偏压对磁控溅射ZnO薄膜的成核机制及表面形貌演化动力学的影响

利用反应射频磁控溅射技术,通过对基体施加负偏压溅射ZnO薄膜,探讨了固定偏压下ZnO薄膜的表面形貌随沉积时间的演化以及不同偏压对ZnO薄膜表面形貌的影响. 研究结果表明,在-100V的偏压下,随着沉积时间的增加,ZnO薄膜的表面岛尺寸不断减小,密度逐渐变大. ZnO在基片表面成核过程中的本征缺陷成核阶段和轰击缺陷成核阶段的生长指数分别为(0.45±0.03)和(0.22±0.04),低速率成核过程基本消失;随着偏压增大,表面岛的尺寸变大,表面起伏增加. 偏压不但可以改变ZnO薄膜的成核和生长过程,而且影响薄膜的晶体取向.     

基于PEG修饰的ZnO量子点光学特性研究

采用溶胶-凝胶法制备了ZnO量子点, 并采用有机高分子试剂PEG(聚乙二醇, M_w=2000)对其表面进行修饰。借助X射线衍射分析、傅立叶红外光谱、光致发光谱和透射显微镜等测试方法, 研究了PEG表面修饰对ZnO量子点结构和光学性能的影响规律。研究表明, 混合加入的PEG聚合物能够成功地包覆在ZnO量子点表面, 但没有改变量子点的晶体结构, 经PEG表面修饰后的ZnO量子点尺寸变小, 稳定性增强, 分散更均匀。同时经PEG修饰的ZnO量子点在400~500 nm波长区域缺陷态发射峰明显减弱, 表明采用PEG来改善ZnO量子点表面缺陷结构具有良好效果。     

多组分掺杂ZnO薄膜的微观结构及电学性能研究

采用射频磁控溅射法在Si(111)衬底上制备多组分掺杂ZnO薄膜,研究了衬底温度和氧分压对Bi、Cr、Sb、Mn和Co掺杂ZnO薄膜的晶体结构、表面形貌及电学性能的影响。结果表明:随着衬底温度的升高,ZnO(002)衍射峰相对强度先增强后减弱;薄膜表面粗糙度先减小后增大。随着氧分压的增大,ZnO的(101)、(102)和(103)衍射峰消失,薄膜呈优异的(002)择优取向生长。在衬底温度为300℃、氧分压为50%时,Bi、Cr、Sb、Mn和Co所引起的缺陷和氧过剩引起的本征缺陷,共同形成受主态的复合缺陷,导致晶界势垒激增。此时,薄膜有最优化的压敏电压、非线性常数和漏电流,分别达到7.05V、20.83和0.58μA/mm~2。     

TiO_2/ZnO/凹土复合材料的制备表征及紫外线屏蔽性能的研究

利用纳米二氧化钛(TiO_2)和纳米氧化锌(ZnO)屏蔽不同波长紫外线的各自特性,通过在凹土(ATP)表面负载TiO_2和ZnO来获得高效紫外线屏蔽材料,同时减少TiO_2和ZnO的团聚。并通过XRD、TEM、HRTEM、TG/DSC和Lamda 950UV-Vis等测试手段对所制备的TiO_2/ZnO/ATP复合材料进行表征。研究了煅烧温度对复合材料紫外屏蔽性能的影响。结果表明:TiO_2和ZnO均匀的负载在ATP表面;当煅烧温度为500℃时,所得的TiO_2/ZnO/ATP复合材料具有优异的中、长波广谱紫外屏蔽性能。     

氟化镧铈抛光粉的焙烧制备及抛光性能研究

采用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、原子发射光谱仪(AES)等测试技术对氟化镧铈抛光粉产物进行理化性能表征,通过无机晶体结构数据库计算产物的空间结构,用接触角测量仪、表面缺陷检测仪测定了抛光粉体的润湿性能及抛光性能。结果表明,产物均为类球状——400,500,600,700,750℃焙烧温度下得到二氧化铈(CeO₂)和氟化镧(LaF₃)的混合产物(CeO₂+LaF₃);800,850,900,950,1 000,1 050℃焙烧温度下,产物为二氧化铈(CeO₂)和氟氧化镧(LaOF)的混合抛光产物(CeO₂+LaOF),通过计算获得不同晶型的抛光产物的XRD图及其空间结构。用接触角测量仪获得500,850,1 000℃焙烧温度下的产物的润湿性能,用表面缺陷检测仪对500,850,1 000℃焙烧温度下的产物对玻璃表面进行抛光,发现温度为850℃的抛光效果最好。     

氧化锌超疏水薄膜的制备及其耐久性

为了提高氧化锌(ZnO)纳米疏水膜层在实际应用中的耐久性能,采用水热法在铝基底表面制备出微纳米结构的ZnO超疏水薄膜,利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和接触角测量仪对所得ZnO薄膜的成分、微观结构及润湿性能进行分析;利用UMT摩擦磨损试验机对薄膜的摩擦性能和机械疏水耐久度进行研究;并用CHI660E电化学工作站对超疏水试样在海水中的耐腐蚀性能进行测量分析。结果表明:制备的微纳米结构ZnO薄膜具有超疏水性,在未经低表面能物质改性的情况下,对水的静态接触角高达152°,滚动角仅为2°;摩擦磨损测试表明该薄膜在经过2 400磨损周期后仍能保持较高的静态接触角;电化学阻抗谱和Tafel曲线测试表明,该薄膜的确降低了铝在海水中的腐蚀速率,缓蚀率高达93.8%。     

从自然到仿生的超疏水表面的微观结构

利用体视显微镜、扫描电子显微镜(SEM)、接触角测量仪对蝴蝶翅膀和蝉翼表面的微细结构及疏水性能进行研究发现:蝴蝶翅膀表面的微米级孔穴和蝉翼表面的纳米阶层柱状结构,是其表面具有超疏水特性的根本原因.受此启发,用激光直写法和软刻蚀法制备出微米级周期排列的方柱、方孔微结构,测量其表面静态接触角分别为151.4°和121.7°.实验结果表明,周期排列的方柱和方孔微结构增强了固体表面的疏水性,且微结构的形态对润湿性能有很大的影响.用经典润湿理论对实验结果进行理论分析发现,Cassie理论与Wenzel理论分别适用于不同程度润湿性能的疏水微结构表面,且微结构的参数影响其表面的润湿性能.     

聚乙二醇修饰对P3HT/ZnO复合膜形貌和光学性能的影响

首先选用聚乙二醇(PEG)对水热法合成的粒径约200nm的ZnO球进行表面钝化,考察了PEG分子量、用量对ZnO薄膜形貌及光学性能的影响和PEG的能级结构;然后采用聚3-己基噻吩(P3HT)和最优参数PEG修饰前、后的ZnO纳米球共混旋涂来制备P3HT/ZnO复合膜,利用原子力显微镜、紫外-可见分光光度计、荧光光谱分析仪考察PEG钝化修饰对复合膜形貌及光学性能的影响。结果表明,采用相对分子质量为6 000、用量为5%(质量分数)的PEG修饰ZnO时,制备的ZnO薄膜均一性最好;PEG修饰的ZnO与P3HT具有良好的能级匹配性;P3HT与PEG修饰后的ZnO形成的复合膜表面规整且缺陷较少,而且在可见光区的光吸收作用增强,荧光猝灭现象加剧,表明PEG修饰增加了ZnO和P3HT的接触面积,促进了界面间的电荷转移。     

反应源温度对ZnO纳米线阵列定向性及发光性能的影响

以Au薄膜为催化剂、ZnO与碳混合粉末为反应源,采用碳热还原法在单晶Si衬底上制备了ZnO纳米线阵列.通过扫描电子显微镜( SEM)、X射线衍射仪(XRD)、荧光分光光度计对样品的表征,研究了反应源温度对ZnO纳米线阵列的定向性和光致发光性能的影响.样品在源温度920℃条件下沿(002)方向择优生长,定向性最好,温度过低不利于ZnO纳米线阵列密集生长,而温度过高导致Zn原子二次蒸发,因而也不利于纳米线阵列的定向和择优生长;样品在源温度880℃有最强的近紫外带边发射,表明温度过高和过低都不利于ZnO晶体结构的优化;由于ZnO纳米线在缺氧氛围下生长,氧空位是缺陷存在的主要形式,因此所有样品都有较强的绿光发射.温度升高导致纳米线生长速度提高而增加了氧空位缺陷数量,从而使样品绿峰强度增强并在源温度920℃时达最大值,但温度的进一步升高可导致ZnO纳米线表面Zn元素的蒸发而降低氧空位缺陷的数量,从而抑制绿峰强度.     

纳米ZnO-γ-Al_2O_3复合粉体的制备及其光催化性能

以γ-Al2O3为载体,采用均相沉淀法制备不同ZnO负载量的纳米ZnO-γ-Al2O3复合粉体。通过X射线粉末衍射(XRD)、扫描电镜(SEM)和氮气吸附对复合粉体的结构、表面形貌和比表面积进行表征。以壬基酚聚氧乙烯醚(NPE-10)为模拟污染物,对复合粉体的光催化性能进行评价。结果表明:ZnO成功负载到了γ-Al2O3表面,且负载量随着ZnO比例的增加而增加,当ZnO与γ-Al2O3质量比为2:1时,ZnO在γ-Al2O3表面形成均匀的薄膜,且这时的复合粉体催化性能最好。煅烧温度、复合物用量对其光催化性能有显著影响,300℃下煅烧所得的复合粉体,当添加量为0.3 g时,在紫外光下照射4 h后降解率可达到96%以上,重复使用6次后降解率仍可达90%以上。     

Simple, large-scale patterning of hydrophobic ZnO nanorod arrays

Here we describe a simple, versatile technique to produce large-scale arrays of highly ordered ZnO nanorods. Patterning of three distinct ZnO crystal morphologies is demonstrated through use of different ZnO seed layers. Array formation is accomplished through a simple variation on nanosphere lithography that imprints a thickness variation across a PMMA mask layer. The area of exposed seed layer is controlled through etching time in an oxygen plasma. Subsequent hydrothermal growth from the patterned seed layer produces high-quality ZnO crystals in uniform arrays. The high uniformity of the patterned array is shown to induce a high contact angle hydrophobic state even without the need for chemical modification of the ZnO surface. This technique provides a straightforward way to integrate the optical and electrical properties of high-quality ZnO nanorods with the tunable fluidic properties at the surface of well-ordered arrays.     

控制O2流量生长结状 ZnO微纳米棒及其特性研究

采用热蒸发法以锌粉和二水醋酸锌作为源材料在Si（111）衬底上制备了高密度的ZnO微纳米棒，制得的每根ZnO棒明显分为直径不同的四段．利用X射线衍射、扫描电镜、透射电镜、拉曼光谱和光致发光谱等测试手段对制备的样品进行了形貌、结构和光学性能的分析，结果表明制备的ZnO棒晶体质量良好，仅存在很少量的缺陷.通过讨论该结构的生长机理，发现O2分压对制备的ZnO微纳米棒的形貌有显著的影响，调节O2流量可控制ZnO纳米结构的形貌．     

Effects of processing parameters on ultraviolet emission of In-doped ZnO nanodisks grown by carbothermal reduction

Effects of cooling rate and oxygen partial pressure in flowing Ar on ultraviolet (UV) emission of In-doped ZnO nanodisks grown by carbothermal reduction at 1000 °C were studied. The In doping favored the growth of ZnO nanodisks instead of ZnO nanowires. Air-cooled ZnO nanodisks showed a strong green emission, while furnace cooling in conjunction with introducing O₂, around 1.0%, into flowing Ar during growth significantly enhanced the growth and UV emission of ZnO nanodisks. The causes can be attributed to the reduction of oxygen vacancies and surface defects in ZnO nanodisks. However, higher oxygen partial pressure in flowing Ar resulted in a decrease in the Zn vapor and thus suppressed the growth and UV emission of ZnO nanodisks.     

Chemical activity of oxygen atoms in the magnetron sputter-deposited ZnO films during film growth

The role of oxygen atoms in the growth of magnetron sputter-deposited ZnO films was studied in a deposition and post-deposition study in which the deposition of a several-nanometer-thick ZnO layer altered with an exposure to an O2/Ar mixed plasma, i.e., a layer-by-layer (LbL) technique. The film crystallization was promoted by suppressing the oxygen vacancy and interstitial defects by adjusting the exposure conditions of the O2/Ar plasma. These findings suggest that the chemical potential of the oxygen atom influences the film crystallization and the electronic state. The diffusion and effusion of oxygen atoms at the growing surface have an effect similar to that of thermal annealing, promoted film crystallization and the creation and the annihilation of oxygen- and zinc-related defects. The role of oxygen atoms reaching the growing film surface is discussed in terms of chemical annealing and a possible oxygen diffusion mechanism is proposed.     

籽晶辅助化学气相传输法生长ZnO单晶的特征研究

采用籽晶辅助化学气相传输法生长得到φ32mm ZnO单晶体. X射线衍射表明晶体沿c轴方向生长, 结晶质量较好: 中心部位摇摆曲线半高宽47arcsec, 边缘部分为78.4arcsec. 利用Raman谱、光致发光谱等研究了ZnO晶体退火前后的缺陷和光学性质, 表明经氧气氛退火后晶体缺陷明显减少, 晶体质量进一步提高.     

高氧空位氧化锌晶体的制备及光催化性能

利用气相沉积法,在低氧气氛下制备高缺陷的ZnO晶体。分别将样品在800℃、900℃、1000℃下通氧退火1h,对ZnO晶体做表面修饰。PL光谱实验和光催化降解亚甲基蓝实验表明ZnO晶体的氧空位、表面态和光催化活性间存在内在联系。1000℃下退火的样品表面缺陷程度多于800℃和900℃下退火样品,光催化活性也优于后两者。     

热处理气氛对ZnO透明导电膜性能的影响

采用溶胶-凝胶法、在空气、Ar气、H2气中热处理制备Al3+、F-掺杂的致密ZnO薄膜.利用XRD、SEM、分光光度计和四探针测试仪对薄膜性质进行表征.研究表明,强还原性H2气处理促进了薄膜晶界中吸附氧的解吸,减少了晶界处缺陷数目,有利于薄膜晶化程度和载流子浓度提高,所制得掺杂ZnO薄膜最低方阻为10Ω/□,在可见光范围内的达透射率在可达90%以上,性能接近ITO导电薄膜.     

Swift heavy ion induced modifications in structural,optical & magnetic properties of pure and V doped ZnO films

The effect of swift heavy ion irradiation on structural, optical and magnetic properties of pure ZnO, Zn_0.95V_0.05O and Zn_0.90V_0.10O films prepared by RF sputtering are studied. X-ray diffraction (XRD) analysis reveals no significant change in the ZnO crystal structure except a small change in intensity and peak broadening on irradiation. Raman spectra reveal the degradation of crystalline quality upon ion irradiation. Atomic force microscopy (AFM) study shows the formation of smaller sized nanostructures on ion irradiation. Photoluminescence (PL) spectra of ZnO films reveal the increase of defects such as oxygen vacancy in the films upon ion irradiation. The irradiated V doped ZnO films exhibit room temperature ferromagnetic behaviour. An increase in oxygen vacancy on ion irradiation together with V ion concentration favours enhanced ferromagnetic behaviour in irradiated V doped ZnO films.     

Chemical activity of oxygen atoms in the magnetron sputter-deposited ZnO films

The role of oxygen atoms in the growth of magnetron sputter-deposited ZnO films was studied by alternating the deposition of a several-nanometer-thick ZnO layer and an O₂/Ar mixed plasma exposure, i.e., a layer-by-layer (LbL) technique. The film crystallization was promoted by suppressing the oxygen vacancy and interstitial defects by adjusting the exposure conditions of the O₂/Ar plasma. These findings suggest that the chemical potential of the oxygen atom influences the film crystallization and the electronic state. The diffusion and effusion of oxygen atoms at the growing surface have an effect similar to that of thermal annealing, promoted film crystallization and the creation and the annihilation of oxygen- and zinc-related defects. The role of oxygen atoms reaching at the growing film surface is discussed in terms of chemical annealing and a possible oxygen diffusion mechanism is proposed.