ZnO纳米棒的电沉积生长方法研究

用含有硝酸锌(Zn(NO3)2)和六次甲基四胺(HMTA,C6H12N4)的电解液,在低温环境下采用阴极电沉积法在ITO玻璃上成功合成了氧化锌(ZnO)纳米棒阵列。系统研究了电压、前驱物(Zn2+)浓度、温度和种子层等参数对ZnO纳米棒形貌结构的影响,实现了ZnO纳米棒的可控制备。结果表明,在有种子层的情况下,当电压为-0.9V、Zn2+浓度为0.01M、温度为75℃条件下生长的ZnO纳米棒c-轴择优取向好、尺寸均匀(80~100nm),且在380~750nm的可见光波长范围内的透射率达到80%。     

Co掺杂ZnO纳米棒的电沉积法制备及其光学性能

在Zn（NO3）2和Co（NO3）2溶液中,以柠檬酸作为络合剂,采用阴极恒电位沉积法直接在ITO衬底上制备出纯ZnO和Co掺杂ZnO（ZnO∶Co）纳米棒阵列膜。采用X射线衍射、扫描电镜和能量色散谱对所制备ZnO纳米棒的晶体结构和表面形貌进行了表征,利用光致发光光谱研究了样品的发光性质。结果表明：所制备的ZnO纳米棒呈六角纤锌矿结构,具有沿（002）面择优生长特性,Co掺杂使ZnO纳米棒的直径变细。部分Co^2＋取代了Zn^2＋进入ZnO的晶格,掺入量为2.2at%左右。Co掺杂使ZnO的禁带宽度变窄,紫外发射峰产生显著红移。     

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纳米棒的低温生长及光致发光性能

采用化学溶液沉积法在ITO导电玻璃上制备近一维ZnO纳米棒. 利用X射线衍射（XRD) 、扫描电子显微镜（SEM）和光致发光谱（PL）对样品进行表征,研究了不同Zn2+摩尔浓度和不同生长时间对样品的结构、形貌和光致发光性能的影响. 结果表明,所制备的ZnO纳米棒为纤锌矿结构并沿c轴择优取向生长. 另外,随着Zn2+摩尔浓度的增加,纳米棒的直径增大. 当Zn2+摩尔浓度为0.1M时,ZnO纳米棒的直径和长度都随生长时间的增加而增加. PL测试表明,样品均具有良好的发光性能,并且ZnO纳米棒的结晶质量随着Zn2+摩尔浓度和生长时间的增加均有所提高.     

多种ZnO纳米结构和ZnO/ZnS核壳结构的制备

以Zn(NO3)2.6H2O和CO(NH2)2为原料,采用均匀沉淀法,制备出了棒状、花状、球状纳米氧化锌(ZnO)。将ZnO微球体分散在Na2S溶液中,通过离子替代法,成功制备了ZnO/ZnS核壳结构。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、能谱仪(EDS)等测试手段对ZnO纳米结构和ZnO/ZnS核壳结构的晶体结构和表面形貌进行了表征,初步探讨了纳米ZnO和ZnO/ZnS核壳结构的生长机理。根据测试结果得知,ZnO纳米棒呈现六方纤锌矿结构,随着Zn2+浓度逐渐增加,ZnO纳米结构形貌由单分散的棒状聚集成花状,最后演变成球形。ZnO/ZnS复合结构为内核ZnO,外面包覆一层ZnS的核壳结构。所有的纳米ZnO均具有相似的发光特点,ZnO/ZnS核壳结构的发光性能有了很大的改善。     

ZnO纳米棒的低温生长及光致发光性能

采用化学溶液沉积法在ITO导电玻璃上制备近一维ZnO纳米棒.利用X射线衍射(XRD)、扫描电子显微镜(SEM)和光致发光谱(PL)对样品进行表征,研究了不同Zn2+摩尔浓度和不同生长时间对样品的结构、形貌和光致发光性能的影响.结果表明,所制备的ZnO纳米棒为纤锌矿结构并沿c轴择优取向生长.另外,随着Zn2+摩尔浓度的增加,纳米棒的直径增大.当Zn2+摩尔浓度为0.1M时,ZnO纳米棒的直径和长度都随生长时间的增加而增加.PL测试表明,样品均具有良好的发光性能,并且ZnO纳米棒的结晶质量随着Zn2+摩尔浓度和生长时间的增加均有所提高.     

图形化氧化锌阵列的制备及其场发射性能研究

为了减小场发射的屏蔽效应,采用图形化技术对氧化锌(ZnO)纳米枝阵列进行调控,并研究图形化ZnO枝阵列的性能。首先采用光刻法在ITO导电玻璃上制备图形化ZnO种子层,再用电沉积法在图形化种子层上生长ZnO纳米枝阵列。利用扫描电子显微镜(SEM)、X射线衍射(XRD)研究所制备的图形化ZnO阵列形貌、结构等,并测试其场发射性能。研究结果表明,制备的图形化ZnO纳米枝是圆阵列,直径为330μm左右,纳米ZnO主干平均直径为400~500nm,发现主干上有一些精细的类似锥状的纳米量级微细枝结构,并且具有良好的场发射性能,开启场强为2.15V/μm,场增强因子为16 109。该图形化生长ZnO阵列阴极的方法是一种能较好改善材料场发射性能的方法,在场发射应用领域表现出较好的前景。     

ZnO纳米棒薄膜光学性能的系统研究

采用简化的种子层制备工艺在ITO基底上制备了ZnO种子层,并使用化学溶液沉积法制备了高度取向的ZnO纳米棒阵列。采用XRD和SEM对ZnO纳米棒的结构和形貌进行表征,并对样品的光学性能进行了测试。测试结果表明,所制备的ZnO纳米棒为c轴择优取向的六角纤锌矿结构,直径为66~122nm可控,且排列紧密,形貌规整。光学性能测试结果表明,吸收光谱在375nm附近表现出强烈的紫外吸收边是由于禁带边吸收引起的;反射光谱具有一定的周期振荡性,可用于薄膜厚度的估算;光致发光谱在378nm附近有很强的紫外发射峰;增大生长液浓度和高温退火可降低缺陷发光,改善结晶质量。     

RF磁控溅射和氮化法制备GaN纳米棒和纳米颗粒

利用射频磁控溅射法分别溅射ZnO中间层和Ga2O3薄膜到Si（111）衬底上，然后ZnO／Ga2O3薄膜在管式石英炉中常压下通氨气进行氨化，高温下ZnO在氨气气氛中被还原生成Zn而升华，而在不同的氨化时间下Ga2O3和氨气反应合成出GaN纳米棒和纳米颗粒。X射线衍射（XRD）测量结果表明，利用该方法制备GaN纳米棒和颗粒具有沿c轴择优取向生长的六方纤锌矿结构。利用扫描电子显微镜（SEM）、透射电子显微镜（TEM）、傅里叶红外透射谱（FTIR）及选区电子衍射（SAED）观测和分析了样品的形貌、成分和晶格结构。研究分析了此种方法合成GaN纳米结构的反应机制。     

沉积温度对纳米ZnO薄膜的结构和光电性能的影响

采用阴极电沉积的方法,用ZnCl2的二甲基亚砜溶液做电解液,在导电玻璃上制备了纳米ZnO薄膜.研究了沉积温度对薄膜结构特性和光电性能的影响.XRD分析表明,ZnO薄膜为纤锌矿结构,电解液温度的升高能促进纳米ZnO薄膜的(002)面(c轴)择优取向的程度.随着电解液温度的升高,薄膜的禁带宽度和面电阻减小.光学测试表明样品的透射率可高达80%以上,电学测试表明样品的面电阻值最小可达7.57×104 Ω/□.AFM显示电解液温度对ZnO晶粒形貌及晶粒大小的影响很大.     

生长时间对氧化锌纳米杆形貌的影响

采用旋涂法在洗净的玻璃衬底上制备了醋酸锌薄膜,并进一步在空气中退火获得了氧化锌(ZnO)薄膜,X射线衍射分析显示退火后获得的ZnO薄膜具有c轴(002)择优取向生长特性.通过水热法以ZnO薄膜为种子层,生长了ZnO纳米杆阵列.研究了在相同的ZnO种子层、前驱液浓度和生长温度条件下,不同生长时间对ZnO纳米杆形貌的影响.扫描电子显微镜照片显示,随着生长时间的增加,ZnO纳米杆阵列的生长具有阶段性规律,并且在经过52h生长后得到了顶端中心被溶解的ZnO纳米管.分析认为该现象和前驱液中Zn2+离子和OH-离子的浓度变化有关,同时也和ZnO的非极性结构有关.     

Electrical properties of templateless electrodeposited ZnO nanowires

Electrochemical deposition allows the preparation of ZnO nanostructures with precisely controlled morphology and properties, by finely tuning the process parameters. ZnO nanowires were deposited onto gold substrates by electrodeposition from a low concentration zinc nitrate bath. Photolithography was employed for patterning interdigitated electrode systems onto silicon/silicon dioxide substrates and ZnO electrodeposition lead to wires connected to each other by bridging neighboring interdigits allowing electronic transport characterization. Optical measurements, i.e. reflection and photoluminescence spectroscopy, were performed and the results were correlated to electronic transport data. We found that we deal with a system for which one can apply a model of space charge limited currents with different traps energy distribution as a consequence of electrodeposition rate. Current versus temperature measurements show different behavior for lower and higher range of temperatures. Such nanowires, fabricated and contacted in a straightforward way, allow a wide area of applications ranging from conductometric bio- or chemo-sensors to optoelectronic devices.     

Effect of pH on the properties of electrochemically prepared ZnO thin films

Zinc Oxide (ZnO) thin films have been electrochemically deposited on fluorine doped tin oxide (FTO) coated glass substrates from an aqueous electrolyte. Deposition potential −0.96 V was optimized by cyclic voltammetry experiment for slow scan rate 5 mV/s with moderate agitation of electrolyte. The effect of pH on the electrodeposition of ZnO is studied by cyclic voltammetry, X-ray diffraction (XRD), scanning electron microscopy (SEM), optical spectroscopy and photoelectrochemical I-t transient characteristics. It is revealed that the pH of the electrolyte has significant influence on the surface morphology and structural properties. Highly crystalline ZnO layers with hexagonal crystal structure deposited for all pH of the solutions. A systematic shift observed in the reflections (002) and (101) is correlated with an effective tensile strain developed in the crystal lattice. A remarkable improvement in the crystallinity was noticed in the as-deposited ZnO samples with increasing pH and upon heat treatment. Optical direct band gap ~ 3.26–3.33 eV and transmittance ~70 −80% was measured by optical spectroscopy. PL measurement showed the band edge emission at 375–382 nm and a visible light emission at 410–550 nm. The intensities of emission peaks are found to be affected by the pH of bath. The compact, densely packed and well adherent thin films of ZnO electrodeposited in zinc nitrate bath for pH 2.0, 3.5 and 6.0. The surface morphology has been changed from granular to disc shaped and finally a large hexagonal sheets were obtained with an increase in the pH of bath. Nearly stoichiometric ZnO thin films are electrodeposited at −0.96 V versus Ag/AgCl reference electrode for pH 6.0. The photoelectrochemical (PEC) measurement (I-t transient curve) shows the enhancement in photocurrent with increasing the pH of zinc nitrate solution. After heat treatment the photocurrent is increased by 54%, 98% and 130% in the samples deposited from 2.0, 3.5 and 6.0 pH of the bath. I-V measurements were further confirmed the current enhancement in all samples after heat treatment.     

镀膜光纤传感器氧化锌压电层薄膜沉积的研究

主要研究镀膜光纤传感器。首先介绍了氧化锌镀膜光纤的几何结构，分析了此几何结构压电声光振荡的基本原理，给出了光纤声光相位调制器的等效网络模型，然后根据此模型推出了声光压电层反射系数5m并按预设参数进行了计算机模拟。在此基础上，利用Zn(NO3)2单盐水溶液体系在铜基上进行阴极电沉积直接得到氧化锌镀膜，通过讨论电沉积过程中一些主要实验条件对氧化锌镀膜性能的影响，提出了一种稳定实用、经济的电沉积配方。     

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.     

Synthesis and optical property of ZnO nano-/micro-rods

A series of zinc oxide (ZnO) nano-/micro-rods had been synthesized via solution-based routes. In the hydrothermal route, the obtained ZnO nano-/micro-rods had two topographies. In refluxing procedures, spindly ZnO nanorods were obtained in the presence of poly(vinyl-pyrrolidone) (PVP) and ellipsoid-like nanorods were obtained in the absence of PVP. The products were characterized using X-ray powder diffraction (XRD),scanning electron microscope (SEM), transmission electron microscope (TEM), and electron diffraction (ED)analysis. Room temperature photoluminescence (PL)spectra of the ZnO products demonstrated a weak UV emission and a broad visible emission for each of the sample. The growth mechanism of 1-D ZnO crystals was discussed briefly.     

Mg预处理蓝宝石衬底法制备的Zn极性ZnO外延薄膜的结构研究

通过分子束外延法在经Mg预处理的蓝宝石衬底上制备了ZnO单晶薄膜,利用高分辨透射电镜、电子全息和X射线能谱对该薄膜的结构进行了细致的研究.结果表明,在蓝宝石衬底上预沉积一层很薄的Mg层,可以生长均匀Zn极性的ZnO外延薄膜.ZnO/MgO/蓝宝石的界面非常清晰锐利,同时在界面处可以观察到大约3个原子层的MgO.预沉积的Mg薄层对随后ZnO的极性选择起了关键性作用.     

ZnO growth toward optical devices by MOVPE using N2O

Wide bandgap semiconductor zinc oxide (ZnO) layers were grown by metalorganic vapor phase epitaxy (MOVPE) using nitrous oxide (N₂O). Strong ultraviolet (UV) photoluminescence emissions with 1000 times less deep ones at room temperature were observed from ZnO layers grown on sapphire. Alow temperature (500 C)-grown buffer layer of ZnO was effective to enhance the initial nucleation process and to achieve high quality ZnO layers on it at higher growth temperatures (600–700 C). ZnO layers grown on III–V semiconductor substrates showed dominant UV luminescence in spite of low temperature growth. These results imply the abilities of high quality ZnO growth by MOVPE.