离子束溅射与射频溅射制备的ZnO薄膜的特性分析

分别采用两种不同的方法制备了ZnO薄膜.①离子束溅射法(IBD),在Si(001)衬底上制备锌膜后在氧气氛炉中退火;②射频溅射法(RF),在Si(001)衬底上制备ZnO薄膜后在氧气氛炉中退火.利用X射线衍射仪和原子力显微镜(AFM)以及电感、电容、电阻综合测试仪(LCR)对两种方法制备的ZnO薄膜的结构、形貌和导电性进行了比较研究.结果表明,离子束溅射的锌膜经热氧化后得到的ZnO薄膜生长的单向性较差,表面粗糙度较大,薄膜的电阻率也比较高.     

空气中热氧化电沉积Zn纳米晶制备一维ZnO纳米针及其生长机制与场发射效应的研究

在金属基板表面电沉积一层金属Zn纳米晶，将该纳米晶置于高温炉中，通过热氧化法成功制备了一维ZnO纳米针。研究了不同的热氧化温度因素对一维ZnO纳米针的制备及其形貌的影响。在本方法中，一维ZnO纳米针材料对应于初始电沉积层的Zn纳米晶颗粒，这与其他方法中ZnO的生长机制不同，可以认为本方法的ZnO的生长遵从自催化扩散机制。同时，研究了一维ZnO纳米针薄膜的场发射效应。     

热氧化法制备透明超疏水ZnO薄膜

高透明性的无机超疏水薄膜材料具有广阔的应用前景，采用磁控溅射法制备出表面具有纳米结构的金属Zn前驱体薄膜，并利用在低气压5Pa，温度350℃热氧化方法对其采取了处理，获得了接触角为151°，可见光透过率达80％以上的超疏水ZnO薄膜。SEM表明薄膜由100nm短棒状的ZnO堆积而成，通过XRD，IR的测量与分析，进一步讨论了沉积条件及热氧化处理对超疏水透明ZnO薄膜形成机理。     

ZnO 薄膜包装材料溅射制备工艺与阻隔性能研究

目的为了解决普通聚合物包装塑料对水、氧的阻隔能力不足,以及包装内容物货架时间短等问题,研究氧化锌(ZnO)沉积复合薄膜制备工艺与阻隔性能之间的关系,探索其应用于包装材料的可行性。方法采用射频磁控溅射技术(RF),以ZnO为靶材,在PET塑料表面沉积制备氧化锌薄膜包装材料,并详细分析射频溅射功率、沉积时间与工作气压对ZnO复合薄膜微观形貌、沉积速率以及阻隔性能的影响。结果当溅射功率为150 W,沉积时间为30 min,工作气压为0.8 Pa时,ZnO薄膜均匀且致密,阻隔能力最强,其氧气透过率(OTR)降低为1.23 m L/(m2·d),水蒸汽透过率(WVTR)降低为0.382 g/(m2·d)。与相同厚度下的PET原膜相比,所制备的ZnO高阻隔薄膜的透氧率降低了49.5倍,透湿率降低了17.6倍。结论射频溅射参数通过影响复合薄膜的微观形貌、致密程度、沉积速率以及沉积层厚度等方面对其阻隔能力会产生较大影响。     

硬质膜的研制现况与展望

硬质膜是在特殊应用环境下必须具有一定电阻率的薄膜的统称。其中不仅包括耐摩擦膜,而且包括高倍物镜中的光学膜、辐射环境下使用的电学膜。介绍了薄膜结构与性能的关系,探讨了各种使用环境对薄膜性能的影响。所涉及到的薄膜沉积工艺有:离子束沉积、离子束溅射沉积、双束溅射、离子轰击蒸发、活性反应沉积、反应溅射、反应离子镀膜、等离子体辅助化学气相沉积、电子回旋共振辅助等离子体增强化学气相沉积等镀膜工艺。     

离子束溅射法制备碳氮薄膜及其结构表征

采用离子束溅射沉积技术,对不同氮离子束能量情况下制备的氮化碳薄膜,进行了拉曼(Raman)和红外光谱(FT-IR)分析,并采用透射电子显微镜(TEM)分析其表面形貌,研究所制备薄膜的化学组成和键合结构。结果显示:随着氮离子束能量增大,氮碳薄膜的沉积速率减小,薄膜结构中sp2含量增大,薄膜有序度增加,另外薄膜结构的团簇尺寸大幅下降,团簇趋于均匀分布。     

磁控溅射工艺参数对涤纶机织物基纳米金属薄膜抗静电性能的影响

在室温条件下采用磁控溅射技术在涤纶机织物表面沉积金属薄膜,利用扫描电镜(SEM)和原子力显微镜(AFM)观察纳米金属薄膜的表面形貌,通过分别改变磁控溅射工艺参数溅射时间、溅射功率和气体压强,研究其对试样抗静电性能的影响。实验结果表明,溅射时间和溅射功率对镀金属薄膜试样的抗静电性能均影响较大,而气体压强影响相对较小。溅射时间40min、溅射功率120W、气体压强1.6Pa工艺条件下,镀Cu膜试样的抗静电性能最好;溅射时间40min、溅射功率120W、气体压强1Pa或1.6Pa工艺条件下,镀Ag膜试样的抗静电性能最好,而且镀Ag比镀Cu薄膜试样的抗静电性能更优异。     

工艺参数对离子束溅射ZnO∶Al薄膜结构与性能的影响

以ZnO(掺杂2%Al2O3)陶瓷靶作为靶材,采用离子束溅射技术在BK7玻璃基底上制备AZO透明导电薄膜。研究不同工艺参数对ZnO∶Al(AZO)薄膜结构与光电性能的影响。结果表明,不同等离子体能量下制备的AZO薄膜均出现ZnO(002)特征衍射峰,具有纤锌矿结构且c轴择优取向;AZO薄膜的结晶质量和性能对基底温度有较强的依赖性,只有在适当的基底温度下,可改善结晶程度且利于颗粒的生长,呈现较低的电阻率;不同厚度的AZO薄膜均出现较强的ZnO(002)特征衍射峰且随着厚度的增加,ZnO(110)峰强度不断加强,相应晶粒尺寸变大,但缺陷也随之增多;同时得出利用离子束溅射方法制备AZO薄膜的最佳工艺为:等离子体能量为1.3 keV、基底温度200℃和沉积厚度为420 nm,该参数下制备的薄膜结晶程度较高、生长的颗粒较大,相应薄膜的电阻率较低且薄膜透射率在可见光区均达到80%以上。     

衬底离子束表面氮化对ZnO薄膜性质的影响

采用射频磁控溅射法在抛光硅片上沉积了一系列ZnO薄膜样品.通过对薄膜样品X射线衍射谱的分析、原子力显微图的观察、吸收光谱和荧光光谱的研究,发现Si衬底的离子束表面氮化对ZnO薄膜的晶体结构、表面形貌和光学性质有重要影响.在衬底温度为200℃、高纯氩氧比例为3:1、压强为1.5Pa的条件下,在经离子束表面氮化预处理的Si衬底上溅射沉积的ZnO薄膜,经450℃真空退火,成为高(0002)晶面取向的ZnO薄膜,并具有良好的光学性质.     

AZO晶种层对ZnO纳米线生长及紫外光电导性能的影响

采用溶液化学法实现了在Zn(NO3)2/C6H12N4混合溶液中ZnO纳米线在AZO薄膜修饰过衬底上生长。AZO薄膜由射频磁控溅射法制备,通过溅射时间和基底温度的变化改变薄膜形态,重点研究了不同薄膜形态对ZnO纳米线形貌和结构的影响,最终在溅射2h、基底温度250℃晶种上得到垂直于衬底、高度平行取向的ZnO纳米线阵列。在此基础上研究了不同形貌ZnO纳米线阵列的紫外光电导性能差异。结果表明,垂直生长的纳米线较倒伏纳米线紫外响应迅速,分析认为是紫外光照下曝光面积不同造成的。     

Influence of In doping on electro-optical properties of ZnO films

Thin metallic films of Zn and In/Zn were deposited onto glass substrates by thermal evaporation under vacuum. The metallic films were submitted to a thermal oxidation in air, at 623 K, for different oxidation times (30–90 min), in order to be oxidized. Structural and morphological analyses (X-ray diffraction, transmission electron microscopy and scanning electron microscopy) revealed that the obtained undoped and In-doped ZnO thin films possess a polycrystalline structure. Transmission spectra were recorded in spectral domain from 280 to 1400 nm. The influence of In doping and oxidation parameters as well, on the optical parameters (transmittance, optical bandgap, Urbach energy) were analysed. It was clearly evidenced that by In doping, the optical properties of ZnO films were improved. The temperature dependence of electrical conductivity was studied using surface-type cells with Ag electrodes. The obtained results indicate that In-doped ZnO films exhibit an enhancement of electrical conductivity with few orders of magnitude when compared with non-doped ones.     

On the structural and electrical characteristics of zinc oxide thin films

ZnO thin films with thickness d = 100 nm were deposited by radio frequency magnetron sputtering onto glass substrate from different targets. The structural analyses of the films indicate they are polycrystalline and have a wurtzite (hexagonal) structure. Crystallites are preferentially oriented with (002) plane parallel to the substrate surface and the samples have low values for surface roughness, between 1.7 nm and 2.7 nm. The mechanism of electrical conduction in the studied films is strongly influenced by this polycrystalline structure and we used Van der Pauw method to analyze these properties. Electrical studies indicate that the ZnO thin films are n-type. For the cooling process, thermal activation energy of electrical conduction of the samples can vary from 1.22 eV to 1.07 eV (for the ZnO layer obtained from for metallic Zn target) and from 0.90 eV to 0.63 eV (for the ZnO layer obtained from ZnO target), respectively. The influence of deposition arrangement and oxidation conditions on the structural and electrical properties of the ZnO films was investigated in detail.     

Microstructure, wettability and optical characteristics of ZnO/In2O3 thin films

Zinc oxide (ZnO) thin films were prepared using thermal oxidation of zinc metallic films deposited by vacuum evaporation. The structure of the as-obtained ZnO films was investigated by X-ray diffraction technique and atomic force microscopy. Investigations revealed that ZnO thin films were polycrystalline and have a hexagonal (wurtzit) structure. The structural parameters depend on the oxidation conditions. The wettability of the films was studied and was observed that under UV-irradiation the ZnO films become super-hydrophilic. Optical properties of the films were investigated and it was observed that, in visible domain, optical transmittance ranged between 85 and 95% and optical reflectance is less 15%.     

Structural and optical characterization of Al-doped ZnO films prepared by thermal oxidation of evaporated Zn/Al multilayered films

Aluminum-doped zinc oxide (ZnO:Al) thin films (t = 68–138 nm) were prepared by thermal oxidation in air flow, at 720 K, of the multilayered metallic Zn/Al thin stacks deposited in vacuum onto glass substrates by physical vapor deposition. The effect of Al content (3.7–8.2 at.%) on the structural (crystallinity, texture, stress, surface morphology) and optical (transmittance, absorbance, energy band gap) characteristics of doped ZnO thin films was investigated. The X-ray diffraction spectra revealed that the Al-doped ZnO films have a hexagonal (wurtzite) structure with preferential orientation with c-axis perpendicular to the substrate surface. A tensile residual stress increasing with Al content was observed. The films showed a high transmittance (about 90%) in the visible and NIR regions. The optical band gap value was found to decrease with Al content from 3.22 eV to 3.18 eV. The results are discussed in correlation with structural characteristics and Al content in the films.     

Influence of the substrate nature on the properties of ZnO thin films

Zinc metallic films, deposited onto different substrates, were submitted to a thermal oxidation process, in air, in order to obtain ZnO thin films. X-ray diffraction patterns revealed that as-obtained ZnO thin films were polycrystalline and have a wurtzite (hexagonal) structure. The temperature dependences of the electrical conductivity during some heating/cooling cycles were studied and the conduction mechanism was interpreted in terms of Seto model. The sensitivity of ZnO thin films, at five gases, was investigated and it was established that ethanol is the test gas that produces the most significant changes in the electrical resistance of all the studied films. Some correlations between the oxidation temperature and the substrate nature and the parameters which characterize the structural and electrical properties of ZnO thin films have been established.     

Thin polycrystalline zinc oxide films obtained by oxidation of metallic zinc films

Thin polycrystalline ZnO films were obtained by thermal oxidation of metallic Zn films, thermally deposited on various substrates, such as silica, sapphire and glass, in both air and pure oxygen atmospheres. The quality of the ZnO layers was asserted by Hall effect, cathodoluminescence and atomic force microscopy measurements. Electron concentration of 7.32×10¹² cm⁻³ and mobility of 14.2 cm²/V s with root mean square roughness of 30 nm were obtained for the 900 °C annealed ZnO films in oxygen. Room temperature cathodoluminescence spectra consisted of a narrow near band edge luminescence band and a broad defect-related green band with peak positions at 380 and 500 nm, respectively. ZnO film luminescence properties improved dramatically with the increase of annealing temperature and decrease of O₂ pressure.     

Investigation of the substrate effect for Zr doped ZnO thin film deposition by thermionic vacuum arc technique

ZnO is a fundamental wide band gap semiconductor. Especially, doped elements change the optical properties of the ZnO thin film, drastically. Doped ZnO semiconductor is a promising materials for the transparent conductive oxide layer. Especially, Zr doped ZnO is a potential material for the high performance TCO. In this paper, ZnO semiconductors were doped with Zr element and microstructural, surface and optical properties of the Zr doped ZnO thin films were investigated. Zr doped ZnO thin films were deposited thermionic vacuum arc (TVA) technique. TVA is a rapid and high vacuum deposition method. A glass, polyethylene terephthalate and Si wafer (111) were used as a substrate material. Zr doped ZnO thin films deposited by TVA technique and their substrate effect investigated. As a results, deposited thin films has a high transparency. The crystal orientation of the films are in polycrystal formation. Especially, substrate crystal orientation strongly change the crystal formation of the films. Substrate crystal structure can change the optical band gap, microstructural properties and deposited layer formation. According to the atomic force microscopy and field emission scanning electron microscopy measurements, all deposited layer shows homogeneous, compact and low roughness. The band values of the deposited thin film were approximately found as to be 3.1–3.4 eV. According to the results, Zr elements created more optical defect and shifted to the band gap value towards to blue region.     

Orientation enhancement of polycrystalline ZnO thin films through thermal oxidation of electrodeposited zinc metal

The polycrystalline ZnO thin films with (002) orientation enhancement were prepared by annealing of electrodeposited metallic Zn films from the ethylene glycol solution of zinc acetate without using any catalyst and template. The morphologies of the thin films were evolved from the nanoplate to the nanocolumn structures with increasing of annealing temperature from 100 °C to 500 °C. SEM and XRD studies indicated that the ZnO nanocolumns were enhanced in the (002) orientation along their length direction. The UV-vis absorption spectra of the ZnO films obtained by annealing at 300 °C and 500 °C were carried out and their band gaps were 3.18 eV and 3.20 eV, respectively. A possible growth mechanism of the ZnO nanostructures responsible for the morphologies and orientation evolution was discussed.     

Zinc oxide nanostructures: epitaxially growing from hexagonal zinc nanostructures

The epitaxial growth of ZnO nanosheets and nanoneedles from a Zn/ZnO core/shell structure is verified by an experiment in which the ZnO nanoneedles and nanosheets are synthesized in air within an ultra-low temperature range from?250 to 400?°C by thermal oxidation of Zn films made up of hexagonal nanodiscs or nanoprisms. The hexagonal Zn structures are oxidized to form a Zn/ZnO core/shell structure with an epitaxial relationship; ZnO nanoneedles and nanosheets are found to grow epitaxially from the ZnO shell, along sixfold symmetric [Formula: see text] directions, showing the same lattice orientation as the Zn core. The stability difference among different facets of hexagonal Zn crystal structures plays a key role in the formation of ZnO nanosheets, nanoneedles and the Zn/ZnO core/shell structure, as well as ZnO hollow structures. A vapor-solid mechanism is suggested to explain the epitaxial growth process of the ZnO products. Photoluminescence properties of the ZnO nanostructures are also explored.     

Annealing and oxidation mechanism of evaporated zinc thin films from zinc oxide powder

Zinc oxide (ZnO) thin films were deposited by thermal evaporation of a high quality ZnO powder; the obtained films were then oxidized in the air. We have systematically investigated the influence of annealing temperature ranged from 100 to 400 °C on the films composition and structural and optical properties by using Rutherford Back Scattering (RBS) analysis, X-ray Diffraction (XRD) and UV-Visible transmission respectively. The as grown films exhibit a hexagonal single phase of Zn with no preferential orientation and contain 28% oxygen. With an increase in the annealing temperature the oxygen content is enhanced to the detriment of Zn; samples were totally oxidized at 300 °C and the films are converted to stoichiometric ZnO material. However, in situ XRD pattern analysis shows that the oxidation starts at 250 °C. From the XRD results of annealed Zn samples under an electrical field we inferred that the oxidation mechanism is achieved by the ionization of oxygen atom at the film surface and subsequently followed by the diffusion of the produced ions in the film network.