表面修饰n型多孔硅的光致荧光特性

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1、Abstractquitediferent.ThemorphologyandthesurfacespeciesofthePSsampleswereexamined.TheoxidizingparametersoftheanodizationinthefollowingexperimentswerepreferredonthebasisofmeasuringthedependenceofPLproperties(peakposition,andmaxintensity,etc.)onanodizationconditions,suchastheanodizing

2、currentdensity,thetimeoftheanodization,theconcentrationofthesolution(mainlyofHF),andonthedopinglevelofthesubstrate.AsforthePLpropertiesofporoussiliconmodifiedbySnCl4withorwithoutSb-doping,therearetwokindsofshiftscomparedwiththeunmodifiedsamples.Blue-shiftofthePLpeakpositionwiththema

3、giwavelength540-560rim(green-emiting)forthelater(withoutSb-doping)andred-shiftofthePLpeakpositionwiththemaxwavelength650-690nm(red-emiting)fortheformer(withSb-doped)areobserved.Thequantumconfinementefect(QC)modelisobviouslynotenoughtoexplaintheaboveexperimentalresults.Thecomplexmode

4、lofluminescencecentersandquantumconfinementhasbeenproposedtointerprettheoriginofthegreenandred-emitingofthePSaftermodification.ThedeductionissupportedbyanalyzingthemorphologyandthesurfacespeciesofthemodifiedsamplesthroughAFM,SEM,andFTIR,XPS.Electron-holepairsarecreatedbyphoto-excita

5、tioninthenanoscalesiliconunits,andthenrecombinedradiativelyinthethinoxidelayers,givingagreenorredPLthroughtheluminescencecentersoutsidethenanoscalesiliconunits.ThephotoenergyfromtheluminescencecentersoftheundopedSn02modifiedsamples(about2.2eV)isrelativelylargerthanthatoftheSb-dopedo

6、nes(about1.9eV).UnderaUVlamp,ablueluminescence(maxwavelengthabout442notor420nm)bandcouldbeobservedafterthePSshadbeenimmersedinthemixedamineandthenoxidizedfor30s.AfterthePSmodifiedinthiswaywasstoredinairfornearlyoneyear,itsPLintensityhasincreasedabout30percent.FTIRspectrumshowsthatth

7、esurfaceofthemodifiedsampleswascoveredwithsiliconandoxygen,withnoremainingamine.Honeycomb-likemicrostructurewasfoundonthesurfaceofthemodifiedporoussiliconthroughSEMmicrographs,whichindicatesthehighporosityoftheblue-emittingsamples.Arrheniusplot(plotofnaturallogarithmofthePLintensity

8、,ln(PLintensity),ve