简介:Accordingtothewell-establishedlight-to-electricityconversiontheory,resonantexcitedcarriersinthequantumdotswillrelaxtothegroundstatesandcannotescapefromthequantumdotstoformphotocurrent,whichhavebeenobservedinquantumdotswithoutap–njunctionatanexternalbias.Here,weexperimentallyobservedmorethan88%oftheresonantlyexcitedphotocarriersescapingfromInAsquantumdotsembeddedinashort-circuitedp–njunctiontoformphotocurrent.Thephenomenoncannotbeexplainedbythermionicemission,tunnelingprocess,andintermediate-bandtheories.Anewmechanismissuggestedthatthephotocarriersescapedirectlyfromthequantumdotstoformphotocurrentratherthanrelaxtothegroundstateofquantumdotsinducedbyap–njunction.Thefindingisimportantforunderstandingthelow-dimensionalsemiconductorphysicsandapplicationsinsolarcellsandphotodiodedetectors.
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简介:ChargedparticlediagnosticsisoneoftherequiredtechniquesforimplosionarealdensitydiagnosticsattheSG-IIIfacility.Severalprotonspectrometersareunderdevelopment,andsomepreliminaryarealdensitydiagnosticshavebeencarriedout.Theresponseofthekeydetector,CR39,tochargedparticleswasinvestigatedindetail.Anewtrackprofilesimulationcodebasedonasemi-empiricalmodelwasdeveloped.TheenergyresponseoftheCR39detectorwascalibratedwiththeacceleratorprotonsandalphasfroma241Amsource.AprotonspectrometerbasedonthefilteredCR39detectorwasdeveloped,andD–Dprimaryprotonmeasurementswereimplemented.Asteprangefilterspectrometerwasdeveloped,andpreliminaryarealdensitydiagnosticswascarriedout.AwedgedrangefilterspectrometerarraymadeofSiwithahigherresolutionwasdesignedanddevelopedattheSG-IIIfacility.AparticleresponsesimulationcodebytheMonteCarlomethodandaspectraunfoldingcodeweredeveloped.Thecapabilitywasevaluatedindetailbysimulations.