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Mn掺杂ZnO稀磁半导体纳米晶的制备与表征的中期报告.docx

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Mn掺杂ZnO稀磁半导体纳米晶的制备与表征的中期报告 Thisisamid-termreportonthepreparationandcharacterizationofMn-dopedZnOmagneticsemiconductornanocrystals. Introduction: Magneticsemiconductorsarepromisingmaterialsforpotentialapplicationsinspintronics,magneticstoragedevices,magneticsensors,etc.DopingZnOwithmagneticionslikeMncanintroducemagneticbehaviorintothesemiconductor,makingitamagneticsemiconductor.Inthisproject,Mn-dopedZnOnanocrystalsaresynthesizedbyasol-gelmethod,andtheirstructural,optical,andmagneticpropertiesarecharacterized. Experimental: Zincacetatedihydrateandmanganeseacetatetetrahydratewereusedastheprecursors.Ethanolwasusedasthesolvent,anddiethanolamineandwaterwereusedasthestabilizers.Thesynthesisprocessinvolvedthefollowingsteps:(1)Dissolvingzincandmanganeseprecursorsinethanol;(2)Addingdiethanolamineandwatertothesolution;(3)Agingthesolutionatroomtemperaturefor24hours;(4)Dryingthegelat60°Cfor2hours;(5)Annealingthegelat600°Cfor2hoursunderanitrogenatmosphere. ThesynthesizedMn-dopedZnOnanocrystalswerethencharacterizedbyvarioustechniques:XRDforcrystalstructure,UV-Vis-NIRspectroscopyforopticalproperties,TEMformorphology,andSQUIDmagnetometerformagneticbehavior. ResultsandDiscussion: XRDanalysisshowedthatthesynthesizedMn-dopedZnOnanocrystalshadawurtzitecrystalstructure,withslightlatticeexpansionduetotheMnsubstitution.TEMimagesshowedthatthenanocrystalsweresphericalinshapeandhadanaveragesizeofaround20nm. UV-Vis-NIRspectroscopyshowedthattheopticalbandgapofthenanocrystalsdecreasedwithincreasingMndoping,indicatingthatMndopingincreasedthechargecarrierconcentration,leadingtothereductionofthebandgap. ThemagneticpropertiesoftheMn-dopedZnOnanocrystalsweremeasuredbySQUIDmagnetometer.Theresultsshowedthatthenanocrystalsexhibitedferromagneticbehavioratroomtemperature,withamagneticmomentofaround0.5emu/g.TheferromagnetismcanbeattributedtotheMndopants,whichintroducedlocalmagneticmomentstotheZnOlattice. Conclusion: Mn-dopedZnOnanocrystalsweresuccessfullysynthesizedbyasol-gelmethod,andtheirstructural,optic