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1、脈沖激光法制各ZnO薄膜及其光學(xué)性質(zhì)的研究摘要ZnO是一種寬帶隙的半導(dǎo)體材料,具有六方纖鋅礦結(jié)構(gòu),室溫下它的能隙寬度為3.37eV,激子束縛能高達60meV,可實現(xiàn)室溫下的紫外受激發(fā)射,在表面聲波器件、紫外光探測器、壓敏器件和紫外激光器件等領(lǐng)域具有廣闊的應(yīng)用前景。ZnO薄膜具有良好的透明導(dǎo)電性、壓電性、光電性、氣敏性、壓敏性、且易于與多種半導(dǎo)體材料實現(xiàn)集成化。本文通過采用一種先進的薄膜制備方法一脈沖激光沉積在si(100)上制備了ZnO薄膜,研究了制備參數(shù)(如襯底溫度、氧壓、激光脈沖能量等)對樣品相關(guān)性質(zhì)的影響。通過x射線衍射(XRD)灝J試分析了樣品的結(jié)構(gòu)特性,結(jié)果表明所有樣品均有C.軸
2、取向的生長特性,隨著襯底溫度和氧壓的升高,ZnO(002)峰的半高寬減小,薄膜的質(zhì)量有所提高。利用原子力顯微鏡(AFM)和掃描電子顯微鏡(SEM)對樣品表面形貌進行表征,結(jié)果表明所有樣品均垂直于襯底生長,且大部分表面晶粒尺寸均勻,在襯底溫度為600℃時,薄膜出現(xiàn)了向ZnO納米棒陣列轉(zhuǎn)化的趨勢。通過對樣品的光致發(fā)光(PL)特性測試分析可知,所有樣品均出現(xiàn)較強的紫外發(fā)射和可見光(深能級)發(fā)射,而Mg摻雜的ZnO薄膜的PL譜測試卻只出現(xiàn)了較強的紫外發(fā)射,深能級發(fā)射很弱,說明適量有效的摻雜能減少ZnO薄膜中的缺陷。通過對樣品的橢圓偏振光譜測試分析可知,隨著襯底溫度的升高,樣品的折射率和消光系數(shù)均隨
3、波長增長呈遞減趨勢,且在波長為500nm后遞減的幅度變小。關(guān)鍵詞:氧化鋅;脈沖激光沉積;X射線衍射;原子力顯微鏡;掃描電子顯微鏡;光致發(fā)光;橢圓偏振光譜儀PreparationandOpticalPropertiesofZnOFilmsGrownbyPulsedLaserDepositionAbstractZincOxide(ZnO)isasemiconductorwithawidedirectbandgapof3.37eVatroomtemperatureandhighexeitonbindingenergyof60meV.ZnOfilmshavemanyrealizedandpoten
4、tialapplicationssuchassurfaceacousticwavedevices,ultravioletphotodetectors,piezoelectricdevices,varistors,etc.ZnOthinfilmshaveexcellenttransparentconductivity,piezoelectricity,photoelectricity,gassensitivityandpresssensitivity.Inmythesis,alladvancedfilmpreparationtechniquewasusedfortheZnOthinfilmp
5、reparationontheSi(100)substrates,thepreparationparameterseffectonthefilmswasalSOdiscussed.ThecrystallinityofthefilmsWasanalyzedbytheXrayDiffraction.111espeetmmshowthatallthefilmshavetheC-axisorientandthe(002)peakSFHWMdecreasesasthesubstmtetemperatureandthe02pressureriseThesurfacetopographyofthefil
6、mswereobservedbyAFMandSEM,fromtheimages,itCanbefoundthatallthefilmsgrewperpendiculartothesubstrates,anddimensionofthesurfacegraindistributesuniformly.Thefilmgrownatsubstratetemperature600℃showthetrendoftransformingintoznOnanorodarray.n坨roomtemperaturephotoluminescencespectraoftheZnOsamplesshowastr
7、ongUVemissionaswellasadeepenergylevelemission.ButtheMgdopedZnOfilmsshowintenseUVemission.ThefeebledeepenergylevelemissiontellsUStheZnOfilmsdopedmoderatelyhavelessdefects.Fromthemeasuredresultofspectroscopicellips