硅量子點能帶結構的分子動力學研究.pdf

1、東南大學碩士學位論文硅量子點能帶結構的分子動力學研究姓名：邱崢嶸申請學位級別：碩士專業(yè)：電子科學與技術；微電子學與固體電子學指導教師：于虹20110419AbstractSolarenergyisthecleanestrenewableenergyAsarlimportantsolarphotovoltaicelleTgyconversationdevice，ithasattractedmuchattentionrecentlyHowe

2、verthecostofsolarcellsisveryhigh，andtheefficiencyofenergyconversionofthecurrentsolarcellsismuchlowerthanthetheoreticalpredictionn圯uniquepropertyofquantumdotisthattheenergybandstructureandtheabsorptionspectrumwillchangeas

3、thesizeofthequantumdotchangesAsweallknownsolarcellsarebasedonPNjunctionTherefore，studyingthepropertiesofborondopedandphosphorusdopedsiliconquantumdotsisverynecessaryLotsofexperimentsandtheoreticalcalculationshavebeendone

4、tostudythebandgapandtheopticalpropertiesofsiliconquantumdotsHoweverthediameterofsiliconquantumdotissosmallthatitistoodifficulttobemanufacturedpreciselyinexperimentThentheoreticalcalculationbecomesmorenecessaryMaterialsSt

5、udioprovidesuswithagoodtheoreticalcomputingplatformThemodelsofsiliconquantumdotsaleestablishedintheCASTEPmoduleofMaterialsStudio，andthebandsffuoRffeandopticalpropertiesofsiliconquantumdotsindifferentsizeshavebeencalculat

6、edwithdifferentalgorithmsanddifferentaccuracyTheresultsshowthatthebandgapincreasesobviouslyandtheellergylevelsinconductionbandbecomesparser麗tllthedecreasingdiameterofsiliconquantumdotItalsocanbeseenthatwhenthediameterofs

7、iliconquantumdotisgreaterthan20Athebandgapofsiliconquantumdotisreducedverylittle，andthenreachesaconstantvalueWiththedecreasingsizeofsiliconquantumdots，themainabsorptionpeakisblueshiftedtheabsorptionisincreasedtheabsorpti

8、onspell“urnbroadensandtheabsorptionenergylevelsbecomemoreandmoredispersedCompared、珩tlltheLDAcalculationstheresultsofbandstructureandabsorptionspectracalculated謝tllsxLDAaremoreaccurateBoththeresultsofbandstructureandthere

9、sultsofabsorptionspectrahavelittledifferencewhentheaccuracymediumandfinearesetThemodels&peaatomsBorPinSis7H76areset叩Differentlocationsanddifferentdopingconcentrationsarcconsideredinoill“researchWhentheatomsSiwhichintheou

10、termostlayerofthesiliconquantumdotandhaveonedanglingboIldarcreplacedbyBorPtheenergyofsiliconquantumdotisthelowestThedopingenergylevelsareintroducedintothebandgapof8i$7H76byB11艙dopingenergylevelsbocolnemoreinthebandgapofS

11、i87H76andthemainabsorptionpeakofSis7H76isblueshifted鵲theconcentrationofBincreasesHoweverthedopingenergylevelsareintroducedintotheconductionbandofSisTH76byPThehigherthedopingconcentrationofPisthegreatertheabsorptionofSi$7

12、H76isOverall，thebandgapandtheabsorptionspectrumofsiliconquantumdotscanbeadjustedbyregulatethesizeorthedopingconcentrationofsiliconquantumdotsTllisuniqueproperty鋤beusedtoextendtheabsorption$pectruRlofthesolarcellbymixings

13、iliconquantumdots、加tlldifferentsizesThereforethefullspecl：rumofthesunlightmaybeutilizedmoreefficientlyandtheconversationrateofthesolarcellswinbe丘lrtherimprovedKeywords：siliconquantumdots，quantumconfinementeffect，bandstru