Influence of deposition pressure on properties of ZnO: Al films fabricated by RF magnetron sputtering

Transparent conductive aluminum doped zinc oxide(ZnO:Al,AZO) films were prepared on glass substrates by rf(radio frequency) magnetron sputtering from ZnO: 3wt% Al_2O_3 ceramic target. The effect of argon gas pressure(PAr) was investigated with small variations to understand the influence on the electrical, optical and structural properties of the films. Structural examinations using X-ray diffraction(XRD) and scanning electron microscopy(SEM) showed that the ZnO:Al thin films were(002) oriented. The resistivity values were measured by four-point probe with the lowest resistivity of 5.76×10~(-4) Ω?cm(sheet resistance=9.6 Ω/sq. for a thickness=600 nm) obtained at the PAr of 0.3 Pa. The transmittance was achieved from ultravioletvisible(UV-VIS) spectrophotometer, 84% higher than that in the visible region for all AZO thin films. The properties of deposited thin films showed a significant dependence on the PAr.     

ZnO薄膜的制备及其Al掺杂工艺的初步探讨

采用MF-PECVD法制备ZnO和高透射率的ZAO薄膜,分析了影响ZnO和ZAO薄膜质量的因素。研究了透射率与衬底温度、沉积时间、锌源浓度以及A l杂质含量之间的关系,讨论了工艺参数对薄膜透射率、颜色、均匀度、附着力、成膜速率及其晶型的影响,给出了制备ZnO和ZAO薄膜的优化条件。     

沉积温度对ZnO薄膜结构形貌及光学性能的影响

以Zn(NO3)2·6H2O为前驱体,采用超声喷雾热解法在玻璃衬底上沉积了ZnO薄膜,采用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外光谱仪(UVS)等对所得ZnO薄膜进行表征,研究了沉积温度对ZnO薄膜的结构、微观形貌及光学性能的影响。结果表明,沉积温度为500℃时所制备的薄膜质量最佳,形成的是六角纤锌矿ZnO结构,且薄膜沿(002)晶面择优取向生长显著,薄膜表面光滑致密,晶粒细小均匀,尺寸在50~60nm。薄膜表现出良好的光学性能,可见光透过率可达87%。     

氩气流量对丙纶基氧化锌/铜复合膜结构及抗紫外线性能的影响

在室温条件下先用直流溅射的方式在丙纶非织造布表面沉积铜膜,再用射频磁控溅射法在铜膜表面沉积氧化锌薄膜形成层状膜,借助X射线能谱仪（EDX）、扫描电子显微镜（SEM）、原子力显微镜（AFM）和X射线衍射（XRD）观察薄膜结构,通过改变氩气流量研究其对织物紫外线透过率的影响.实验结果表明,随着氩气流量的增加,纳米薄膜颗粒先增大后缩小,紫外线透过率也先升高后降低,在氩气流量为40 mL/min时,紫外线透过率最低.     

ZnO films on transferable and low thermal resistance graphite substrate grown by ultrasonic spray pyrolysis

ZnO thin films were deposited on graphite substrates by ultrasonic spray pyrolysis method with Zn(CH 3 COO) 2 ·2H 2 O aqueous solution as precursor. The crystalline structure, morphology, and optical properties of the as-grown ZnO films were investigated systematically as a function of deposition temperature and growth time. Near-band edge ultraviolet(UV) emission was observed in room temperature photoluminescence spectra for the optimized samples, yet the usually observed defect related deep level emissions were nearly undetectable, indicating that high optical quality ZnO thin fi lms could be achieved via this ultrasonic spray pyrolysis method. Considering the features of transferable and low thermal resistance of the graphite substrates, the achievement will be of special interest for the development of high-power semiconductor devices with suffi cient power durability.     

Effect of silver growth temperature on the contacts between Ag and ZnO thin films

Highly c-axis oriented ZnO thin films were deposited on Si substrates by the pulsed laser deposition (PLD) method. At different growth temperatures, 200 nm silver films as the contact metal were deposited on the ZnO thin films. The growth temperatures have great influence on the crystal quality of Ag films. Current-voltage characteristics were measured at room temperature. The Schottky contacts between Ag and ZnO thin films were successfully obtained when silver electrodes were deposited at 150°C and 200°C. Ohmic contacts were formed while the growth temperatures were lower than 150°C or higher than 200°C. After analysis, the forming of Ag/ZnO Schottky contacts was shown to be dependent on the appearance of the p-type inversion layer at the interface between Ag and ZnO layers.     

CdO - ZnO复合薄膜的光电学特性研究

采用磁控溅射技术制备了不同原子百分比的CdO - ZnO复合薄膜,并利用X射线衍射仪、扫描电子显微镜、紫外可见近红外分光光度计、四探针电阻测试仪研究了薄膜的结构和光电学特性.研究表明:适量增加CdO掺杂量可提高薄膜在近红外区域的透射率; CdO - ZnO复合薄膜的光学带隙和电阻率随CdO含量的增加而减小,且当CdO和ZnO的原子百分比为4:1时薄膜的带隙和电阻率分别为2.09 eV和10.79×10^-3 Ω·cm.该研究结果可为制备高导电性和高透过率的薄膜提供参考.     

Effects of potential and temperature on the electrodeposited porous zinc oxide films

Porous ZnO films were prepared by electrodeposition method in zinc nitrate aqueous solution using ITO glass covered with polystyrene sphere (PS) colloidal crystal arrays as substrates. The preparation procedure includes two parts: deposition of ZnO in the interstices of the colloidal crystals and subsequent removal of the PS templates. The influences of deposition potential and temperature on the ZnO films were investigated. The ordered, uniform porous ZnO films with optical transmittance of approximately 63.6% at 600 nm could be obtained when the deposition potential and temperature were –1.1 V and 70 ℃, respectively. The optical band gap energy increased along with the absolute deposition potential and temperature, ranging from 3.33 to 3.43 eV and from 3.35 to 3.42 eV, respectively.     

铝搀杂氧化锌薄膜的结构与光电特性

ZnO:Al薄膜以其低电导率、高可见光透射率、高红外光反射率等光电特性和原料易得、低成本、无毒、易掺杂、在等离子体中稳定性好、易刻蚀等特点,在平板显示器件、太阳能电池、反射热镜、气体敏感器件、特殊功能窗口涂层等领域有着广阔的应用前景。在重点讨论ZnO:Al薄膜的组织结构、导电机制、透光机制以及搀杂和制备工艺等对ZnO:Al薄膜结构与光电特性的影响基础上,指出了ZnO:Al薄膜目前存在的问题并提出了今后研究的努力方向。     

UV-vis and photoluminescent spectra of TiO<Subscript>2</Subscript> films

TiO₂ fims have been deposited on glass substrates using DC reactive magnetron sputtering at different oxygen partial pressures from 0. 10 Pa.to 0.65 Pa. The transmittance (UV-vis) and photoluminescence (PL) spectra of the films were recorded. The results of the UV-vis spectra show that the deposition rate of the films decreased at oxygen partial pressure P(O₂)≥0.15 Pa, the band gap increased from 3.48 eV to 3.68eV for direct transition and from 3.27 eV to 3.34 eV for indirect transition with increasing the oxygen partial pressure. The PL spectra show convincingly that the transition for films was indirect, and there were some oxygen defect energy levels at the band gap of the films. With increasing the O₂ partial pressure, the defect energy levels decreased. For the films sputtered at 0.35 and 0.65 Pa there were two defect energy levels at 2.63 eV and 2.41 eV, corresponding to 0.72 eV and 0.94 eV below the conduction band for a band gap of 3.35 eV, respectively. For the films sputtered at 0.10 Pa and 0.15 Pa, there was an energy band formed between 3.12 eV and 2.06 eV, corresponding to 0.23 eV and 1.29 eV below the conduction band. ZHAO Qing-nan : Born in 1963 Funded by Natural Science Foundation of Hubei Province, China.     

Improved visible transparency of SIO<Subscript>2</Subscript>/ZNO:AL /CEO<Subscript>2</Subscript>-TIO<Subscript>2</Subscript>/SIO<Subscript>2</Subscript> multilayer films with high UV absorption and infrared reflection rate

New visible transparent, UV absorption, and high infrared reflection properties have been realized by depositing multilayer SiO₂/ZnO: Al/CeO₂-TiO₂/SiO₂ films onto glass substrates at low temperature by radio frequency magnetron sputtering. Optimum thickness of SiO₂, ZnO: Al (ZAO) and CeO₂-TiO₂ (CTO) films were designed with the aid of thin film design software. The degree of antireflection can be controlled by adjusting the thickness and refractive index. The outer SiO₂ film can diminish the interference coloring and increase the transparency; the inner SiO₂ film improves the adhesion of the coating on the glass substrate and prevents Ca²⁺, Na⁺ in the glass substrate from entering the ZAO film. The average transmittance in the visible light range increases by nearly 18%-20%, as compared to double layer ZAO/CTO films. And the films display high infrared reflection rate of above 75% in the wavelength range of 10-25 μm and good UV absorption (> 98%) properties. These systems are easy to produce on a large scale at low cost and exhibit high mechanical and chemical durability. The triple functional films with high UV absorption, antireflective and high infrared reflection rate will adapt to application in flat panel display and architectural coating glass, automotive glass, with diminishing light pollution as well as decreasing eye fatigue and increasing comfort.     

Growth and characterization of indium doped zinc oxide films sputtered from powder targets

Indium doped Zn O films were grown on quartz glass substrates by radio frequency magnetron sputtering from powder targets. Indium content in the targets varied from 1at% to 9at%. In doping on the structure, optical and electrical properties of Zn O thin films were studied. X-ray diffraction shows that all the films are hexagonal wurtzite with c-axis perpendicular to the substrates. There is a positive strain in the films and it increases with indium content. All the films show a high transmittance of 86% in the visible light region. Undoped Zn O thin film exhibits a high transmittance in the near infrared region. The transmittance of indium doped Zn O thin films decreases sharply in the near infrared region, and a cut-off wavelength can be found. The lowest resistivity of 4.3×10~(-4) Ω·cm and the highest carrier concentration of 1.86×10~(21) cm~(-3) can be obtained from Zn O thin films with an indium content of 5at% in the target.     

Preparation and Characterization of Highly Oriented ZnO Film by Ultrasonic Assisted SILAR Method

Ultrasonic Assisted SILAR method （UA-SILAR） was developed and highly oriented ZnO films were deposited on the glass substrate by this novel technique. The crystallinity and microstructure of as-deposited ZnO films were analyzed by means of XRD and SEM. Moreover, the underling deposition mechanism of ZnO films was discussed. Results show that obtained ZnO films exhibit an excellent crystallinity with the preferentioal orientation of （002） plane. The crystalline grain of films is about 40nm in size,which is supported by both the Sherrer equation and the SEM result. However, the ZnO film is composed of numerous clustered purticulates in the size of 200 to 300nm, and each particulate is the compact aggregation of smaller ZnO crystalline grains. It is .speculated that the excellent crystallinity of ZnO films may chiefly originate from the cavatition effect of the ultrasonic rinsing process.     

溶胶-凝胶法制备氧化锌薄膜

采用了溶胶-凝胶工艺在普通的玻璃载玻片上成功地制备出具有c轴择优取向性、高的可见光透光率、平整均匀的氧化锌薄膜。通过XRD、AFM以及UV光谱仪等分析,其结果表明:所制备的氧化锌薄膜具有纤锌矿型结构,表面均匀致密,薄膜晶粒尺寸大约在40~90 nm,溶胶浓度增大时,其晶粒大小呈增大的趋势。随着涂膜层数的增加,薄膜的(002)方向的取向度增加。薄膜在可见光区的光透过率>85%,在近紫外光波段透射率急剧减小,对应的禁带宽度为3.34 eV。     

Al掺杂对ZnO薄膜结构和光学性能的影响

研究了Al掺杂对采用直流磁控溅射方法制备的ZnO薄膜结构及光学性能的影响。X射线衍射结果揭示薄膜具有良好的C轴择优取向生长特性,同时,衬底温度对它们的透射谱和荧光谱有着明显影响,所有薄膜都有大于86%的可见光透过率和陡峭的本征吸收边,但ZAO薄膜的光学透过率略低。Al掺杂导致了更宽的光学带隙,光致发光光谱显示ZnO具有较强的近带本征吸收峰和深能级发射峰,但Al掺杂使得深能级发射峰降低。随着衬底温度的升高,近带边吸收峰蓝移,与光学带隙Eg变化趋势一致。     

氧化铝缓冲层对ZnO薄膜性质的影响

采用反应磁控溅射的方法在石英衬底上制备了一层AI2O3薄膜,并将其作为后续ZnO薄膜生长的缓冲层.然后,采用反应磁控溅射的方法在AI2O3缓冲层上制备了ZnO薄膜.对比研究了引入Al2O3缓冲层前后,ZnO薄膜的结构和光学特性.通过引入Al2O3缓冲层,发现ZnO薄膜样品的(002)方向X射线衍射峰的半峰宽(FWHM)明显减小,光致发光谱中与缺陷相关的可见发光峰强度明显减弱,吸收光谱中的吸收边变得更加陡峭.这些结果表明引入Al2Q3缓冲层后,ZnO薄膜的结构和光学特性得到了很大改善,为制备高质量ZnO薄膜提供了参考.     

Study on pulsed laser ablation and deposition of ZnO thin films by L-MBE

ZnO,as a wide-band gap semiconductor,has recently become a new research fo-cus in the field of ultraviolet optoelectronic semiconductors. Laser molecular beam epitaxy(L-MBE) is quite useful for the unit cell layer-by-layer epitaxial growth of zinc oxide thin films from the sintered ceramic target. The ZnO ceramic target with high purity was ablated by KrF laser pulses in an ultra high vacuum to deposit ZnO thin film during the process of L-MBE. It is found that the deposition rate of ZnO thin film by L-MBE is much lower than that by conventional pulsed laser deposition(PLD) . Based on the experimental phenomena in the ZnO thin film growth process and the thermal-controlling mechanism of the nanosecond(ns) pulsed laser abla-tion of ZnO ceramic target,the suggested effective ablating time during the pulse duration can explain the very low deposition rate of the ZnO film by L-MBE. The unique dynamic mechanism for growing ZnO thin film is analyzed. Both the high energy of the deposition species and the low growth rate of the film are really beneficial for the L-MBE growth of the ZnO thin film with high crystallinity at low temperature.     

Preparation and Properties of IrO2 Thin Films Grown by Pulsed Laser Deposition Technique

Highly conductive IrO2 thin films were prepared on Si （100） substrates by means of pulsed laser deposition technique from an iridium metal target in an oxygen ambient atmosphere. Emphasis was put on the effect of oxygen pressure and substrate temperature on the structure, morphology and resistivity of IrO2 films. It was found that the above properties were strongly dependent on the oxygen pressure and substrate temperature. At 20 Pa oxygen ambient pressure, pure polycrystalline IrO2 thin films were obtained at substrate temperature in the 300-500℃ range with the preferential growth orientation of IrO2 films changed with the substrate temperature. IrO2 films exhibited a uniform and densely packed granular morphology with an average feature size increasing with the substrate temperature. The room-temperature resistivity variations of IrO2 films correlated well with the corresponding film morphology changes. IrO2 films with the minimum resistivity of （42 ±6）μΩ·cm was obtained at 500℃.     

氧氩比和退火温度对AZO薄膜结构与性能的影响

在通氩气和不同比率氧氩混合气体的条件下,利用射频磁控溅射法在玻璃衬底上制备铝(Al)掺杂氧化锌(AZO)薄膜(溅射功率为180W,衬底温度为300℃),并对部分薄膜样品进行400℃或500℃退火处理.采用X射线衍射仪(XRD)、原子力显微镜(AFM)和分光光度计对薄膜的结构、表面形貌和光学性能进行测试研究.结果表明,制备的所有薄膜均呈现(002)晶面择优生长;与氩气溅射相比,当采用氧氩混合气体溅射时,生长的AZO薄膜晶粒尺寸显著增大;退火处理使2类薄膜的表面粗糙度都明显减小,晶粒也有所增大(7%~13%).其中,在氧氩比为1∶2的混合气体中制备的薄膜,经过500℃退火后,晶粒尺寸最大(39.4nm),薄膜表面更平整致密,在可见光区平均透过率接近最大(89.3%).     

Preparation of Indium Tin Oxide Films on Polycarbonate substrates by Radio-frequency Magnetron Sputtering

1Introduction Indiumtinoxide(ITO)isadegeneraten typesemi conductingmaterialthathaswideapplicationsinoptics andoptoelectronics,suchasflatpaneldisplaydevices,antireflectioncoatings,pilotwindows,andheterojunction solarcells.Itselectricalopticalpropertieshave…