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1、摘要納米硅晶有許多不同于單晶硅的結(jié)構(gòu)、光學(xué)及光電性能,它在發(fā)光器件、光探測(cè)器件、光電集成器件以及傳感器等領(lǐng)域有廣闊的應(yīng)用前景。本實(shí)驗(yàn)研究了90年代以來成為硅基納米材料主要代表的多孔硅的制備方法、生長(zhǎng)機(jī)理和發(fā)光機(jī)理。本論文采用電化學(xué)方法和化學(xué)刻蝕方法制備了不同條件下的多孔硅,并測(cè)試了其光致發(fā)光性能,在紫外線激發(fā)或陽極偏壓的條件下,可觀測(cè)到強(qiáng)的紅、橙、黃、綠光的發(fā)射。實(shí)驗(yàn)發(fā)現(xiàn),隨著電流密度的增大,時(shí)間的延長(zhǎng)和電解液濃度的降低,多孔硅發(fā)光峰位會(huì)有藍(lán)移。由于多孔硅的發(fā)光不穩(wěn)定,在空氣中放置一段時(shí)間后會(huì)發(fā)生衰減,本實(shí)驗(yàn)首次采用一種簡(jiǎn)便的方法對(duì)多
2、孔硅進(jìn)行處理,得到了發(fā)光強(qiáng)度高、發(fā)光性能穩(wěn)定的多孔硅。目前,多孔硅的光致發(fā)光機(jī)理、電致發(fā)光機(jī)理和多孔硅的形成和生長(zhǎng)機(jī)理目前尚無定論。本實(shí)驗(yàn)研究認(rèn)為對(duì)發(fā)射穩(wěn)定的紅、橙光的多孔硅量子限制效應(yīng)起主導(dǎo)作用,表面態(tài)起輔助作用,而且對(duì)兩個(gè)不同的發(fā)光峰位,受量子限制效應(yīng)的影響程度是不同的;對(duì)于發(fā)不穩(wěn)定的黃、綠光樣品,納米晶的量子限制效應(yīng)作為源頭,而表面態(tài)起主導(dǎo)作用。本實(shí)驗(yàn)為電解液接觸多孔硅電致發(fā)光是由Si-H鍵氧化而注入電子提供了新的實(shí)驗(yàn)依據(jù)。另外,本文還結(jié)合多孔硅的制備參數(shù),討論了多孔硅的生長(zhǎng)過程和發(fā)光機(jī)理之間的關(guān)系,深入分析了多孔硅的形成機(jī)理和
3、發(fā)光機(jī)理。關(guān)鍵詞:多孔硅光致發(fā)光電致發(fā)光表面鈍化量子限制效應(yīng)表面態(tài)ABSTRACTSiliconnanocrys詛lscallemitvisiblelightandexhibitnoveloptoelectronicpropertiesandspecialstructure.Itshowshighpotentialonlight—emittingdevices,photodetector,optoelectronlcdevicesandsensor.Theporoussiliconisarepresentofsilicon—based
4、nanometermaterial,inthisdissertation,thepreparationprocess,themechanismofformationofporoussiliconanditsluminescenceweresystematicallyinvestigated.Theporoussiliconwasfabricatedbyelectrochemicalandchemicalmethodsandthephotoluminescencepropertiesweremeasured.Intensivered,o
5、range,yellow,greenlightCanbeseenwhenporoussiliconwasirradiatedunderultravioletlightorworkaspositivebiases.Itwasdiscoveredthatwiththeincreaseofthecurrentdensity,anodizingtimeandthereductionofHFconcentration,thepeaksofPLshowstheblueshift.WhenPSareexposedtotheair,theintens
6、ityofPLwilldecrease.AnovelandeasymethodWasadoptedtoimprovetheintensityandstabilityofthephotoluminescence.Themechanicsofphotoluminescence,eleclToluminescenceandR珊ationprocessarestillinargument.Itwasdiscoveredthatthestableredandorangelight。emittingWascausedbyquantumconfin
7、ementandthesurfacestateplayedanassistantrole;theunstableyellowandgreenlight-emittingwasmainlycausedbysurfacestateandthequantumconfinementplayedanassistantrole.TheelectroluminescenceofporoussiliconinHClacidatpositivestemmedfromtheoxidationofSi—HbondonthesurfaceofPS.Wepro
8、vidednewprooffortllistheory.Inaddition,therelationbetweentheformationprocessand協(xié)emechanismofphotoluminesceneeW