High‐efficiency photovoltaic modules on a chip for millimeter‐scale energy harvesting Eunseong Moon.pdf

该【High‐efficiency photovoltaic modules on a chip for millimeter‐scale energy harvesting Eunseong Moon 】是由【妙玉】上传分享，文档一共【7】页，该文档可以免费在线阅读，需要了解更多关于【High‐efficiency photovoltaic modules on a chip for millimeter‐scale energy harvesting Eunseong Moon 】的内容，可以使用淘豆网的站内搜索功能，选择自己适合的文档，以下文字是截取该文章内的部分文字，如需要获得完整电子版，请下载此文档到您的设备，方便您编辑和打印。Received:20November2018Revised:epted:25February2019DOI:‐efficiencyphotovoltaicmodulesonachipformillimeter‐scaleenergyharvestingEunseongMoon|InheeLee|DavidBlaauw|,UniversityofMichigan,AbstractAnnArbor,MI,USAPhotovoltaicmodulesatthemillimeterscalearedemonstratedinthisworktopower‐‐CorrespondencewirelesslyinterconnectedmillimeterscalesensorsystemsoperatingunderlowfluxEunseongMoon,DepartmentofElectricalconditions,,UniversityofMichigan,AnnArbor,MI,:******@‐,Grant/‐Number:%underlow‐fluxnear‐infraredillumination(850nmat1μW/mm2).Theoutputvoltageofthemoduleisgreaterthan5V,providingavoltageup‐conversionefficiencyofmorethan90%.Wedemonstratedirectphoto-hargingofa16‐μAhpairofthin‐filmlithium‐ionbatteriesunderdimlightconditions,enablingtheperpetualoperationofpracticalmillimeter‐,ofthings,millimeter‐scaleenergyharvesting,monolithicphotovoltaicmodule,bination,photoinducedshunt1|INTRODUCTIONirradiation().High‐efficiencyPVcellscanmeetthepowerrequirementsContinuedscalingofelectronicsystemsandtheproliferationofwire-(>50nW/mm2)ofthesesystemsthroughoptimizationofthespectralofthings(IoT)1-3responseinappropriatespectralwindows:425to650nmforambientnecessitateameansofenergyharvestingtoachieveself‐(PV)‐basedPVcellscanprovideout-forefficientlarge‐scalepowergenerationandfortheiruseinself‐,miniaturiza-(),,powerconver-lightingorinfraredradiationforwirelesspowertransferdiffersionefficiencyvaluesabove20%underwhiteroomlighting10at580dramaticallyfromsolarirradianceintermsofbothspectralcontentlux()andabove30%under850nminfraredLEDillumi--7DarkcurrentandshuntconductivepathsinPVcellsnation5at1μW/mm2wereachievedusingsingle‐‐fluxThemostcriticalissueinensuringperpetualoperationofsystemsambientindoorconditions4-‐areaapplications,;1–7./journal/pip?2019JohnWiley&Sons,‐scalesystemswasdramaticallyreducedutilizingtheammoniumsulfidechemicalbecauseofthesmallPVarea(andhence,lowcost).‐performancematerialssuchasIII‐Vcompoundsemicon-arrayswereconstructedonsemi‐,tomaximizeenergycapacity,thebatteryofthesemi‐insulatingGaAssubstrateprovidesahigh‐resistivitymaterialthemillimeter‐scalesystemsoftenhaveahighopen‐circuitvoltage,tofacilitateseriesconnectionofPVcells,thereisstillapathforshuntwhichisseveraltimeshigherthanthetypicalopencircuitvoltageofleakagecurrentthatcandegradethefillfactor,-achievevoltageup‐conversion,whereswitchingandresistivelossesrentleakage:limitefficiencytoapproximately50%.12Directseries/parallelconnec-(1)semi‐insulatingsubstratealone,(2)p‐GaAsjunctionbarrier16?3tionsofPVcellsprovideanappealingalternativeforvoltageup‐(500nmthick,10cmdoping),and(3)p‐-conversion,workwithover80%powerconversionrier(400nmthick,5×1016cm?3doping).,monolithicPVarrayscharacteristicsforeachapproachusingSynopsysSentaurusTCAD15presentseveralchallengesinminimizinglossesassociatedtodevicetoobtainoptimizedparametersforlayerthickness,p‐typedopingcon-,13centration,(255μm×595μm)connectedinserieswith10‐μmvoltagegeneration(largenumberofseries‐connectedcellsrequiredtrenchesfordeviceisolation,‐celltoachievedesiredvoltage)andlowopticalabsorptionstrength(thickseriesconnectionwasdesignedtoachieveavoltageoutputofapprox-absorberregionsarerequired,makingdeviceisolationproblem-).9,11,munica-,externalsensor(eg,pressure)-alaserpowerconverterbasedonasix‐cellGaAsPVmodulearraywastricalcharacteristicsofthePVmodulesunderdarkandilluminateddemonstratedatthemillimeterscalewithconversionefficiencyconditionsusingKeithley2400and4200semiconductorcharacteriza-greaterthan52%‐lightLEDor850‐nm(132mW/mm2),binationnear‐infrared(NIR)-andshuntleakagethroughthesemi‐(420lux)tosimulateareasonableindoororsubcu-work,wepresentmonolithicGaAs‐basedPVmodulesatthemillimetertaneouslow‐fluxconditionthatisapproximately1000timessmallerscaleoperatingunderlow‐fluxconditions(<10μW/mm2)-topowerIoTsystemsorbio‐implantablesensorswithouttherequire-dencebyvaryingtheirradianceinincrementsof10luxforwhite‐lightmentforDC‐DCvoltageup‐|EXPERIMENT3|RESULTSWeusedabaselinePVcellstructure(Figure1A)|Junctionbarrierisolationbeamepitaxy(MBE)basedonourpreviouslyreportedhigh‐efficiencysingle‐junctionGaAsPVcells,5wherethecriticallimitingfactorfromTheJ‐VcharacteristicsoffabricatedPVmoduleswithp‐GaAsandp‐exposedsidewall/‐FIGURE1Schematicdiagramsof(A)optimizedepitaxiallayerstructureofasinglecell,(B)devicestructureillustratingphotovoltaic(PV)celljunction,junctionbarrierisolation,andshuntleakagepath,and(C)equivalentcircuitmodelofthePVmodule[Colourfigurecanbeviewedat](PV)modules[]FIGURE3MeasuredJ‐Vcharacteristicsofphotovoltaic(PV)moduleswithGaAsandAlGaAsbarrierlayers(A)under850‐nmnear‐infrared(NIR)(B)parisonsareshowntosimulatedresults(dashed)withshuntleakageremoved[](p‐GaAsjunctionbarrierisolation),().WeextracteddiodeparametersfromsinglepowerconversionefficiencyforNIRilluminationdemonstratesaclearPVcellstosimulatetheJ‐Vcharacteristicsforseries‐%%,,‐GaAsandp‐‐‐‐,theoverallpowerconversioneffi-%%‐,%paresfavorablywiththesimulatedFIGURE4MeasuredJ‐%(PV)cellseriesconnectionand(inset)correspondingpowerconversionontheperformanceofmonolithicPVmodulesisfurtherillustratedefficiencyatthemaximumpowerpoint[ColourfigurecanbeviewedbythedependenceofJ‐Vonthenumberofseries‐],‐Vcharacteristicsshowsanobviousshuntleakagecharacteristic,‐VcurvesshowninFigure3arerepresenta-tiveofourtypicalmodulecharacteristics,whereanonlinearcurrentreductionisobservedinthe0to1Vrange,followedbyanapproxi--(PV)cellbaseandsemi‐insulatingsubstrateunderdarkshuntresistancebehaviorwithoutthenonlinearjunctionbarrierleak-conditionsforthreedifferentbarrierlayerstructures:Nobarrier,p‐agecurrentatlowvoltage,forwhichtheoriginisunclearandisatyp-GaAsjunction,andp‐[Colourfigurecanbeicalforthemajorityofsamplesthatwehavefabricated.]-rent(Figure3).Furthermore,forallthreecasesofjunctionbarrieriso-|Characteristicsofshuntleakagelation,weobserveaverylowshuntleakagecurrentthatisnearorbelowthenArangeandwouldnotbeexpectedtodramaticallyimpactWemeasuredshuntleakagecurrentbetweenn‐,theshuntleakagecurrentcharacter-PVcellswithoutmetalinterconnectsunderdarkconditionsfortheisticsunderdarkconditionscannotfullyexplainourobservedbehaviorthreedeviceisolationschemes,‐VcharacteristicfortheshuntcurrentleakageWesubsequentlymeasuredtheshuntleakagecurrentbetweenn‐withoutjunctionbarrierisolation,suggestingthatitislimitedbythecontactsofadjacentsinglePVcellsunderilluminationandobservedaresistanceofthesemi‐(Figure7).Thephoto‐activatedreductioninshuntleakagecurrentbyincorporatingp‐GaAsandp‐behaviormaybeinterpretedasanundesiredincreaseinphotoconduc-‐Vcharacteristictivityatthejunctionbarrierand/orexposedregionsofthesemi‐forthep‐GaAsjunctionbarrierhasanearexponentialdependence,-suggestingthatleakageismediatedbytheenergybarrierheightofdenceofthephoto‐activatedleakagecurrentmayexplainthenonlin-thep‐‐AlGaAsjunctionbarrierisolation,whichisForallthreejunctionisolationtechniques,‐,,thelargercurrentfortheadditionofp‐GaAsbarrierisolatio