SimulationSimulationofofMultiple-JunctionMultiple-JunctionSolarSolarCellCellwithwithAPSYS:APSYS:ananApplicationApplicationGuideGuideCopyright2006CrosslightSoftwareInc.www.crosslight.com12DevicestructureExampledirectory:Apsys_example\Photo_sensitive\Triple_junction_cellIEEETrans.Elec.Devices,v.46,p.2116,19993ApsysmodelsrelatedtosolarcellsCompositiongradingandbuilt-inabsorptionspectrummodelformostcompoundsemiconductorsindefaultmateriallibrary.User-definedindex/absorptionspectrummayalsobeimported.Quantumtunneling(intra-andinter-bandtunneling)modelsuitableformultiplejunctionsolarcellsusingtunnelingjunctions.Allphysicalprocesses(carriergenerationandtransport)clearlyexplainedusingrealisticbanddiagrams.Incidentlightsmaybetreatedassimpleplanewavesblockedbycontactsandreflectedbymultilayeropticalcoatings.Opticalinterferenceswithinalllayersofthecellareincluded.Optionallyincidentlightmaybesimulatedbyray-tracingtoaccountforedgeeffects.4InGaPcellTunneljunctionGaAscellTunneljunctionGecellGraphicuserinterface(GUI)programLayerBuilder/Layer3Dmaybeusedtoconstructsolarcellswithease.5Treatmentoftunnelingjunctiona)Directuseof“zener”command.Advantage:physicallybasedmodel,noneedtofitdata.Disadvantage:moredifficulttoachieveconvergence.b)Useofempirical“equiv_tunnel_junc”commandwithresistancefittedtoexperimentor“zener”model.Advantage:numericallymorestable.$TJat1.02,madebyn(+)from1->1.02andp(+)from1.02->1.04equiv_tunnel_juncyrange=[11.151,11.169]equiv_tunnel_juncyrange=(14.94114.959)6Solarspectrum(imported)AM0isusedinthisexample7Banddiagramatequilibrium8BanddiagramwhenlightonSunlightGreenlines:quasi-Fermilevels9OpticalgenerationrateSunlight10Opticalpowerdistributionsunlight11I-VcurveExperimentdatatakenfromIEEETrans.Elec.Devices,v.46,p.2116,199912ConclusionsAdvancedmaterialmodelsofAPSYSmakeitsuitableforsimulationofsolarcellsbasedoncomplexcompoundsemiconductors.Flexibilityinmater