ZnO薄膜的择优取向生长

ZnO薄膜是一种具有广泛用途的材料,近来成为了研究的热点.高度c轴择优取向是优质ZnO薄膜的重要特点.在已开发的众多生长技术中,磁控溅射、金属有机物气相沉积、脉冲激光沉积、分子束外延、电子束反应蒸镀法是生长出高度c轴择优取向优质薄膜的主要方法.介绍了这些方法及其研究进展,同时介绍了目前ZnO薄膜主要研究方面.     

电化学沉积法制备ZnO及ZnO/酞菁锌杂化薄膜

采用电化学沉积法在ITO玻璃基体上成功地制备出各种形态且均匀的ZnO及ZnO/酞菁锌薄膜.利用SEM、XRD以及UV-Vis光谱仪等分析方法对不同工艺下制备的薄膜进行了研究,结果显示所制备的纯ZnO薄膜为具有特定晶形的多晶,晶粒尺寸约为0.5～2 μ m;而ZnO/酞菁锌杂化薄膜为非晶态,染料分子与ZnO分子间的相互作用既影响了ZnO的晶体生长又改变了染料的光谱特性,形成了ZnO/酞菁锌杂化薄膜.     

反应沉积法制备c轴取向ZnO薄膜及表征

以二水合醋酸Zn为原料，采用反应沉积方法在非晶玻璃衬底上制备出了高度c轴取向、结晶良好的ZnO薄膜。研究了不同衬底温度和Zn源温度和ZnO薄膜性质的影响，探讨了不同衬底温度和Zn源温度下生长ZnO薄膜的最佳参数。本还讨论了该方法制备ZnO薄膜的沉积机制及优化条件下样品的透光特性。     

致密ZnO薄膜的电化学制备及光学性能研究

采用电化学沉积法在ITO导电玻璃上沉积1层致密的ZnO薄膜。用扫描电镜（SEM）对在不同电解液浓度、电压和时间下制备的ZnO薄膜的表面形貌作了表征,并观测了ZnO薄膜的厚度,结果表明当电解液的质量分数为1.2%,电压为1.0V,时间为60s时,制备的ZnO薄膜致密且厚度仅为120nm,利用分光光度计测得ZnO薄膜在可见光波段的透射率高于50%,为ZnO薄膜在多层光学超材料中的应用奠定了基础。     

脉冲激光沉积法室温下ZnO薄膜的制备与表征

在室温条件下,采用脉冲激光沉积技术在玻璃衬底上生长了ZnO薄膜.对薄膜的XRD分析表明,ZnO薄膜为六方纤锌矿结构并沿c轴取向生长,且(002)衍射峰的半高峰宽仅为0.24°.薄膜沿c轴方向受到一定的张应力为1.7×108 N/m2.原子力显微镜分析表明薄膜表面较为平整,平均粗糙度约为6.5 nm,晶粒尺寸约为50 nm.此外,透射光谱分析表明薄膜的禁带宽度为3.25 eV,与ZnO体材料的禁带宽度3.30 eV基本相同.     

电沉积纳米ZnO薄膜

在硝酸锌溶液中电沉积ZnO，通过正交试验方法研究槽液浓度、pH值以及电流密度对纳米ZnO薄膜电沉积的作用。用XRD分析了纳米ZnO的组织、结构与成分，SEM获得了纳米ZnO的表面形貌。     

恒电位电化学沉积Fe-Pt-B合金薄膜的研究

Fe-Pt合金薄膜作为最具有发展潜力的高密度磁记录材料而成为研究的热点．通过循环伏安法，得到了Fe-Pt-B合金薄膜最佳沉积电位。在优化条件下，采用电化学沉积法制备了Fe-Pt-B合金薄膜。利用X荧光光谱仪（EDX）、振动样品磁强计（VSM）和透射扫描电镜（SEM）对薄膜的组成、磁性能和形貌进行了初步研究．结果表明Fe-Pt合金薄膜中B的掺入可以增强薄膜的结晶度．     

纳米晶ZnO薄膜的电化学沉积及其光电化学性能研究

以Zn(NO3)2和曙红的混合溶液为沉积液,采用阴极电化学沉积法在ITO导电玻璃上制备了纳米多孔ZnO/曙红复合膜.该复合膜中的曙红用KOH溶液溶解脱附后得到晶粒尺寸为10～20nm的ZnO纳米多孔薄膜.XRD结果表明该薄膜为ZnO六方纤锌矿结构,EDS表明薄膜中的主要成份为Zn和O,未检测到其他杂质成分.以该薄膜为光阳极制作了太阳能电池原型器件,其开路电压为0.68V,短路电流为0.79 mA/cm2,总光电转换效率为0.26%..     

衬底和O2/Ar气体比例对ZnO薄膜结构及性能的影响

采用直流磁控溅射法沉积了ZnO薄膜,以X射线衍射(XRD)、扫描电镜(SEM)、原子力显微镜等手段对薄膜的晶体结构和微观相貌进行了分析,并对薄膜的电学性能进行了考察.结果表明:所制备薄膜沿c轴高度择优,并具有较高的电阻率;ZnO薄膜的沉积速率和c轴择优度是由O2/Ar气体比例和衬底共同决定的;Au衬底上的ZnO薄膜以三维生长为主,在Al和Si衬底上出现了不同程度的薄膜二维生长;电阻率随O2/Ar气体比例的提高逐渐增加,Si衬底上薄膜的电阻率高于Al和Au衬底上的.     

脉冲激光沉积ZnO薄膜的结构和光学特性研究

采用脉冲激光，在Si（001）衬底上生长ZnO薄膜，利用X射线衍射（XRD），原子力显微镜（AFM）和光致发光光谱（PL）等测试手段研究了不同衬底温度所生长的ZnO薄膜结构特征和光学性能。研究表明：衬底温度影响ZnO薄膜结构和光学性能。在500℃～600℃沉积范围内随着温度升高，ZnO薄膜结构和光学性能提高。     

ZnO thin films epitaxially grown by electrochemical deposition method with constant current

The electrochemical deposition (ECD) method is well suited to the preparation of large area devices and has several advantages, although the deposited films have a crystallinity problem. A constant current deposition method was employed for preparation of ZnO thin films in this study, because it was expected that the growth rate of the films could be controlled by means of the current density. The intensity of X-ray diffraction (XRD) peaks, and the size and shape of grains of ZnO films grown on polycrystalline Au substrates were observed to depend on the cathodic current density. On the basis of those results, deposition of ZnO on a Pt layer epitaxially grown on c-sapphire was carried out. The results of ?-scan XRD measurements showed in-plane orientation in agreement with the in-plane direction of the Pt substrate layer, which suggests that the ZnO thin film was epitaxially grown by the ECD method.     

以PVA为溶剂ZnO薄膜的液相法制备及其机理研究

以聚乙稀醇(PVA)水溶液为溶剂,采用液相法制备了高度c轴取向的ZnO薄膜。采用XRD、Raman以及AFM分析了退火温度与涂层厚度对ZnO薄膜的影响。结果表明,随着退火温度的提高,ZnO薄膜的结晶度及其均方根粗糙度有所提高;同时厚度的增加使得ZnO薄膜的单一取向性减弱。其生长机理可表述为:在每一层涂层中一致或不一致的成核同时产生,通过层内与层间晶粒的聚合、联并,最后形成具有(002)取向的柱状与颗粒状并存的ZnO连续膜。     

ZnO thin films prepared by pulsed laser deposition

Zinc oxide (ZnO) thin films were deposited on soda lime glass substrates by pulsed laser deposition (PLD) in an oxygen-reactive atmosphere. The structural, optical, and electrical properties of the as-prepared thin films were studied in dependence of substrate temperature and oxygen pressure. High quality polycrystalline ZnO films with hexagonal wurtzite structure were deposited at substrate temperatures of 100 and 300 °C. The RMS roughness of the deposited oxide films was found to be in the range 2-9 nm and was only slightly dependent on substrate temperature and oxygen pressure. Electrical measurements indicated a decrease of film resistivity with the increase of substrate temperature and the decrease of oxygen pressure. The ZnO films exhibited high transmittance of 90% and their energy band gap and thickness were in the range 3.26-3.30 eV and 256-627 nm, respectively.     

Ultrasonic-assisted fabrication of superhydrophobic ZnO nanowall films

Zinc oxide-based superhydrophobic surfaces were fabricated on aluminium oxide-seeded glass substrates via sonochemical approach by varying the parameter, the sonication time duration. The fabricated structures have nanowall-like morphology with an average long axis length and thickness of \({\sim }300\) and \({\sim }40~\hbox {nm}\), respectively.  The surface roughness created by surface-modified ZnO nanowalls and the air pockets trapped within the dense nanowalls, transformed the hydrophobic glass substrates into superhydrophobic surfaces with water contact angle of \(156{^{\circ }}\) during 20 min of sonication. An independent analysis was carried out to study the growth of ZnO nanowalls over glass substrates in the absence of the aluminium oxide seed layer and sonication process. The results suggested that the synergistic effect of the aluminium oxide seed layer and sonochemical process can enable the formation of ZnO nanowall structures favourable for superhydrophobic property. A possible growth mechanism of ZnO nanowalls formation during sonication process has been discussed in detail.     

Growth of thin ZnO films by ultrasonic spray pyrolysis

We report the growth of high-quality thin ZnO films with controlled microstructure on Si(111) substrates by ultrasonic spray pyrolysis of Zn-containing solutions.     

Comparison of structural and photoluminescence properties of ZnO thin films grown by pulsed laser deposition and ultrasonic spray pyrolysis

ZnO thin films have been deposited by pulsed laser deposition (PLD) and ultrasonic spray pyrolysis (USP) method, respectively. X-ray diffraction and transmission electron microscopy characterizations indicate that ZnO film grown by PLD exhibits better crystallinity than that grown by USP. Photoluminescence spectra show that the near-band edge ultraviolet emission of film grown by PLD is narrower and shifts to higher energy, compared with that of film grown by USP. In the visible range, ZnO film grown by PLD exhibits four local level emission centered at 470 nm, 486 nm, 544 nm, and 613 nm, respectively, while the film grown by USP only presents a weak broad band emission centered at 502 nm. Hall measurement shows higher carrier density and lower hall mobility in ZnO film grown by PLD than that in film grown by USP. The higher density of intrinsic defects as well as higher crystallintiy is considered to account for the difference of photoluminescence in ZnO film grown by PLD with that in film grown by USP.     

Structure and properties of ZnSe films grown by electrochemical deposition

ZnSe films with the sphalerite structure have been grown through electrochemical deposition from alkaline solutions. The films grown at a current density of 0.05 A/cm² consist of spherical grains ranging in size from 0.5 to 1 µm. The films are p-type and range in resistivity from 1.5 × 10⁶ to 6.8 × 10⁶ Ω m. Their band gap ranges from 2.37 to 2.55 eV.     

Effect of GaN doping on ZnO films by pulsed laser deposition

The present study reveals the codoping of Ga and N into ZnO films on sapphire substrates by pulsed laser deposition (PLD) with GaN doped ZnO targets. The glow discharge mass spectroscopy (GDMS) spectra confirm the presence of Ga and N in the doped films. The XRD measurements show that for GaN concentration up to 0.8 mol%, the full width at half maximum (FWHM) is almost unchanged thereby maintaining the crystallinity of the films, while for 1 mol% the FWHM increases. The PL spectra only show the strong near band edge (NBE) emission, whereas the deep level emissions are almost undetectable, indicating that they have been considerably suppressed. Our Hall measurements indicate that all the GaN doped ZnO films are of n-type. However, as the GaN concentration is greater than 0.6 mol%, the film shows a decrease in the carrier concentration, suggesting that N acceptors are not sufficient to compensate the native donor defects.     

Highly luminescent columnar ZnO films grown directly on n-Si and p-Si substrates by low-temperature electrochemical deposition

In this study, nanocolumnar zinc oxide thin films were catalyst-free electrodeposited directly on n-Si and p-Si substrates, what makes an important junction for optoelectronic devices. We demonstrate that ZnO thin films can be grown on Si at low cathodic potential by electrochemical synthesis. The scanning electron microscopy SEM showed that the ZnO thin films consist of nanocolumns with radius of about 150 nm on n-Si and 200 nm on p-Si substrates, possess uniform size distribution and fully covers surfaces. X-ray diffraction (XRD) measurements show that the films are crystalline material and are preferably grown along (0 0 2) direction. The impact of thermal annealing in the temperature range of 150-800 °C on ZnO film properties has been carried out. Low-temperature photoluminescence (PL) spectra of the as-prepared ZnO/Si samples show the extremely high intensity of the near bandgap luminescence along with the absence of visible emission. The optical quality of ZnO thin films was improved after post-deposition thermal treatment at 150 °C and 400 °C in our experiments, however, the luminescence intensity was found to decrease at higher annealing temperatures (800 °C). The obtained results indicate that electrodeposition is an efficient low-temperature technique for the growth of high-quality and crystallographically oriented ZnO thin films on n-Si and p-Si substrates for device applications.     

电化学制备Ba1-xSrxWO4薄膜的工艺研究及分析表征

采用恒电流技术直接在金属钨片上制备了白钨矿结构的Ba1-xSrxWO4晶态薄膜；讨论了电流密度、酸度、温度、电解液浓度等工艺条件对薄膜形成的影响。采用X射线衍射(XRD)分析了薄膜的晶相；扫描电镜(SEM)研究了薄膜的表面形貌；X射线光电子能谱(XPS)分析了薄膜的成分与价态。研究结果表明，通过控制上述工艺条件可以控制沉积薄膜的质量；在室温附近、较低的电流密度、pH值在12～13范围内时，能够制备出结晶良好、表面均匀的Ba1-xSrxWO4固溶体薄膜。