合成温度和N_2/O_2流量比对碳纤维衬底上生长的SnO_2纳米线形貌及场发射性能影响  

Effect of synthesis temperature and N_2/O_2 flow on morphology and field emission property of SnO_2 nanowires

作　　者：马立安[1] 郑永安[1] 魏朝晖[1] 胡利勤[2] 郭太良[2] 

机构地区：[1]福建工程学院材料科学与工程学院,福州350108 [2]福州大学光电显示技术研究所,福州350108

出　　处：《物理学报》2015年第23期331-339,共9页Acta Physica Sinica

基　　金：福建省自然科学基金(批准号:2012J01185);福州大学场致发射显示教育部工程研究中心开放基金(批准号:KF1016);福州市科技局项目(批准号:2014-G-81)资助的课题~~

摘　　要：采用化学气相沉积法系统研究了合成温度和N_2/O_2流量对生长在碳纤维衬底上的SnO_2纳米线形貌及场发射性能的影响规律.利用扫描电镜(SEM)、透射电镜(TEM),X射线衍射(XRD)及能谱仪(EDS)对产物细致表征,结果表明,SnO_2纳米线长径比随反应温度的升高而增大;随N_2/O_2流量比值的增大先增大后变小,场发射测试表明,合成温度780?C,N_2/O_2流量比为300:3时SnO_2纳米线阵列具有最佳的场发射性能,开启电场为1.03 V/μm,场强增加到1.68 V/μm时,发射电流密度达0.66 m A/cm^2,亮度约2300 cd/m^2.A large amount of tin oxide（SnO2） nanowire arrays were synthesized on the flexible conductive carbon fiber substrate by thermal evaporation of tin powders in a tube furnace.The temperature,as well as the flow rate of the carrier N2 gas and the reaction O2 gas,plays an important role in defining the morphology of the SnO2 nanowires.Morphology and structure of the as-grown SnO2 samples are characterized by scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,energy dispersive spectroscopy（EDS）,and X-ray diffraction（XRD）.Results show that all the samples possess a typical rutile structure,and no other impurity phases are observed.The morphology changes from rod to wire with the increase of reaction temperature.Ratio of length to diameter of the nanowires increases first and then decreases with the flow ratio of N2/O2 gas.The optimum synthesis conditions of SnO2 nanowire are：reaction temperature 780？C,N2 and O2flow rates being 300 sccm and 3 sccm respectively.In our growth process,the nanowire grows mainly due to the vapor-liquid-solid（VLS） growth process,but both the VLS process and surface diffusion combined with a preferential growth mechanism play the important role in morphology evolution of the SnO2.Field emission measurements for Samples 1- 6 are carried out in a vacuum chamber and a diode plate configuration is used.Relationship between the growth orientation,aspect ratio,density and uniformity of the arrays and field emission performances will be investigated first.Results reveal that the field emission performance of SnO2 nanostructures depends on their morphologies and array density.The turn-on electric field（at the current density of 10 μA/cm2） decreases and the emission site density increases with tin oxide array density,and the turn-on electric field of Sample 5（synthesized at 780？C,nitrogen and oxygen flow rates being 300 sccm and 3 sccm respectively） is about 1.03 V/μm at a working distance of 500 μm.By comparison,for the turn-on electric fie

关 键 词：化学气相沉积 纳米氧化锡 形貌调控 场致发射 

分 类 号：TB383.1[一般工业技术—材料科学与工程] O614.432[理学—无机化学]