nevertheless,webelievethattheinformationpre-sentedinthesearticleswillbeusefulforabetterunderstandingofthenatureofprocessestakingplaceinsolid-stategassensors,espe-ciallyasreviewpapersrelatedtoanalysisofgassensorinstabilityarenotablyabsent.FactorscontrollingthetemporalinstabilityofsensorparametersAnanalysisofcurrentliteratureallowedustocon-cludethatinstabilityintheperformanceofthe第2页MOXconductometricsensorisconditionedbyanumberofreasonslistedbelow.2.1.StructuraltransformationStructuraltransformationsarerstconditionedbythegrowthofgrains,duetotheircoalescence6,17.Forexample,Nakamura18establishedthatthegrainsizeinpolycrystallinestructuresfab-ricatedbySnO2powdersinteringchangedduringthreeyearsofoperation,from515nmto2040nm.MatsuuraandTakahata19thenobservedagrowthingrainsize,evenafter20daysofexploita-tion.Andbyreviewingtheresultspresentedin2024,itcanbenotedthatsuchachangeingrainsizecouldexertastronginuenceonsensorparameters.Indeed,atpresent,grainsizeisconsideredasoneofthemostimportantparametersofgas-sensingmaterials,essentiallycontrollingalloperatingcharacteristicsofsolid-stategassensors20,21,2426.AccordingtoKorotcenkovetal.20,26,thechangeofgrainsizecouldbeaccompaniedbythefollowingeffects:a)Changeofthegeometricsizeofthegrainsnetworkwithinapoly-crystallineMOXlayer,i.e.,theareaofinter-graincontact,poressize,etc.21,27.Themasstransferfromsmallergrainstolargeronesstimulatesbothanincreaseinthecontactareabetweencrystallitesandtheappearanceofnecksbetweengrains.Previ-ously,itwasshownthatinmanycasesjusttheseparameterscouldbeusedtocontroltheconductanceandgas-sensingprop-ertiesof3Dor2Dgrainnetworkscomprisingthepolycrystallinelayers24,28.Itwasalsoestablishedthatthereareseveraldif-ferentpathsfortransportingmaterialsintheinitialstageofthesinteringprocess12;materialscanbetransportedtotheneckregionviavaportransport,surfacediffusion,diffusionalongthegrainboundaries,ordiffusionthroughthecrystallattice.Finally,mattercanbetransportedfromdislocationsinthelatticetotheneckvialatticediffusion.Inaddition,ithasbeenshownthatsur-facediffusionoccursmostlyduringtheearlystagesofsintering,andthatvolumediffusionbecomesincreasinglyimportantinthelaterstagesofthegrainboundarysintering12.Thiscorre-lationbetweengrainsizeandlmporositycanbefoundin29;thestructuralpropertiesofSnO2lmssynthesizedusingsolgeltechnologywereanalyzedanditwasfoundthattheporesizeincreasedduringsintering,accompaniedbyagrowthingrainsize.b)ChangeoftheelectrophysicalpropertiesoftheMOXlayers.Researchhasshownthatthegrowthofgrains,especiallyinthenmrange,mightbeaccompaniedbyachangeofthebandgapandconcentrationofpointdefectsofMOX30.Itisalsoknownthatwhenthegrainsizedecreasesbelowacertaincrit-icalvalue,comparabletodimensionsofthesurfaceorgrainboundaryspacechargeregions,mostofthephysicalandchemi-calparametersarepartiallyorentirelysensitivetopropertiesofthesurfacelayer31.Thus,theimportanceoftheelectrophys-icalparametersingas-sensingmaterialsrequiredforoptimaloperatingcharacteristicsisnotasubjectofdoubt8,24.c)ChangeoftheelectronandcatalyticpropertiesoftheMOXsur-face.In22itwasestablishedthatthechangeingrainsizeisusuallyaccompaniedbychangesingraincrystallographiceterinSnO2lmspreparedbyspraypyrolysisareshapedlikespherulites,andcontainalargenumberofsteps,whereasgrains1020nmindiametertendtofollowmacrocrystalfaceting27.Assuch,itwasestablishedthatcrystalliteslessthan80nminsizehavedominantplanesof(111),(111),(200),(020),(112),(120),and(210),whereasthemajorplanesincrys-tallitesexceeding80100nmare(101),(101),(110),(101),(011),(011),(011)and(011).Therefore,takingintoaccountthateachcrystallographicplaneexhibitsaspeciccombina-tionofelectronicparameters,itcanbeconcludedthattheabove-mentionedtransformationissignicantforgassensorperformance,because:(i)thechangeincrystalfacetingresultsinachangeintheadsorptionandcatalyticpropertiesofthesample,and(ii)thechangeincrystalfacetingchangestheprop-ertiesofinter-graincontacts,controllingtheconductivityofthegas-sensinglayer.Itwasalsoestablishedthatthetemperature,atmosphere,metaloxidetype,catalystdispersion,presenceofpromotersorinhibitors,supportsurfacearea,andthetextureandporosityofthesens-inglayerareprincipalparametersaffectingtherateofstructuraltransformations15,21,27,3234.Moreover,itwasfoundthattherateoftheseprocesses第3页increasesexponentiallywithtemperature23,3234.Thechangeoflmmorphologymayalsobecausedbymigrationand/orsegregationofadditives35,36,althoughvariationofthegrainnetworksduetoamismatchofthethermalexpansioncoef-cientcanalsoincurchangesinthesensorcharacteristics35,37.AccordingtoSharmaetal.38,crackingisthemainreasonfordriftinsensorparametersmicrofabricatedonmicro-hotplateplatforms.Whenthesensinglayerandsubstrate,whichusuallyhavedifferentthermalexpansioncoefcients,aresubjectedtothermalcycling,theresultisstressinthecoatingtherebyleadingtocracks12.Researchhasalsoshownthatirreversiblestructuralchangescon-nectedwiththeabovefactorsoccur,withespeciallystrongeffectsinthickerlms36,37.Duringtheheatingandcoolingcycles,thewallsofthemonolithcoolorwarmfasterthanthebulkandthisinducesathermalgradientwithintheceramic,leadingtofrac-tures;badadhesionofthesensinglayerfurtherpromotessuchmodications.Subsequently,asthepost-depositionannealingtimeincreases,thenumberofcracksinthemetaloxidelmincreasesaswell,althoughinthinlms,thiseffectisseldomobserved36.Structuralchangesinmetaloxidelmscanalsobecausedbythenon-uniformsurfacedistributionofcurrentdensityandthecor-respondingnon-uniformheatingofmetaloxidelms36.Andinterfacialreactionsatthemetalelectrode/ceramicinterfacemaycontributetotheinstabilityofgassensorparametersaswell17.2.2.PhasetransformationUnderthelong-termoperationofgassensorsbasedonMOXdopedwithadditives,theseadditivescouldsegregateintosepa-ratephases27,39.Here,therateofsegregationiscontrolledbylatticediffusion,andthereforethesegregationequilibriummayberapidlyestablishedatelevatedtemperatures;atlowertempera-tures,thisprocessmaybeconsiderablyslower.Researchhasalsoestablishedthattheextentofsegregationstronglydependsonthecompositionofboththebulkphaseandthesurroundinggasphase,whichcontrolthedefectconcentrationinboththebulkandwithinthenear-surface(grainboundary)region31.Itwasfoundthatthelimitedsolubilityofadditivesinmetaloxidesalsodependsonthegrainsizeandcrystallinity;solubilityofadditivesinmetaloxidesusuallydrasticallydecreaseswithincreasinggrainsize40.Thisndingindicatesthatannealing,subsequentlyfollowedbygraingrowth,promotestheprocessofimpuritysegregationonthesur-faceofthosegrains.Thus,theeffectofsegregationinmetaloxidescanleadtoessen-tialchangesinthechemicalandelectrophysicalpropertiesofthenear-surface(grainboundary)layerwithrespecttothecrystallinebulk41.Thismeansthatsegregationprocessesmayplayacon-siderableroleintheformationofthesurfacelayerandaffectconditionsofcurrentowthroughpolycrystallinematerials,whichcontroltheconductivityandsensorsensitivity;interfacesinsuchtwo-phasesystemswillbecontrolledbythepresenceofthesecondphase39.Possiblestructuraltransformationsofgas-sensinglms,pertainingtotheappearanceofthesecondphase,werepreviouslyshownin42,43.Andamoredetaileddescriptionoftheprocessesrelatedtograinboundarysegregationinoxideceramicscanbefoundin31,41,4446.Thephasecompositionmightalsobechangedduetochemi-calreactionsbetweenthesubstrateandreactivecomponentsfromthesurroundingatmosphere.Forexample,thereactionwithCl2isaccompaniedbygenerationofvolatilechlorides.Moreover,theproductsofthesereactionsmayadditionallydopesensingmateri-alsand/orgenerateeitherisolatingorgas-insensitivelayersnexttothesubstrate.Theinteractionbetweenthegas-sensinglayerandsubstratecanalsobethesourceofanewphase.Forexample,thereactionofGa2O3withAl2O3atatemperatureof1000CmaybeaccompaniedbytheappearanceofanAIxGa2xO3(x1200C)theplatinumunderoxidationcancreatevolatileoxides62thatdestroysensormetallizationlay-ers(electrodesandheaters).Anotherpotentialreasonforpossibleparameterchangesincontactsandheatersisthebadadhesionofplatinum,andthatusingasublayer第5页(Ti)doesnotresolveallprob-lems.Forexample,Eschetal.60,whileanalyzingthebehaviorofTiPtlayersdestinedforformingtheheaterelementsofchemicalsensors,establishedthatduringexploitationthePtsurfacelostitsmetallicluster,andatatemperatureof650C,hillocksappearedontheheatersurface.Inotherwords,thisthermaltreatmentinducedthediffusionandoxidationofTi,especiallyforannealingtimesofupto2hat450C.Longerheattreatmentsdidnotfurtheraffectthechemicalcomposition,andannealingat650Cgaverisetohillockformationandstrongadhesionproblems.2.5.BulkdiffusionConductometricgassensorsoperateinconditionsinwhichthebulkpropertiesofmetaloxidesarenotinequilibriumwiththesurroundinggas.Thesurroundinggasaffectstheelectricalproper-tiesofmetaloxidesthroughsurfacereactionswithoutinuencingtheirbulkproperties.However,despitetheirratherlowdiffusioncoefcients,thediffusionofoxygenvacancies,otherpointdefects,andthedifferentionsthroughouttheoxidebulkarepresentevenatoperatingtemperaturesof200500C63.Takingintoaccountthattheseprocessesareaccompaniedbymodicationoftheelec-trophysicalandsurfacepropertiesofmetaloxides,itbecomesclearthationicdriftcouldalsobeanadditionalsourceofthetemporaldriftofgassensorparameters64,65.2.6.ErrorsindesignErrorsindesigningandinchoosingintermediatematerials,usedformanufacturing,arealsoanimportantfactorcontributingtotheobservedinstabilityinsensorparameters.Asisgenerallyknown,nosensorcanbedesignedwithoutconsideringthenalpackage,andinteractionofsurroundinggaswithanunstablesensorcasinghasoftenbeenthemainreasonfordegradingsensorparameters.2.7.ChangeofhumidityMOXsensorsareregularlyrequiredtoworkinanatmospherecontainingwatervapor,althoughmanyMOXsensorsarerathersensitivetothepresenceofhumidityintheatmosphere66,67.Itwasestablishedthattheadsorptionofwaterisadominantfac-torintheformationofsurfacecharacteristics,bothwithrespecttotheadsorptionofotherspeciesandinsurfacecatalysis68.Theadsorptionofwateralsoaffectstheelectronicpropertiesofsemiconductingmetaloxides,whichtypicallyactasadonor.Thus,watervapormaysubstantiallymodifythesensorresponse58,69,especiallyiftakingintoaccountthattherelativehumidityofthesurroundingatmospherecouldvaryfrom10%to100%.There-fore,itisnotsurprisingthatchangesintheambienthumidityinducesignicantlong-termvariationsinboththeconductanceandcalibrationcharacteristicsofMOXgassensors7073.Asanotherfactor,therehasbeenanassumptionthathydroxylationofthesurfaceisresponsibleforthesensorperformancemodi-cationincurredduringsensorstorage1;longexposurescanleadtohydrationofthesurfacelayer,andcorrespondinglytoadriftofchemicalsensorcharacteristics73,74.Forexample,hydroxylationoftheSnO2surfacewasfoundtoinhibitsorp-tionforallthegasmixtures(CH4,CO,CO2,O2)examinedin68.2.8.FluctuationsoftemperatureinthesurroundingatmosphereTheuctuationoftemperatureinthesurroundingatmospherecanalsoinduceadriftinsensorparameters72.Ataconstantmicro-heaterpower,variationoftheambienttemperaturecausesuctuationsintheoperatingtemperature,whichcanbeaccompa-niedbychangesofboththeconcentrationofthechargecarrierswithinthegrainsoftheoxidesemiconductorandpropertiesoftheinter-graincontacts.Kineticsofthegassurfaceinteractionsarealsostronglytemperaturedependent75,76;therefore,asmalltemperaturechangehasthepotentialtocauseaconsiderablevari-ationinsensitivityandresponsetime.第6页2.9.InterferenceeffectsMetaloxidegassensorsarenotselective27,58.Therefore,theappearanceofuncontrolledgasesandseasonalcyclingintheatmo-spherecompositionmayalsoleadtochanges,whichinsomecasescanbeconsideredasadriftinsensorparameters.第7页中文翻译稿传感器与执行器B:化学1.介绍众所周知，被设计用于传感器市场的那些设备，应该展示出在至少在一段时间内2-3年(通常是17000-26000小时内操作)足够的稳定性和可移接性。有可能的，这个在文献中缺少的数据与传感器实验室调查频率被时间规律所限制的事实有关1。根据这个分析原因，一些公司生产的传感器不会再科学杂志上公布所有的数据。事实表明，传感器的年限和环境干扰产生改变了传感器的相应，致使早期的气体和气味统计模式，指导经过了一个短暂时期后才相互关联。(1000C),以及大的变化在温度,将要求苛刻的催化剂材料、更多详细给出了燃烧催化剂失活在几个耳朵-评论13肝出版。当然,由于lowerworking温度和其他条件和基本的操作,上面所提到的过程中有不同的intensi-气敏传感器关系和工作特性的影响,虽然在那里额外的因素是影响大学生的气体传感器的稳定性和可靠性。不过,我们相信信息预-这篇文章将介绍在被用在一个更好的了解自然的过程发生在固态气体传感器,espe-cially作为评论文章相关分析了气体传感器的不稳定有明显的缺憾。举个例子，在一个被设置成特殊有毒污染物等级的警报器系统里，这漂白的规定有可能导致一个错误的警报或一个错误的污染等级的断论。考虑到他们在各种应用中练习实用的化学类传感器信号的长时间稳定性的原因的模式，此外还有被用于改善他们稳定性的方法。但是值得注意的是，我们并不准备分析漂白的活动性或者通知不同类型漂白的进程。长效型漂白可以在整个开发器件被观察到，然而像一个更强烈的规则，短效性漂白可以在开发期，超过10天以上的时间里，第一天表现得明显。对数据来说，缺少对细小分析的必要信息。因此，这最近的的介绍必须被考虑成一个对稳定性问题的简报和一个参与在半导体气体传感器新兴领域内的对读者们的简短活动指南。在我们开始介绍之前，然而最有必要陈述的是一些气体传感器参数的暂时稳定性有回应的程序。气体的高速转动、压力和便哈巨大的温度（超过1000摄氏度），在刺激因素上施以刺激的命令。更多细小氧化刺激因素的刺激作用被早期的日志公布。当然，由于更低的工作温度和其他条件和基础材料性的操作，在气体传感器中所涉及到的程序，在操作特性上拥有不同的强烈性和影响力。尽管在气体传感器中有其他的要你告诉可以影响他饿稳定性和可靠性。但是我们相信在致谢文章当中所提出的信息将第8页会对取代固体性气体传感器的自然程序有一个更好的理解，尤其是跟气体传感器和稳定性有关的介绍性报纸显得突出。2.控制时间的不稳定性因素的传感器参数现有文献的分析,让我们共同那不稳定分为MOX性能新传感器受有许多原因的上市下面。2.1体制转型首先受到结构转变的增长的谷物,由于他们的聚结6,17。例如,中村18确定,晶粒结构难以置信。多晶硅粉末烧结的三年内的变化操作,from5-15nmto20-40海里。MatsuuraTakahata19然后观察其生长在粒度,甚至在20天的exploita-信息。通过考察结果,提出了,二十指出,这一变化在粒度可以产生强烈的影响在传感器参数。事实上,目前,颗粒大小较考虑作为一种最重要的参数gas-sensing材料,基本上所有的操作特性控制固态气体传感器20、21日。根据Korotcenkov吴昱。20,26,晶粒尺寸的变化可能是伴随着以下效果:变化的几何粒度的网络在聚-水晶MOX层,即,面积inter-grain接触,毛孔尺寸等。2721日。转移fromsmaller异形粮食大增加的刺激都接触面积crystallites形状之间的颈项上颗粒。Previ-结果表明:不断,在很多情况下,只是这些参数可以用来控制导度、gas-sensing支柱-erties2Dgrain网络三与其组成的多晶硅24,28层。它也被确立,有几种见dis-transportingmaterials厂家途径在初始阶段烧结过程,材料12被流放的脖子通过蒸汽运输、表面地区扩散、扩散沿晶界、或扩散通过晶格。最后,物质可以被运输的fromdislocations格子的通过晶格扩散的脖子。此外,它已经表明,见sub-面对扩散的早期期间occursmostly烧结,体积扩散,变得越来越重要的后期,晶界烧结12。这来往lation粒度和filmporosity之间可以找到(29岁);电影的结构特点SnO2使用溶胶-凝胶法合成技术进行了分析,结果发现,孔隙的大小增加了在烧结过程中,伴随着粮食增长大小。变化特性electrophysicalMOX层。研究表明,颗粒的生长,尤其在在海里范围,可能伴随着变化的乐队点缺陷的差距和浓度的30MOX。这也是知道当粒度降低致命一击低于一定标准价值,相当于一个维度的表面或粮食边界空间电荷的地区,大部分的物理化学作用-卡尔参数部分地或全部地敏感的特性表层31。因此,electrophys的重要性gas-sensing古典参数最优所需材料操作特征不是一个主题的文献8。变化的电子与催化性能MOX见sub。在成立22的改变是因为晶粒尺寸通常伴随着粮食结晶变化吗faceting。例如出发,发现颗粒直径5-10nmin-彼得在SnO2电影喷雾热解法是制备形状像spherulites,并包含大量的步骤,而粒followmacrocrystal直径10-20nmin倾向于faceting27。因此,它是建立crystallites小于80奈米飞机在优势第9页的大小(1-1),1(1)、(20,0),(0二0),(2)11,(1),为2比01比0(2),而主要的飞机crystallites超过80-100海里(1比0-1),(1),1比0(1,0),(10-1),1(0-1),(01),(0-1),1(0-1)。因此,考虑到每个晶体平面展具体combina-起跳的电子参数,可以得出了对于上述变换气敏传感器(我的表演,是因为在水晶faceting)改变结果在一个变化的吸附和催化性能样本,(2)改变在水晶faceting支柱变化ertiesinter-grain的接触,控制的导电性gas-sensing层。这也建立了温度、大气、金属氧化物型、催化剂、有无发起人分散或抑制剂,支持表面积和孔隙率、纹理的sens-ing层率的主要参数影响的结构变换(15,21岁,27日,32-34。此外,发现这些过程的速度与温度呈指数增加23,32-34。filmmorphologymay的变化也有可能产生bymigration水和/或分离(混凝土添加剂,3635,尽管变化的影响粮食网络由于热膨胀系数不匹配之ficient也可以招致变化特点35岁的传感器。根据沙玛吴38,主要原因是裂纹漂移在传感器parametersmicrofabricatedonmicro-hotplate平台。当感应层和基体,通常有不同热膨胀系数,受到热循环,结果是导致应力裂纹coating-thereby12。研究也表明,欺诈不可逆的结构性变化-nected与上述因素发生,特强的影响涂层越厚36岁,在37。在加热和冷却周期一枝独秀的墙凉爽还是暖和比体积和这个一级内的温度梯度,从而导致防砂陶瓷-温度;坏的感应层附着力促进这样的修改。随后,当post-deposition退火时间增加,裂缝的数量增加金属氧化物薄膜同时,虽然在薄膜、这个效果很少被观察到36。金属氧化物薄膜结构上的改变也会引起表面电流密度不均匀分布和前-响应的非均匀加热金属氧化物薄膜的36。和在界面反应陶瓷/金属电极界面稳定的贡献以及气体传感器参数17。2.2相变受到长期运行的基于MOX气敏传感器掺入添加剂,这些添加剂可以隔离。在国家环保总局27日率阶段39。这里的速度控制是通过隔离晶格扩散,因此equilibriummay偏析迅速建立了高温;在较低的蛋彩画-温度,该过程可以大大慢。研究也建立了隔离范围的强烈的依赖两个阶段组成的体积和周围的气体