Study on the electrical and optical properties of ITO and AZO thin film by oxygen gas flow rate

Transparent conductive oxide (TCO) thin films such as tin doped indium oxide (ITO), zinc doped indium oxide (IZO) and Al doped zinc oxide (AZO) have been widely used as transparent electrode for display. ITO and AZO thin films for display was prepared by the facing targets sputtering (FTS) system. The FTS method is called a plasma-free sputter method because the substrate is located apart from plasma. This system can deposit the thin film with low bombardment by high energetic particles in plasma such as γ-electrons, negative ions and reflected Ar atoms. ITO and AZO thin films were deposited on glass substrate at room temperature with oxygen gas flow rate and input power. And the electrical, structural and optical properties of the thin films were investigated. As a result, the resistivity of ITO, AZO thin film is 6?×?10^?4 Ω cm, 1?×?10^?3 Ω cm, respectively. And the optical transmittance of as-deposited thin films is over 80% at visible range.     

靶材密度对射频磁控溅射法制备ITO薄膜性能的影响

以不同密度的氧化锡铟（ITO））靶材为原料,采用射频磁控溅射法,在室温下沉积并经750℃退火,获得了电阻率为1．56×10^-4Ω·cm、可见光透过率为87％的ITO薄膜。对不同密度靶材制备的ITO薄膜的微观结构、电学及光学性能进行了表征与探讨。结果表明,采用射频磁控溅射法时,不同靶材密度对ITO薄膜的沉积速率、结构、电学和光学性能均无显著影响。该结果为采用低密度ITO靶材制备高品质ITO薄膜提供了一个新的思路。     

Effects of substrate temperature on electrical and optical properties ITO films deposited by r.f. magnetron sputtering

Indium tin oxide (ITO) films have been prepared by r.f. magnetron sputtering using powder target. X-ray diffraction analysis indicates that the deposited films were polycrystalline and retained a cubic bixbite structure. The ITO films deposited at low substrate temperature (T _s) exhibit a (411) preferred orientation but the films deposited at high T _s prefer a (111) orientation. The substrate temperature was found to significantly affect the electrical properties. As the T _s was increased, the conductivity of ITO films was improved due to thermally induced crystallization. The lowest resistivity (8.7?×?10^?4 Ω-cm) was obtained from ITO films deposited at 450 °C. However, optical properties of the films were somewhat deteriorated. The infrared (IR) reflectance of the film increases with increasing the substrate temperature.     

Surface modification of stainless steel bipolar plates for PEMFC (proton exchange membrane fuel cell) application

Stainless steel 316 and 304 plates were deposited with a metallic film (top layer) and a conductive oxide film (intermediate layer) by a sputtering method and an E-beam method, respectively. The conductive oxide film was formed on the stainless steel plates in the range of thickness of 200, 400, and 600 nm. The XRD patterns of the conductive oxide films showed a typical indium-tin oxide (ITO) crystalline phase. The metallic films of 100 nm thickness were subsequently formed on the surface region of the bare stainless steel plates and the stainless steel plates deposited with ITO thin film. Surface morphologies of the stainless steel bipolar plates deposited with conductive film and metallic film were observed by AFM and FE-SEM. The metallic films on the stainless steel plates represented the microstructural morphology of the fine columnar grains of 10 nm diameter and 60 nm length. The electrical resistivity and contact angle of the stainless steel bipolar plates modified were examined as a function of the thickness of the conductive oxide film.     

New technique for the fabrication of conductive polymer/insulating polymer composite films

The electrochemical polymerization of pyrrole on an ITO (indium‐tin oxide)‐coated glass electrode with an insulating film of poly(vinyl alcohol), PVA, produces a flexible composite polymer film with electrical, optical, and electrochemical properties very similar to polypyrrole (PPy). The rate of electrochemical polymerization depends on the diffusion of the electrolyte across the PVA film to the ITO electrode. In particular, hydrophilic solvents easily penetrate into the PVA film. By applying this new process, we demonstrate a unique method of forming electrically conductive patterns in PVA film. It will be possible to develop electrodes for electrical stimulation of the nervous system using a conducting polymer, PPy. By a similar technique we have fabricated poly(3,4‐ethylenedioxythiophene), PEDOT/PVA, composite films and have investigated their electrochemical basic properties. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(4): 1–8, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21055     

Growth characteristics and film properties of gallium doped zinc oxide prepared by atomic layer deposition

We carried out comprehensive studies on structural, optical, and electrical properties of gallium-doped zinc oxide (Ga:ZnO) films deposited by atomic layer deposition (ALD). The gallium(III) isopropoxide (GTIP) was used as a Ga precursor, which showed pure Ga₂O₃ thin film with high growth rate. Using this precursor, conductive Ga doped ZnO thin film can be successfully deposited. The electrical, structural and optical properties were systematically investigated as functions of the Ga doping contents and deposition temperature. The best carrier concentration and transmittance (7.2?×?10²⁰ cm^?3 and 83.5 %) with low resistivity (≈3.5?×?10^?3?Ωcm) were observed at 5 at.% Ga doping concentration deposited at 250 °C. Also, low correlation of deposition temperature with the carrier concentration and film structure was observed. This can be explained by the almost same atomic radius of Ga and Zn atom.     

Effects of oxygen partial pressure on the preferential orientation and surface morphology of ITO films grown by RF magnetron sputtering

In this study, effects of oxygen pressure in the sputtering ambient on the preferential orientation and resultant surface morphology of ITO films grown by RF magnetron sputtering were investigated. ITO film grown with pure Ar gas shows a preferential (400) plane orientation parallel to the substrate surface and a sawteeth-shaped rough surface. ITO film grown in the sputtering ambient of Ar and oxygen mixtures shows a preferential (222) plane orientation and a flat and smooth surface. The differences in the growth rate, surface morphology, and roughness between the preferentially orientated films were discussed in terms of the surface energy of planes. The electrical and optical properties of the films were examined.     

Physical properties of transparent conducting indium doped zinc oxide thin films deposited by pulsed DC magnetron sputtering

Transparent conducting In-doped (1at.%) zinc oxide (IZO) thin films are deposited on glass substrate by bipolar pulsed DC magnetron sputtering. We have investigated the effect of pulse frequency on the physical properties of the IZO films. A highly c-axis oriented IZO thin films were grown in perpendicular to the substrate. At optimal deposition conditions, IZO films with a smoothest surface roughness of ～3.6 nm, a low-resistivity of 5.8?×?10^?3 Ωcm, and a high mobility of 14 cm/Vs were achieved. The optical spectra showed a high transmittance of above 85% in the UV–visible region and exhibited the absorption edge of near 350 nm. In micro-Raman, we observed the three phonon modes of host ZnO, which are E ₂ ^low, E ₂ ^high, and A ₁ modes, and the three additional modes. The origin of three additional modes is attributed to the host lattice defect due to the effect of In dopant and increasing the pulse frequency.     

ZAO特性及其在CIGS电池中的应用

透明导电氧化物薄膜(Transparent Conductive Oxides,简称TCO)用途广泛,介绍了TCO应用于光伏领域中的铜铟镓硒薄膜(CIGS)太阳电池,是CIGS太阳电池中不可缺少的一部分。简要阐述了其可见光范围内的透明性和导电性及其成因,以及作为CIGS薄膜太阳电池中窗口层的作用。将ITO和ZAO透明导电薄膜在CIGS太阳电池的应用进行相比,以掺铝的氧化锌(ZnO∶Al简称ZAO)透明导电薄膜为例,对其性能、制备方法及过程进行了简要阐述,并概括了大面积ZAO薄膜的性能。     

Growth and characterisation of lead zirconate titanate (30/70) on indium tin oxide coated glass for oxide ferroelectric-liquid crystal display application

Abstract

The growth and characterisation of sol-gel lead zirconate titanate (PZT) (30/70) thin films on indium tin oxide (ITO) coated glass have been investigated using X-ray diffraction (XRD), transmitting electron microscopy (TEM) and atomic force microscopy (AFM). Perovskite crystallised at 550°C in a random orientation, and all films showed characteristic rosette formations. A seeding and crystallisation model has been proposed to describe the rosette formation process, which is based on the ease of PbO diffusion through the film. The effect of drying temperature on annealed film properties has been examined and when optimised has been shown to improve electrical properties and film flatness. Incorporation of the PZT films into small prototype liquid crystal displays has been done. Application of pulsed poling voltages to the displays has resulted in bulk alignment of the liquid crystal adjacent to poled regions of the PZT layer which remained after the poling voltages were removed.     

Synthesis and characterization of indium tin oxide (ITO) nanoparticle using gas evaporation process

In this paper, indium tin oxide (ITO) nanoparticle was synthesized by gas evaporation process, and its physical properties such as particle size, specific surface area, crystal structure, and composition ratio according to the heat-treating conditions were investigated to optimize them. The source material was charged in a chamber with vacuum circumstance of 1×10⁻⁵ torr, and the oxygen gas was supplied during evaporation. The In_xO_ySnO_z nanoparticle was synthesized, and the nanoparticle was heat-treated to have optimal point of particle size, crystal structure, and composition, etc. The synthesized nanoparticle was heat-treated with controlling such parameters as heat-treating temperature and environmental gas. Particle size, specific surface area, crystal structure, and concentration ratio of the synthesized ITO nanoparticle by using the method were analyzed with high resolution transmission electron microscopy (HRTEM), BET surface area analyzer, X-ray diffraction (XRD), and energy dispersion spectroscopy (EDS). As a result, in case of ITO nanoparticle synthesized at 300^∘C, its mean particle size is 5 nm and the surface area exceeds 100 m²/g. The XRD analysis indicates that the crystal structure of the particle is cubic one with orientation of (222), (400), (440). Also, the EDS analysis demonstrates that the concentration ratio of indium and tin is 91 at% and 9 at% in the lattice of the ITO nanoparticle. Since the lower sized ITO nanoparticle produces the ITO sputtering target with higher density and the ITO sputtering target with higher density makes the high quality ITO electrode, the synthetic condition of 300^∘C is considered to be optimal condition for enhancing the high quality ITO electrode.     

Characterization of low refractive index SiOCF:H films designed to enhance the efficiency of light emission

An anti-reflection (AR) coating was deposited on the surface of flat panel displays to increase the efficiency of the light emission. The use of low reflective index material can decrease the thickness of the optical coating layer. In this work, low refractive index SiOCF:H films were deposited on P-type (100) Si and glass substrates by the plasma enhanced chemical vapor deposition (PECVD) method using an SiH₄, CF₄ and N₂O gas mixture. The refractive index of the SiOCF:H film continuously decreased with increasing deposition temperature and rf power, exhibiting a minimum value of 1.3854. As the rf power was increased, the fluorine content of the film increased linearly to 5.41% at an rf power of 180 W. The rms surface roughness decreased to 1.0 nm with increasing rf power, with the optimum conditions being observed for the film deposited at an rf power of 140 W.     

ITO靶材的研究与发展

简要介绍了铟(In)的用途及国内铟产业的现状。重点介绍了国内外ITO(铟锡氧化物)靶材的研究现状、主要制备方法(热等静压法、热压法和烧结法)及发展趋势。     

Triglyceride detection using reduced graphene oxide on ITO surface

ABSTRACT

This work demonstrates the formation of highly stable electrochemically reduced graphene oxide (ERGO) thin films on indium tin oxide (ITO) substrates through electrochemical reduction of colloidal suspension containing graphene oxide in deionized water. The structural details, and bio-compatible interactions of the resulting uniformly distributed ERGO/ITO surfaces are studied using various microscopic and spectroscopic characterization tools. Lipase enzyme is immobilized onto the ERGO surface for detection of triglyceride in tributyrine solution. The currently developed ERGO with enhanced electronic properties demonstrates compatibility for establishing specific interaction with various functional groups and could be used as a suitable surface for pursuing experiments in selective detection of bio-entities.     

Characteristics of Bi4Ti3O12 thin films on ITO/glass and Pt/Si substrates prepared by R.F. sputtering and rapid thermal annealing

Bi₄Ti₃O₁₂ thin films are deposited on ITO/glass and Pt/Ti/Si(100) substrates by R.F. magnetron sputtering at room temperature. The films are then heated by a rapid thermal annealing (RTA) process conducted in oxygen atmosphere at temperatures ranging from 550–700^∘C. X-ray diffraction examination reveals that the crystalinity of the films grown on Pt/Ti/Si is better than that of the films grown on ITO/glass under the same fabrication conditions. SEM observation shows that the films grown on Pt/Ti/Si are denser than those grown on ITO/glass substrates. Interactive diffusion between the Bi₄Ti₃O₁₂ film and the ITO film increases with the increase of annealing temperature. The optical transmittance of the thin film annealed at 650^∘C is found to be almost 100% when the effect of the ITO film is excluded. The relative dielectric constants, leakage currents and polarization characteristics of the two films are compared and discussed.     

CuO_x空穴传输层用于钙钛矿太阳能电池

在氧化铟锡(ITO)玻璃导电基底上,通过电化学沉积制备CuO_x薄膜。产物的最高已占轨道(HOMO)能级和最低未占轨道(LUMO)能级分别是-5.31 eV和-3.30 eV,与钙钛矿CH_3NH_3PbI_3的能级匹配。将产物作为空穴传输层,采用反向平面结构:ITO/CuO_x/CH_3NH_3PbI_3/C_(60)/2,9-二甲基-4,7-联苯-1,10-菲罗啉(BCP)/Ag制作钙钛矿太阳能电池,获得最高13.0%的光电转换效率,其中开路电压为0.99 V,短路电流密度为20.2 m A/cm~2,填充因子为65%。     

Experimental Evaluation and Analysis of Electrodynamic Screen as Dust Mitigation Technology for Future Mars Missions

The electrodynamic screen (EDS) is considered to be one of the feasible dust mitigation technologies for future Mars missions. In this paper, the performance of EDS for surface cleaning was characterized with respect to the following operational parameters: 1) the efficiency of screens under both continuous and intermittent operations with different rates of dust deposition; 2) electrical power requirements for the screen operation with respect to dust removal efficiency (DRE), frequency, and excitation frequency; and 3) the optical transmission efficiency of the transparent EDSs and the corresponding power loss, when these screens were placed on solar panels. The average DRE of EDS during continuous dust loading was over 95%, whereas it was 90% when the screen was activated intermittently. Power consumption by EDS, as well as the size and weight of the power supply, is one of the critical factors for its applicability for dust removal from solar panels during future Mars mission. The power consumption by EDS was measured under several dust loadings and using different frequencies and electrical field intensities for the safe operation of power supplies without Paschen breakdown. Experiments were conducted under simulated Martian atmosphere (5.0 mb $hbox{CO}_{2}$ atmosphere) using a screen with an active surface area of 59 $hbox{cm}^{2}$. The average power consumption of screen varied between 1.02 and 2.87 mW. The optical transmission efficiency for a transparent EDS (PET substrate with indium tin oxide electrodes) was measured for a PET screen with ITO electrodes. It was found that placing the transparent EDS on a typical space-type solar panel resulted in a significant obscuration. The power output of the solar panel decreased by 15%.      

The performance and negative bias illumination stability of Hf-In-Zn-O thin film transistors on sputtering conditions

This study examined the performance and stability of amorphous Hf-In-Zn-O (a-HIZO) thin film transistors (TFTs) with different sputtering conditions (DC and RF) for the active layer. The field-effect mobility and stability under negative bias illumination stress for the DC device significantly improved to 13.7 cm²/Vs and ?1.5 V shift of threshold voltage, respectively, compared to those (2.4 cm²/Vs and ?2.4 V shift) for the RF device. It is suggested that the incorporation of hydrogen into the RF-sputtered HIZO film has generated larger defect states in the vicinity of the HIZO/gate insulator interface, which may act as hole trap centers. This work demonstrates that the oxide TFTs combined with DC magnetron sputtering will be a prominent candidate for commercial production of the TFT backplane toward next-generation display applications.     

智能功率模块在电力机车中的应用

以PM100DSA120为例,分析了智能功率模块(Intelligent Power Module,简称IPM)的基本电气特征。提出以IPM作为开关模块并结合空间矢量算法的电力机车电源的设计方案。实验结果表明,该直流电源工作可靠,性能优良。     

Reliability assessment of indium tin oxide thin films by accelerated degradation test

The thermal degradation behavior and reliability of indium tin oxide (ITO) thin films deposited on glass substrates using radio frequency (rf) magnetron sputtering were investigated over the temperature range of 200–250^∘C in air. Accelerated degradation test (ADT) was performed to assess the reliability of ITO films. The lifetime of ITO films under normal operating condition (150^∘C) can be predicted to be 1.148 × 10⁵ h via statistical analysis and modeling of data acquired from ADT. The lifetime of ITO films was also evaluated using finite element analysis (FEA) based on the assumption of oxygen diffusion mechanism.