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1、摘要本文綜述了SnO2氣敏薄膜國內(nèi)外研究現(xiàn)況及發(fā)展趨勢,綜合考慮各種制備薄膜的方法,本實驗采用工藝簡單,成本低廉的薄膜制備方法——溶膠-凝膠法。本文首先制備了純SnO2氣敏薄膜,研究了薄膜厚度對靈敏度的影響及薄膜電阻與氣體濃度的關系,采用針對SnO2薄膜提出的氣體擴散模型和受到廣泛認同的晶界勢壘模型對實驗現(xiàn)象進行了分析。實驗結果表明,氣敏薄膜的Sb元素摻雜會使薄膜的靈敏度降低,本文通過類比分析,將晶界勢壘模型和異質(zhì)結模型結合,解釋推導了施主摻雜對氣敏性能的影響。本文實驗制備了SnO2基H2S氣敏薄膜,為了提高其氣敏性能,對溶膠-凝膠法制備SnO2薄膜的燒結溫度和CuCl2的摻雜量進行了探索。
2、文中通過X射線衍射儀、差熱熱失重分析儀、場發(fā)射掃描電鏡和氣體響應測試,對SnO2納米薄膜性能進行表征,確定了薄膜的最佳燒結溫度為550℃,CuCl2的最佳摻雜量為3mol%。測試結果表明,制得的SnO2薄膜在室溫下具有很好的響應特性,對于68.5ppm的H2S,其靈敏度可達3648,屬國內(nèi)外領先水平。隨著工作溫度的升高,氣敏薄膜呈現(xiàn)出較好的恢復特性。XRD和SEM分析表明,薄膜是由SnO2納米晶構成的多孔薄膜,晶粒的平均尺寸大小約為25nm。本文對SnO2基CO薄膜的制備進行了初步探索。分別采用溶膠凝膠法和固相法對SnO2進行了PdO和In2O3摻雜,并利用催化劑的溶解溢出模型和費米能級控制
3、模型對實驗結果進行分析和解釋。關鍵詞:二氧化錫;氣敏機理;溶膠-凝膠法;硫化氫IAbstractTindioxide,asortofn-typesemiconductormaterial,iswidelyusedtofabricategassensordevices.DomesticandforeignresearchprogressesinSnO2thinfilmswerereviewedinthispaper.Sol-Geldip-coatingmethodwasadoptedbecauseofitsadvantages,suchaslowcostandeasydepositionoft
4、hinfilms.Firstly,pureSnO2thinfilmswerefabricated.Therelationshipbetweenthethicknessandsensitivitywasstudied.Inordertoanalyzetheresults,gasdiffusionmodelwasemployed.Afterthat,therelationshipbetweenresistanceofthinfilmsandgasconcentrationwasdiscussedandtheboundarybarriercontrolmodelwasusedtoexplainth
5、eresults.Atlasttheboundarybarriercontrolmodelandheterojunctionmodelwerecoalescedtodeducetherelationshipbetweenthedonorconcentrationandsensorresponses.ThereasonwhySbdopingdecreasedthesensitivitywasgivenafterthededuction.Sol-geldipcoatingtechniquewasemployedtoprepareCu-dopedSnO2thinfilms,whichwereabl
6、etodetectH2Sgasatroomtemperaturewithhighsensitivityandrevealedfastresponsecharacteristics.Thehighestsensorresponse(theratioofresistanceinairversusinH2S)was3648underH2Sconcentrationof68.5ppmatroomtemperature.Recoverabilityofthethinfilmsappearedwhenthetemperatureraisedto50℃.Thefilmswereanalyzedbymean
7、sofXRDandthedriedgelpowderwasstudiedbyTG-DTAtest.InfluencesofsinteringtemperatureanddopinglevelontheH2Sresponsewerediscussed.TheaveragegrainsizeoftheSnO2wasabout25nm.ThemethodofpreparingSnO2thinfilmswhichus