基于半导体性单壁碳纳米管_富勒烯异质结的高性能透明全碳光电探测器.pdf

文章编号2097-1842（2023）05-1243-14High-performance transparent all-carbon photodetectors basedon the semiconducting single-walled carbonnanotube/fullerene heterojunctionsZHANGLuo-xi，YINHuan，CHENYue，ZHUMing-kui，SUYan-jie*（Key Laboratory of Film and Microfabrication(Ministry of Education),School of Electronics,Information andElectrical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China）*Corresponding author，E-mail:Abstract:Takingadvantageofthehighabsorptioncoefficient,excellentphotoelectricproperties,andhighcarriermobilityofSingle-WalledCarbonNanoTubes(SWCNTs),high-performance,transparent,all-carbonField-EffectTransistor(FET)photodetectorhasbeenconstructedwithahightransmittancemorethan80%inthevisiblelightband,inwhichsemiconductingSWCNT(sc-SWCNT)/fullerene(C60)heterojunctionsasthechannelmaterials,patternedmetallicSWCNTfilmassource/drainelectrodes,grapheneoxide(GO)asthedielectriclayer,andIndiumTinOxide(ITO)asatransparentgateelectrode.Theelectricaltestresultsshowthatthephotodetectorexhibitsastronggate-tunablecharacteristics,andachievesabroadbandspectralre-sponsefrom405to1064nminthevisible-nearinfraredspectralregion.Under940nmilluminationwithalightdensityof5mW/cm2,themaximumphotoelectricresponsivityof18.55A/Wandaspecificdetectivityof5.351011Jonescanbeachieved.Key words:single-walledcarbonnanotubes;Fullerene;all-carbonheterojunctions;hightransparency;field-effecttransistorphotodetector基于半导体性单壁碳纳米管/富勒烯异质结的高性能透明全碳光电探测器张罗茜，尹欢，陈越，朱明奎，苏言杰*（上海交通大学电子信息与电气工程学院薄膜与微细技术教育部重点实验室,上海 200240）摘要：利用半导体性单壁碳纳米管（SWCNT）的高吸收系数、优异的光电特性和高载流子迁移率等特点，本文构筑了基于半导体 SWCNT（sc-SWCNT）/富勒烯（C60）异质结的透明全碳宽光谱的场效应晶体管光电探测器。该器件的大部分结构均由碳基材料组成，全碳异质结作为导电沟道材料，金属性 SWCNT 作为源漏电极，氧化石墨烯（GO）作为介质层，在可见光波段的透光率均高于 80%。电学测试结果表明：该光电探测器表现出了较强的栅控能力，实现了从 405收稿日期：2022-11-24；修订日期：2022-12-12基金项目：国家自然科学基金（No.61974089）SupportedbytheNationalNaturalScienceFoundationofChina(No.61974089)第16卷第5期中国光学（中英文）Vol.16No.52023 年 9 月ChineseOpticsSept.20231064nm 的可见光-近红外宽光谱响应，在 5mW/cm2的 940nm 激光照射下，该器件光电响应率可以达到 18.55A/W，比探测率达到 5.351011Jones，同时，表现出了优异的循环稳定性。关 键 词：单壁碳纳米管；富勒烯；全碳异质结；高透明度；场效应晶体管光电探测器中图分类号：TN15文献标志码：Adoi：10.37188/CO.2022-02431IntroductionDuetotherapiddevelopmentofsemiconduct-ortechnologyandinformationscience,theresearchonphotosensitivedeviceshasreceivedextensiveat-tention.Photosensitivedevicesplayacrucialcoreroleinmodernopticaldetection,opticalcommunic-ation,optical information processing,and opticalcontroltechnologies in industrial technology,na-tionaldefense,military,andcivilianfields.Asthescale and diversity of applications are increasing,thedemandforlightdetectiondeviceswithhigherspeed,high conversion efficiency or wide wave-lengthrange,flexibility,andtransparencyisbecom-ingmoreprominent.Moreover,thereareincreasingrequirements for the operational performance ofphotodetectors,suchashighsensitivityandrespons-ivityaswellasfastresponsespeed,lownoiseandlowpowerconsumptionofthedevicesintheoperat-ing wavelength band1.Kobe University2 has de-veloped an infrared sensor with high responsivityat RT,and the central part of the device is anAl0.3Ga0.7As/GaAs heterostructure.The maximumphotoelectricresponsivityof0.8A/Wandaspecif-icdetectivityof1.81010Jonesareachievedatabout6.6matabiasof1V.Althoughconventionalsilic-on-basedphotodetectorshavetheadvantagesofma-turepreparationprocessandlowcost,thewidebandgapofsiliconmaterials(1.12eV)limitstherangein working wavelength3.In addition,the energyband structure of the indirect band gap of siliconmaterial makes it impossible to achieve high-effi-ciency photoelectric conversion,especially in thefieldoftransparentoptoelectronics.Inthisfield,thelightabsorptioncapacityofmaterialssuchassilic-on,germanium,indium gallium arsenic and othermaterialswith high transparency is drastically re-duced,makingitdifficulttoachievetheperfectin-tegrationof high transparency and high optoelec-tronic performance.At present,most photoactivematerialsusedinphotodetectorsareinorganic,andthemanufacturing process of these materials re-quireshightemperatureandhighenergyconsump-tion,and the growth process needs to use manycomplex methods.These methods are complex,sensitivetoprocessfluctuations,andhavehightech-nical requirements.In addition,the processes andphotoactive materials themselves typically containharmfulelementssuchaslead,mercury,cadmiumand arsenic.Therefore,the development of NIRphotodetectorsbasedonnewmaterialshasgradu-allybecomearesearchfocusinrecentyears.Sincethe1960s,theemergingfieldoforganicelectronicshasmadetremendousprogressincatch-ingupwithinorganicsemiconductortechnologyandnowoffersalternativesformanyoptoelectronicap-plications.Thedevelopmentofinorganicmaterialsiscurrentlydominatedbyinorganicsemiconductorsormetals,suchastransparentelectrodes,thin-filmtransistors,solarcells,andphotodetectors.Amongthem,low-dimensionalnanoscalematerialshaveat-tractedmuch attention for their potential applica-tionsinnewprintable,highlyintegratedflexibleandself-powered photochemical UV-NIR broad-spec-trumphotodetectors.Inrecentyears,allotropestructuresofcarbonsuch as fullerenes(C60),carbon nanotubes,andgraphenehaveattractedagreatdealofresearchin-terestandexperimentalapplicationsduetotheirsu-periorchemical,physical,mechanical,andelectron-icproperties.Dependingonthechemicalproperties,some of these carbon materials are metallic andsome are semiconducting and can form insulatingoxides.Therefore,theuseofthesematerialsincom-bination to fabricate new optoelectronic devices1244中国光学（中英文）第16卷composedentirelyofcarbon-basedmaterialsofferssomeattractivepossibilitiesforthedevelopmentofnext-generation electronic devices.Carbon-basedmaterialsareveryabundantonEarth3-4andcanbedispersedanddepositedusingsolutionprocesses,sothey can be used directly in well-developed toolsandprocesses5,andtheseadvantageslaythefound-ationforthedevelopmentofcarbonnanomaterialsforresearchandapplications.Duetotheirexcellentelectricalconductivity,hightransparencyandhighrobustness,carbonnanomaterialshavereceivedhighattention,especially Single-Walled Carbon NanoTubes(SWCNTs).As a typical quasi one-dimen-sionalnanomaterial,SWCNTshavespecialelectric-alandopticalproperties6-7andhavebeenextens-ivelyinvestigatedinvariousapplicationfields,suchastransistorsandsolarcells8-9.Accordingtotheirdiametersandchirality,SWCNTsexhibitsemicon-ductingormetalliccharacteristics10.Thebandgapsof semiconducting SWCNTs(sc-SWCNTs)withdifferentdiametersvaryfrom0.5to1.2eV.Duetotheirultra-highcarriermobility(105cm2/Vs),highabsorptioncoefficients(104105/cm),andlongex-citondiffusionlength,sc-SWCNTsarecommonlyusedasactivematerialsforhigh-performancecar-bon-basedphotodetectors11-12.Inaddition,theelec-trontransitionofsc-SWCNTsissensitivetopolar-izedlightduetotheirspecificangularmomentuminitssubbandgap,thusfurtherexpandingthedetec-tionapplicationsofsc-SWCNTs-basedphotodetect-ors13-14.Duetotheaboveuniqueproperties,sc-SW-CNTshavebecomeanidealmaterialforlighten-ergycollectioninbroadbandlightdetection.Therehavebeennumerousreportsonthere-search and applications of various photosensitivedevices based on sc-SWCNTs.Researchers fromPekingUniversity15havedevelopedanasymmetricstructurebased SWCNT photovoltaic type IR de-tectorwitharesponsivityof9.87105A/Wandadetectivityof107Jones.ThistypeofIRdetectorhastheadvantagesofsimpleprocessandnocoolingIRdetection at RT.L Pengs team16 also reported ahigh-performancephotodiodebasedoncarbonnan-otubestreatedbyadopant-freetechniquesolution,whichcanoperateatRTandzerobias.Thebroad-band response range of the detector is 785 2100 nm,and the detectivity exceeds 1011 Jones.However,thephotogeneratedelectron/holepairsinsc-SWCNTsusuallyremainintheexcitonstate,andtheseparationofexcitonsusuallyrequiresastrongelectricfieldoraninternalelectricfieldtogeneratephotocurrentsintheexternalcircuit.Therefore,thedissociationandtransferofexcitonsneedtobeen-hancedbycombiningwithothermaterialssuchasbulksemiconductors,nanomaterials,andpolymersto form heterojunctions17-19.Due to its sphericalstructure,C60 hasa high electron affinity and re-quires less recombination energy during electrontransfer.Therefore,C60tendstoaccelerateforwardelectron transfer and slow down reverse electrontransfer,resulting in long-lived charge-separatedstates20-22.In various optoelectronic applications,C60iscommonlyusedasanefficienttrappingmater-ial for photogenerated electrons,which generateshigher photocurrents by trapping light-generatedcarriers and enabling longer carrier recombinationlifetimes23-24.Inaddition,theall-carbonheterojunc-tionconstructedfromsc-SWCNTsandC60canalsoavoidinterfacialatomiclayerdiffusiontoacertainextent,whichismorefavorableforthedissociationof photogenerated electron-hole pairs18.A novelphotodetector based on graphene nanoribbons-C60heterostructuresispreparedbyProf.WangsgroupatNanyangTechnologicalUniversity,Singapore.Itcan achieve a high photoresponsivity of 0.4A/Wundermid-infraredlaserirradiationatroomtemper-ature,whichenhancedthephotoresponsivityofthetransistorbyaboutanorderofmagnitudeoverthatof pure graphene21.This high performance isachievedbythehighelectroncaptureefficiencyoftheC60filmdepositedonthegraphenenanoribbon.Suchcarbonmaterialheterojunctionphotodetectorspave the way for the realization of flexible andbroadband photodetectors for various applications第5期ZHANGLuo-xi,et al.:High-performancetransparentall-carbonphotodetectors.1245suchasimaging,remotesensing,andinfraredcam-erasensors.Ontheotherhand,field-effecttransist-ors usually use gold as the electrode material,however,theuseofgoldwilldecreaseopticaltrans-parency,whiletheuseofmetal-freedevicessuchasSWCNTcannotonlyachieveopticaltransparencyandmechanical robustness,carbon-based conduct-ivematerialalsohaveadvantagesoverothermetalcontactsinelectricalcontactcarbonnanostructures.Therefore,thispaperconstructsatransparent,all-carbon field-effect transistor-type photodetectorbasedonsc-SWCNT/C60heterojunctions,metallicSWCNTsassource-drainelectrodes,grapheneox-ide(GO)asthedielectriclayer,andindiumtinox-ide(ITO)asthetransparentgate.Thehightransmit-tanceofthedevicewasdemonstratedbycharacter-izingthelighttransmissionofthesamplebyUV-Vis-NIR spectrophotometer.The modified sc-SW-CNTmaterialischaracterizedandanalyzedbyscan-ningelectronmicroscopyandRamanspectroscopyfor microscopic morphology and charge transferlevel,andtheresultsshowthatC60playedap-typedoping role for sc-SWCNT.The electrical testsdemonstrate that the device has a more sensitivephotoelectricresponsetovisible-near-infraredlightinthe4051064nmband,expandingtheapplica-tionofthephotodetectorinnext-generationtrans-parenttechnologiessuchassmartwindowsandarti-ficialintelligenceglasses.2Experiment2.1Preparationofsc-SWCNT/C60all-carbonde-vicesFirst,the(6,5)SWCNT dispersion was pre-pared.0.5mgof(6,5)SWCNTpowder(Sigma-Ald-rich)was weighed and dispersed into 10mL ofaqueous sodium dodecyl sulfate(SDS)solution(0.01g/mL).After2hofultrasonictreatmentinanicebath,theinadequatelydispersed(6,5)SWCNTpowderwasremovedbycentrifugationat14000rpmfor30min,andthesupernatantaftercentrifugationwasdiluted5timestoobtainahomogeneous(6,5)SWCNTdispersion.Then,GOfilmswerepreparedby vacuum extraction and filtration method andusedasthedielectriclayerofthetransistors.AfterdilutingtheGOaqueoussolutionandsonicatingatlow temperature for 1h,10mL of the dispersionwasgraduallyaddedtoavacuumfiltrationdevicecontaining a 0.22m cellulose membrane andfilteredtoformahomogeneousGOfilm.Afterfil-teringtheaqueoussolution,excessdeionizedwaterwas added to clean the excess SDS in the film3timestoreduceitseffectonthefilmperformance.Finally,theGOfilmsonthecellulosemembranesweredriedinavacuumovenat40Cfor2h.TheaqueousgrapheneoxidesolutionwasreplacedwithahomogeneousdispersionofmetallicSWCNTindeionized water(0.05mg/mL).Vacuum filtrationwasperformedinthesamewayasdescribedabovetoobtainuniformanddenseconductivesc-SWCNTfilmsasabackupmaterialforthesource-drainelec-trode.ITO conductive glass with a thickness of135nmwasusedasthesubstrateandthegateelec-trode.First,theITOconductiveglasswascleanedwithdeionizedwater,acetone,isopropanolandeth-anolinordertoremoveoilfromthesubstratesur-face.Then,theGOfilmonthepreparedcellulosefilmwastransferredtotheITOsubstrate,andtheGOfilmwaslaminatedandspreadontheconduct-iveglasssurfaceusingethanolandwater,andthenthecellulosefilmwasdissolvedinacetonebysoak-inginacetone,andwashedrepeatedlywithacetonetoprevent the residual cellulose film on the sub-stratefromaffectingthedeviceperformance.Then,theabovepreparedsc-SWCNTdispersionwasde-positedontheGOsurfacebyspincoatingmethodat2000rpmtoformauniformfilm,and2mgofC60wasweighedbyvacuumthermalevaporationmeth-odtomakeuniformvaporizationontothesurfaceofthecarbontubefilm.Theheterojunctionof(6,5)SWCNT/C60onthesubstratewasconstructedbyan-nealingat60Cfor1hundervacuum.Finally,the1246中国光学（中英文）第16卷metallicSWCNTfilmobtainedbysuctionfiltrationwas transferred to the sc-SWCNT/C60 heterojunc-tionbyrepeatingtheabovestepstoformasource-drain pattern.The channel width between thesource-drainelectrodesis200mandthelengthis400m.2.2TestingandcharacterizationIn this paper,the surface morphology of sc-SWCNTfilms/C60heterojunctionsaswellasmetal-lic SWCNT was characterized using a scanningelectronmicroscope(SEM,ZeissUltraPlus,Ger-many).Thetransmissionspectrawereobtainedbycharacterizing the transmittance of the samples tolightusingaLambda950modelUV-Vis-NIRspec-trophotometer(USA).TheRamanpeakshiftsoftheheterojunctionwere analyzed by Raman spectro-scopy statistics at an excitation wavelength of514nm.Theoptoelectronicpropertiesofthedeviceswereevaluatedatroomtemperatureusingasemi-conductor parameter analyzer,and the current-voltage(I-V)curvesandcurrent-time(I-T)curvesofthedevicesweremeasuredundertheirradiationofvarious monochromatic laser diodes with ad-justable power as the signal source of the opticalpulses(laserwavelengthsincluding405,532,650,780,860,940and1064nm).3ResultsanddiscussionThestructurediagramoftheconstructedfield-effecttransistorisshowninFigure1(a),whereITOandGOformthegateanddielectriclayer,sc-SW-CNT/C60 heterojunction serves as the conductivechannel,and metallic SWCNT forms the source-drainelectrode.Figure1(b)showstheopticaltrans-missionspectrumwithinthevisiblelightrangeofthechannel(sc-SWCNT/C60film)region.Theinsetshowsthephysicalimageofthepreparedfield-ef-fecttransistordevice.Itisobviousthatalmostallcarbonmaterial films deposited on ITO are com-pletelytransparent,andtheirtransmittanceisonly10%lowerthanthatofthesubstrate.When80%ofthesubstrateiscoveredwithsc-SWCNTfilm(form-ingchannels and electrodes),the optical transmit-tanceofthedeviceremainsabove80%,indicatingthatthedesignofthedevicedoesnotaffectthelightabsorption of the channel layer itself.Figure 2(a)shows the carbon nanotubes deposited on GO byspincoating,sc-SWCNTisevenlydistributedthrou-ghouttheentireregion,andnoobvioussurfacedis-persantsorotherpolymersarevisibleintheimage,demonstratingthe high dispersibility of the nan-otubes.Thecarbontubesolutiondispersedandcent-rifuged by ultrasound ensures the uniformity anddensityofthesc-SWCNTsfilm.Figure2(b)showsthe SEM image of the sc-SWCNT/C60 compositefilm,from which it can be