Ag层厚度对AZO/Ag/AZO透明导电薄膜性能的影响

在室温条件下,采用磁控溅射技术在玻璃衬底上生长了AZO/Ag/AZO多层透明导电薄膜。主要研究了Ag层厚度对多层透明导电薄膜结构和性能的影响。研究表明,AZO和Ag分别延(002)面和(111)面高度择优生长,随着Ag层厚度的增加,多层透明导电薄膜的电阻率不断降低,透过率呈现先降低再增加最后再降低的变化趋势,其中Ag层厚度为8nm的样品获得最大品质因子33.1×10^-3Ω^-1,综合性能最佳。     

Improved electrical and optical properties of ITO/Ag/ITO films by using electron beam irradiation and their application to ultraviolet light-emitting diode as highly transparent p-type electrodes

We have investigated the effect of insertion of a Ag layer in ITO film as well as electron beam irradiation to the multilayer films on the electrical and optical properties of the ITO-based multilayer deposited by magnetron sputtering method at room temperature. Inserting a very thin Ag layer between ITO layers resulted in a significant decrease in sheet resistance and increased the optical band gap of the ITO/Ag/ITO multilayer to 4.35 eV, followed by a high transparency of approximately 80% at a wavelength of 375 nm. We have also fabricated ultraviolet light-emitting diodes (LED) by using the ITO/Ag/ITO p-type electrode with/without electron beam irradiation. The results show that the UV-LEDs having ITO/Ag/ITO p-electrode with electron beam irradiation produced 19% higher optical output power due to the low absorption of light in the p-type electrode.     

AZO薄膜用于GaN基LED透明电极的性能研究

采用脉冲激光沉积法制备了Al掺杂ZnO(AZO)薄膜, 研究了不同沉积氧压下薄膜的光电性能。当沉积压强为0.1 Pa时, AZO薄膜光电性能最优。将该薄膜用于GaN基LED透明电极作为电流扩展层, 在20 mA正向电流下观察到了520 nm处很强的芯片发光峰, 但芯片工作电压较高, 约为10 V, 芯片亮度随正向电流的增大而增强。二次离子质谱测试表明, AZO薄膜与GaN层界面处两种材料导电性能的变化以及钝化层的形成是导致芯片工作电压偏高的原因。     

醋酸对绒面AZO薄膜表面织构均匀性的影响研究

以0.5%的稀盐酸中加入一定量醋酸后的溶液为腐蚀液,对利用直流磁控溅射方法制备的平面掺铝氧化锌(AZO)薄膜进行表面织构,并对加入醋酸后的AZO薄膜表面织构均匀性和反应机理进行研究。结果表明:在0.5%稀盐酸中所加醋酸量与盐酸体积比为0.5:1时,对平面AZO薄膜腐蚀45 s能获得更均匀陨石坑状绒面结构,且有较高绒度;腐蚀液中较水分子大得多的醋酸分子的空间位阻作用在一定程度上能减缓腐蚀速率,使得比加醋酸前获得的AZO薄膜绒面更均匀。     

Electrical,optical, and structural properties of thin films with tri-layers of AZO/ZnMgO/AZO grown by filtered vacuum arc deposition

Transparent conductive oxides (TCO) are indispensable as front electrode for most of thin film electronic devices such as transparent electrodes for flat panel displays, photovoltaic cells, windshield defrosters, transparent thin film transistors, and low emissivity windows. Thin films of aluminum-doped zinc oxide (AZO) have shown to be one of the most promising TCOs. In this study, three layered Al-doped ZnO (AZO)/ZnMgO/AZO heterostructures were prepared by filtered cathodic arc deposition (FCAD) on glass substrates. The objective is to find a set of parameters that will allow for improved optical and electrical properties of the films such as low resistivity, high mobility, high number of charge carriers, and high transmittance. We have investigated the effect of modifications in thickness and doping of the ZnMgO inner layer on the structural, electrical, and optical characteristics of the stacked heterostructures.     

Effect of AZO seed layer on electrochemical growth and optical properties of ZnO nanorod arrays on ITO glass

We report the structural and optical properties of ZnO nanorod arrays (NRAs) grown by an electrochemical deposition process. The ZnO NRAs were grown on indium tin oxide (ITO) coated glass substrates with a thin sputtered Al-doped ZnO (AZO) seed layer and compared with ones directly grown without the seed layer. The growth condition dependence of ZnO NRAs was investigated for various synthetic parameters. The morphology and density of the ZnO NRAs were accordingly controlled by means of zinc nitrate concentration and growth time. From photoluminescence results, the ultraviolet emission was significantly enhanced after thermal treatment. For ZnO NRAs grown on ITO glass without the seed layer, the diffuse transmittance was enhanced despite the reduction in the total transmittance, indicating a high haze value. By using a thin AZO seed layer, the well-aligned ZnO NRAs on AZO/ITO glass are controllably and reproducibly synthesized by varying the growth parameters, exhibiting a total transmittance higher than 91% in the visible wavelength range as well as good optical and crystal quality.     

Effect of Cu layer thickness on the structural, optical and electrical properties of AZO/Cu/AZO tri-layer films

Highly conducting AZO/Cu/AZO tri-layer films were successfully deposited on glass substrates by RF magnetron sputtering of Al-doped ZnO (AZO) and ion-beam sputtering of Cu at room temperature. The microstructures of the AZO/Cu/AZO multilayer films were studied using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and atomic force microscope (AFM). X-Ray diffraction measurements indicate that the AZO layers in the tri-layer films are polycrystalline with the ZnO hexagonal structure and have a preferred orientation with the c-axis perpendicular to the substrates. With the increase of Cu thickness, the crystallinity of AZO and Cu layers is simultaneously improved. When the Cu thickness increases from 3 to 13 nm, the resistivity decreases initially and then varies little, and the average transmittance shows a first increase and then decreases. The maximum figure of merit achieved is 1.94 × 10⁻² Ω⁻¹ for a Cu thickness of 8 nm with a resistivity of 7.92 × 10⁻⁵ Ω cm and an average transmittance of 84%.     

In-line deposition of organic light-emitting devices for large area applications

Light-emitting diodes based on organic semiconductors show promising features for display and lighting applications. A vertical in-line deposition technique for organic light-emitting diode (OLED) manufacturing was developed.OLED devices with electrically doped transport layers show low operating voltage, high efficiency and long lifetime. The preparation of p-i-n type devices was performed with the in-line fabrication tool resulting in highly efficient OLED with low operating voltage. The lowest operating voltage was achieved for green diodes with 2.9 V for 100 cd/m². This demonstrates that the p-i-n device concept can be applied under manufacturing conditions. In-line manufactured highly efficient red, green and blue OLED are presented.One important aspect for fabrication cost is the used ground contact, which is commonly made by indium tin oxide (ITO). For low cost fabrication an alternative for ITO has to be used. In this work, ITO was replaced by aluminium doped zinc oxide (ZAO). The results are comparable to OLEDs using ITO as transparent conductive oxide.     

介质/金属/介质多层透明导电薄膜研究进展

综述了介质/金属/介质(dielectric/metal/dielectric,D/M/D)多层透明导电膜材料的特点、制备方法、研究进展与应用现状,重点比较讨论了ITO/Ag/ITO、ZnS/Ag/ZnS的膜系结构、光电性能、化学稳定性、热稳定性等特点,以及与国内外的研究差距.ITO/Ag/ITO、ZnS/Ag/ZnS是目前光电性能最好,且无需引入过渡层的两种D/M/D膜系,但有关其热稳定性的评价和研究存在不同的观点.用资源丰富、价格便宜、无毒的掺铝氧化锌(ZAO)薄膜取代含有价格昂贵的贵金属铟的掺锡氧化铟(ITO)薄膜,ZAO/Ag/ZAO膜系结构的设计、薄膜制备、光电性能与IMI的对比研究是目前国内外D/M/D研究中的热点课题和D/M/D发展的主要方向.     

Improved performance of the single-layer and double-layer organic light emitting diodes by nickel oxide coated indium tin oxide anode

The electrical and optical properties of the NiO films deposited under various conditions were first characterized. An ultra-thin layer of nickel oxide (NiO) was then deposited on the indium-tin oxide (ITO) anode to enhance the hole injection in the organic light-emitting diode (OLED) devices. A very low turn-on voltage (3 V) was actually observed for the device with the ITO/NiO anode in the conventional double layer heterojunction OLEDs. The enhancement of hole injection by the ITO/NiO anode was further verified by the hole-only device and by the device with a patterned NiO layer on the ITO anode. The luminance and the current density of the single-layer OLED device were also significantly improved by using the ITO/NiO anode to enhance the hole injection. Although the luminescence efficiency was low, the reasons of low efficiency were studied and the improvement method was proposed. Our results suggest that the NiO/ITO anode is an excellent choice to enhance the hole injection in OLED devices.     

Optimization of ZnO:Al/Ag/ZnO:Al structures for ultra-thin high-performance transparent conductive electrodes

Al-doped ZnO (AZO)/Ag/AZO multilayer coatings (50-70 nm thick) were grown at room temperature on glass substrates with different silver layer thickness, from 3 to 19 nm, by using radio frequency magnetron sputtering. Thermal stability of the compositional, optical and electrical properties of the AZO/Ag/AZO structures were investigated up to 400 °C and as a function of Ag film thickness. An AZO film as thin as 20 nm is an excellent barrier to Ag diffusion. The inclusion of 9.5 nm thin silver layer within the transparent conductive oxide (TCO) material leads to a maximum enhancement of the electro-optical characteristics. The excellent measured properties of low resistance, high transmittance in the visible spectral range and thermal stability allow these ultra-thin AZO/Ag/AZO structures to compete with the 1 μm thick TCO layer currently used in thin film solar cells.     

Study of optoelectronics and microstructures on the AZO/nano-layer metals/AZO sandwich structures

In this study, growth nano-layer metals (Al, Cu, Ag) and Al-doped ZnO (AZO) thin films are deposited on glass substrates as the transparent conducting oxides (TCOs) to form AZO/nano-layer metals/AZO sandwich structures. The conductivity properties of thin films are enhanced when the average transmittance over the wavelengths 400–800 nm is maintained at higher than 80 %. A radio frequency magnetron sputtering system is used to deposit the metal layers and AZO thin films of different thickness, to form AZO/Al/AZO (ALA), AZO/Cu/AZO (ACA) and AZO/Ag/AZO (AGA) structures. X-ray diffraction and field emission scanning electron microscopy are used to analyze the crystal orientation and structural characteristic. The optical transmission and resistivity are measured by UV–VIS–NIR spectroscopy and Hall effect measurement system, respectively. The results show that when the Ag thickness is maintained at approximately 9 nm, the TCOs thin film has the lowest resistivity of 8.9 × 10^?5 Ω-cm and the highest average transmittance of 81 % over the wavelengths 400–800 nm. The crystalline Ag nano-crystal structures are observed by high-resolution transmission electron microscopy. In addition, the best figure of merit for the AZO/Ag/AZO tri-layer film is 2.7 × 10^?2 (Ω^?1), which is much larger than that for other structures.     

Structural, optical and electrical properties of AZO/Cu/AZO tri-layer films prepared by radio frequency magnetron sputtering and ion-beam sputtering

Highly conducting tri-layer films consisting of a Cu layer sandwiched between Al-doped ZnO (AZO) layers (AZO/Cu/AZO) were prepared on glass substrates at room temperature by radio frequency (RF) magnetron sputtering of AZO and ion-beam sputtering of Cu. The tri-layer films have superior photoelectric properties compared with the bi-layer films (Cu/AZO, AZO/Cu) and single AZO films. The effect of AZO thickness on the properties of the tri-layer films was discussed. The X-ray diffraction spectra show that all films are polycrystalline consisting of a Cu layer with the cubic structure and two AZO layers with the ZnO hexagonal structure having a preferred orientation of (0 0 2) along the c-axis, and the crystallite size and the surface roughness increase simultaneously with the increase of AZO thickness. When the AZO thickness increases from 20 to 100 nm, the average transmittance increases initially and then decreases. When the fixed Cu thickness is 8 nm and the optimum AZO thickness of 40 nm was found, a resistivity of 7.92 × 10⁻⁵ Ω cm and an average transmittance of 84% in the wavelength range of visible spectrum of tri-layer films have been obtained. The merit figure (F_TC) for revaluing transparent electrodes can reach to 1.94 × 10⁻² Ω⁻¹.     

Ordered ZnO/AZO/PAM nanowire arrays prepared by seed-layer-assisted electrochemical deposition

An Al-doped ZnO (AZO) seed layer is prepared on the back side of a porous alumina membrane (PAM) substrate by spin coating followed by annealing in a vacuum at 400 °C. Zinc oxide in ordered arrays mediated by a high aspect ratio and an ordered pore array of AZO/PAM is synthesized. The ZnO nanowire array is prepared via a 3-electrode electrochemical deposition process using ZnSO₄ and H₂O₂ solutions at a potential of − 1 V (versus saturated calomel electrode) and temperatures of 65 and 80 °C. The microstructure and chemical composition of the AZO seed layer and ZnO/AZO/PAM nanowire arrays are characterized by field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and energy-dispersive X-ray spectroscopy (EDS). Results indicate that the ZnO/AZO/PAM nanowire arrays were assembled in the nanochannel of the porous alumina template with diameters of 110–140 nm. The crystallinity of the ZnO nanowires depends on the AZO seed layer during the annealing process. The nucleation and growth process of ZnO/AZO/PAM nanowires are interpreted by the seed-layer-assisted growth mechanism.     

Fabrication of KTa0.65Nb0.35O3 film by pulsed laser deposition on glass substrate with various buffer layers

KTa_0.65Nb_0.35O₃ (KTN) thin films were deposited on amorphous glass substrates using a range of single buffer layers such as indium tin oxide (ITO), zinc oxide (ZnO), 3 at% Al-doped ZnO (AZO), and 3 at% Ga-doped ZnO (GZO), as well as a variety of multi-buffer layers such as SrTiO₃ (STO)/ITO, STO/ZnO, STO/AZO, and STO/GZO using a pulsed laser deposition system. All films showed a polycrystalline perovskite phase with the exception of all single buffer layers and STO/ITO multi-buffer layers. The STO buffer layer is important for crystallizing KTN films due to the similar lattice constant and same crystal structure. The optical transmittance of all films exhibited a transmittance ?90% in the wavelength range.     

Fabrication and Properties of DC Magnetron Sputtered Indium Tin Oxide on Flexible Plastic Substrate

Indium tin oxide (ITO) thin films deposited on flexible polyethylene terephthalate (PET) substrates at low temperature by DC magnetron sputtering from an In-Sn (90-10 wt pct) alloy target were studied. The correla-tion between deposition conditions and ITO property was systematically investigated and characterized. These as-deposited ITO films were used as the anode contact for flexible organic light-emitting diodes (FOLEDs). The fabricated FOLEDs with a structure of PET/ITO/NPB (50 nm)/Alq (20 nm)/Mg:Ag (100 nm) showed a maximum luminance of 2125 cd/m2 at 13 V.     

Quality enhancement of AZO thin films at various thicknesses by introducing ITO buffer layer

Due to the simultaneously superior optical transmittance and low electrical resistivity, transparent conductive electrodes play a significant role in semiconductor electronics. To enhance the electrical properties of these films, one approach is thickness increment which degrades the optical properties. However, a preferred way to optimize both electrical and optical properties of these layers is to introduce a buffer layer. In this work, the effects of buffer layer and film thickness on the structural, electrical, optical and morphological properties of AZO thin films are investigated. Al-doped zinc oxide (AZO) is prepared at various thicknesses of 100 to 300 nm on the bare and 100 nm-thick indium tin oxide (ITO) coated glass substrates by radio frequency sputtering. Results demonstrate that by introducing ITO as a buffer layer, the average values of sheet resistance and strain within the film are decreased (about 76 and 3.3 times lower than films deposited on bare glasses), respectively. Furthermore, the average transmittance of ITO/AZO bilayer is improved nearly 10% regarding single AZO thin film. This indicates that bilayer thin films show better physical properties rather than conventional monolayer thin films. As the AZO film thickness increases, the interplanar spacing, d₍₀₀₂₎, strain within the film and compressive stress of the film in the hexagonal lattice, decreases indicating the higher yield of AZO crystal. Moreover, with the growth in film thickness, carrier concentration and optical band gap (E_g) of AZO film are increased from 4.62?×?10¹⁹ to 8.21?×?10¹⁹ cm^?3 and from 3.55 to 3.62 eV, respectively due to the Burstein-Moss (BM) effect. The refractive index of AZO thin film is obtained in the range of 2.24–2.26. With the presence of ITO buffer layer, the AZO thin film exhibits a resistivity as low as 6?×?10^?4 Ω cm, a sheet resistance of 15 Ω/sq and a high figure of merit (FOM) of 1.19?×?10⁴ (Ω cm)^?1 at a film thickness of 300 nm. As a result, the quality of AZO thin films deposited on ITO buffer layer is found to be superior regarding those grown on a bare glass substrate. This study has been performed over these two substrates because of their significant usage in the organic light emitting diodes and photovoltaic applications as an enhanced carrier injecting electrodes.     

掺铝氧化锌薄膜表面织构机制的研究

采用氯化铵(NH4Cl)溶液对磁控溅射技术制备的掺铝氧化锌(AZO)薄膜进行表面织构,并对其表面织构机制进行研究.研究结果表明NH4Cl溶液优先与间隙锌、间隙铝等缺陷和晶界处的堆积铝反应,而较大的相对应力和稀疏表面有助于间隙锌、间隙铝等缺陷和堆积铝的形成.它们对NH4Cl对AZO薄膜的表面织构很关键.     

不同退火工艺对AZO膜性能的影响

掺铝氧化锌(AZO)薄膜由于其独特的光学和电学性能而倍受人们的青睐。本文采用射频磁控溅射技术,制备了综合性能优良的AZO薄膜,通过不同退火工艺处理,研究了其对AZO薄膜的组织结构、电学性能及光学性能的影响。氮气环境下的退火使得AZO膜出现了更为明显的蓝移现象,氢气环境下的退火提高了薄膜的导电性。     

Investigation of conductive and transparent Al-doped ZnO/Ag/Al-doped ZnO multilayer coatings by electron beam evaporation

Multilayer coatings consisting of thin silver layer sandwiched between layers of Al-doped ZnO (AZO) were prepared by electron beam evaporation. The optical and electrical performances of AZO/Ag/AZO multilayers were investigated. Optimization of the multilayer coatings resulted with low sheet resistance of 7.7 Ω/sq and transmittance of 85%. The influence of thickness of each layer on the optic and electrical performance was analyzed. The sheet resistance of the multilayer was reduced to 5.34 Ω/sq. and the average transmittance was improved to 90% by the thermal treatment. The coatings had satisfactory properties of low resistance, high transmittance and thermal stability.