锌衬底上直接生长密度可调的氧化锌纳米棒阵列和场发射特性

在锌衬底上制备了取向生长、形貌各异、不同密度的氧化锌纳米棒阵列.研究发现,氧化锌纳米棒在温度低于70℃、适量的碱性溶液、大气压下能够在锌衬底上大规模制备,并且氧化锌纳米棒的直径,在锌衬底上的密度和形貌完全依赖于氢氧化钠和硝酸锌的浓度.场发射测试表明:氧化锌纳米棒阵列开启电场较低(电流密度达1μA/cm2时场强仅为3.8 V/μm),显示了氧化锌纳米棒阵列在场发射方面的潜在应用.     

生长时间对氧化锌纳米棒发光性能的影响

为了研究氧化锌纳米棒的生长机理,先用脉冲激光沉积方法在玻璃衬底上制备一层氧化锌薄膜作为种子层,然后用水热法在种子层上生长氧化锌纳米棒,研究了不同反应时间对其结构、形貌及发光特性的影响。利用X射线衍射仪和扫描电子显微镜测定样品的结构和形貌,用自组建的光致发光系统对样品的光致发光光谱进行了测量。结果表明,氧化锌纳米棒沿c轴高度取向并呈六角纤锌矿结构;随着生长时间的增加,氧化锌纳米棒结晶质量明显改善,纳米棒均匀、致密性和取向性均提高,样品的缺陷发光增强而激子发光减弱。     

氧化锌与定向碳纳米管复合纳米结构设计与场发射性能研究

考虑到目前方法制备出的氧化锌碳纳米管复合结构多为随机取向,会在一定程度上影响其场发射性能,例如发射电流稳定性、寿命等性能方面,提出了一种氧化锌纳米线与定向碳纳米管复合纳米结构阵列的制备方法,并制备出了相应的结构体.模拟计算和测试结果表明文中制备出的复合纳米结构阵列改善了单一纳米结构的场发射性能.与单纯碳纳米管阵列相比,...     

不同结构的一维纳米ZnO的制备及其性能研究

采用热蒸发法在不同的条件下制备出了阵列状和铅笔状的-维纳米ZnO.利用X射线衍射、扫描电子显微镜、场发射测试仪、光致发光谱对ZnO纳米材料的结晶质量、形貌及场发射性能进行了分析.阵列状氧化锌纳米结构c轴择优取向良好,铅笔状氧化锌纳米结构场发射性能良好.两种纳米结构的室温光致发光谱均显示出了强紫外发射峰和弱绿光发射峰.     

ZnO纳米棒的图形化生长及其场发射特性

介绍了用氢离子注入技术和阳极腐蚀方法在硼掺杂p-(100)型硅晶片上制备图形化的纳米硅(SiNC)薄膜工艺,并在这种图形化衬底上成功生长了图形化的ZnO纳米棒.场发射测试表明制备的ZnO纳米棒具有良好的场发射性能,即具有较低的开启电场和阈值电场,较高的发射点密度.     

ZnO纳米棒的图形化生长及其场发射特性

介绍了用氢离子注入技术和阳极腐蚀方法在硼掺杂p-(100)型硅晶片上制备图形化的纳米硅(SiNC)薄膜工艺,并在这种图形化衬底上成功生长了图形化的ZnO纳米棒.场发射测试表明制备的ZnO纳米棒具有良好的场发射性能,即具有较低的开启电场和阈值电场,较高的发射点密度.     

ZAO基底水热法制备ZnO纳米阵列及其形貌特征

采用水热法,在ZAO透明导电薄膜衬底上制备了不同形貌的ZnO纳米阵列.用SEM、紫外可见光分光光度计、四探针测试仪等测试手段对ZnO纳米阵列的形貌结构和物理特性进行了表征和测试.结果表明,不添加任何催化剂,0.075 M的乙酸锌水溶液中,90℃水温时可生长出形状规则的氧化锌纳米棒;相同的温度下,等摩尔浓度(0.05 M)的乙酸锌和六亚甲基四胺水溶液中,可生长出氧化锌纳米片阵列.光电性能测试表明所制备的ZAO/氧化锌纳米阵列具有良好的光透过性和导电性.     

水热法制备氧化锌纳米棒

以Zn(NO3)2·6H2O,Zn,CTAB(十六烷基三甲基溴化铵)和N2 H4·H2O等为原料,采用水热法和改进的水热法,在180℃制备了氧化锌(ZnO)纳米棒束及纳米棒阵列薄膜.用XRD,SEM,FE-SEM及HR-TEM对样品进行了表征.具有六方纤锌矿结构的ZnO纳米棒直径在40～80nm左右.以负离子配位多面体生长基元理论讨论了ZnO晶体的生长过程及反应条件对ZnO形貌的影响.样品光致发光谱测试结果表明,纳米棒束、阵列具有强的紫紫外光发射峰和不同强度的蓝绿光发射峰.     

水热法制备氧化锌纳米棒

以Zn(NO3)2·6H2O,Zn,CTAB(十六烷基三甲基溴化铵)和N2 H4·H2O等为原料,采用水热法和改进的水热法,在180℃制备了氧化锌(ZnO)纳米棒束及纳米棒阵列薄膜.用XRD,SEM,FE-SEM及HR-TEM对样品进行了表征.具有六方纤锌矿结构的ZnO纳米棒直径在40～80nm左右.以负离子配位多面体生长基元理论讨论了ZnO晶体的生长过程及反应条件对ZnO形貌的影响.样品光致发光谱测试结果表明,纳米棒束、阵列具有强的紫紫外光发射峰和不同强度的蓝绿光发射峰.     

ZnO纳米棒的图形化生长及其场发射特性

介绍了用氢离子注入技术和阳极腐蚀方法在硼掺杂p-(100)型硅晶片上制备图形化的纳米硅(SiNC)薄膜工艺，并在这种图形化衬底上成功生长了图形化的ZnO纳米棒. 场发射测试表明制备的ZnO纳米棒具有良好的场发射性能，即具有较低的开启电场和阈值电场，较高的发射点密度.     

表面形貌对定向氧化锌阵列场致发射性能的影响

采用热蒸发的方法生长不同形貌的ZnO纳米材料。通过调节反应温度和氧气流量,生长了梳状ZnO ,ZnO纳米针和ZnO纳米柱状。场致发射测试结果表明一维纳米ZnO材料的表明形貌对其开启电场和发射电流有很大的影响。ZnO纳米柱阵列的开启电场最低,电流密度最大。这是由于它与衬底的良好接触以及较弱的场屏蔽效应。实验结果表明ZnO纳米柱阵列是一种优良的场致发射器件的冷阴极材料。     

Influence of morphologies on the field emission performance of oriented ZnO nano-arrays

Different morphologies of comb-like ZnO and oriented ZnO nano-arrays such as ZnO nanoneedles and ZnO nanorods were synthesized by using flexible thermal evaporation method via simply adjusting the temperature and oxygen content.The ZnO nanorods arrays have the lowest turn-on field,highest current density and the largest emission efficiency owning to its good contact with the substrate and relatively weaker field screening effects. The experiments show that the morphologies and orientation of one-dimensional(1D) ZnO nanomaterials have considerable effects on the turn-on field and the emission current density,and the nanoarray also contributes to electrons emission.The results could be valuable for the application of ZnO nanorod arrays as cathode materials in field emission based devices.     

Processing temperature dependent morphological and optical properties of ZnO nanorods

Zinc Oxide (ZnO) nanorods were synthesized by thermal decomposition of zinc acetate dihydrate at various processing temperatures. The morphology of samples, examined using transmission electron microscopy and field emission scanning electron microscopy, revealed large variations in length and diameter of nanorods. As temperature was increased from 300 °C to 450 °C, ZnO nanocrystal morphology changed from wire-like to rod-like. This morphology change is a result of competition between nucleation and growth rate in the vapor–solid growth mechanism of nanorods. Photoluminescence spectrum of the nanorods showed both band edge emission as well as native defect related visible emission. Relative intensity of UV and visible emission indicated crystal quality of the nanorods, the ratio increased upto 400 °C and deteriorated at higher processing temperature. It is argued that process induced defects dominate at processing temperatures ≤400 °C, whereas equilibrium concentration of native defects is high at temperatures >400 °C.     

ZnO Nanorod Arrays as Electron Injection Layers for Efficient Organic Light Emitting Diodes

Nanostructured oxide arrays have received significant attention as charge injection and collection electrodes in numerous optoelectronic devices. Zinc oxide (ZnO) nanorods have received particular interest owing to the ease of fabrication using scalable, solution processes with a high degree of control of rod dimension and density. Here, vertical ZnO nanorods as electron injection layers in organic light emitting diodes are implemented for display and lighting purposes. Implementing nanorods into devices with an emissive polymer, poly(9,9‐dioctyluorene‐alt‐benzothiadiazole) (F8BT) and poly(9,9‐di‐n‐octylfluorene‐alt‐N‐(4‐butylphenyl)dipheny‐lamine) (TFB) as an electron blocking layer, brightness and efficiencies up to 8602 cd m^?2 and 1.66 cd A^?1 are achieved. Simple solution processing methodologies combined with postdeposition thermal processing are highlighted to achieve complete wetting of the nanorod arrays with the emissive polymer. The introduction of TFB to minimize charge leakage and nonradiative exciton decay results in dramatic increases to device yields and provides an insight into the operating mechanism of these devices. It is demonstrated that the detected emission originates from within the polymer layers with no evidence of ZnO band edge or defect emission. The work represents a significant development for the ongoing implementation of ZnO nanorod arrays into efficient light emitting devices.     

热氧化磁控溅射金属锌膜制备ZnO纳米棒

利用射频磁控溅射技术在Si(111)衬底上制备金属锌膜 ,在空气中退火热氧化合成了一维ZnO纳米棒。用X射线衍射 (XRD) ,扫描电子显微镜 (SEM) ,透射电子显微镜 (TEM)和光致发光谱 (PL)对样品进行了结构、形貌及光学特性分析。结果表明 :ZnO纳米棒为六方纤锌矿结构单晶相 ,直径在 30～ 6 0nm左右 ,其长度可达5～ 8μm左右。在 2 80nm波长光激发下 ,有很强的 372nm带边紫外光发射和较微弱的 5 16nm深能级绿光发射 ,说明合成的单晶ZnO纳米棒的质量较高     

热氧化磁控溅射金属锌膜合成一维ZnO纳米棒

利用退火热氧化射频磁控溅射金属锌膜的方法在Si(111)衬底上制备了一维ZnO纳米棒,同时用多种测试手段对样品的晶体结构、表面形貌和光学性能进行了研究.XRD,SEM和TEM的测试结果表明,ZnO纳米棒为单晶相六方纤锌矿结构,呈头簪状向外发散生长,直径在30～60nm左右,其长度可达几μm.PL谱测试结果表明:在波长为280nm光的激发下,在372nm处有强的近带边紫外光发射和516nm处的较微弱深能级绿光发射.说明合成的一维ZnO纳米棒的结晶质量和光学性能优良.     

Influence of ammonia concentration on the microstructure,electrical and raman properties of low temperature chemical bath deposited ZnO nanorods

Nanostructured zinc oxide synthesized using an easy and low temperature chemical bath deposition method are among the most promising low cost semiconducting nanostructures investigated for a variety of applications. We successfully report the effects of ammonia solution in the growth of ZnO nanorods at a temperature of 60 °C. Successive addition of ammonia altered the degree of supersaturation of the growth solution, causing a significant deviation in the morphology and crystal orientation of ZnO nanorods. Field emission scanning Electron Microscopy images revealed changes in surface morphology of ZnO nanorods with respect to addition of specific amounts of ammonia. X-ray diffraction analysis revealed wurtzite crystal structure of ZnO which was further supported by X-ray photoelectron studies, optical absorbance and Raman spectra that also revealed the existence of wurtzite ZnO. The current-voltage measurement showed the electrical properties of the synthesized ZnO nanorods. The vertically grown nanorods with flat tops, effect more rectifying Schottky contacts to be realized on comparison to needle like structures.     

AZO种子层朝向对ZnO纳米棒形貌和发光特性的影响

在水平管式炉中,采用热蒸发锌粉的方法,在镀有掺铝氧化锌(AZO)薄膜的石英基片上制备了大量高密度的ZnO纳米棒,AZO膜面分别正对和背对锌源。利用扫描电子显微镜、X射线衍射仪以及荧光光谱仪分析AZO膜面朝向对ZnO纳米棒的形貌、微结构及光学性能的影响。结果表明,不同朝向的AZO膜面上所生长的纳米棒具有相似的形貌和微结构。保温时间10min样品的氧空位的缺陷态发光为绿光,强度较强;保温时间15min样品的纳米棒长度较长、相对垂直衬底,其近带边发光较强,氧间隙的缺陷态发光较弱。正对锌源衬底上且保温时间15min样品的近带边发光最强,且缺陷态发光最弱。