Physical properties of sprayed antimony doped tin oxide thin films:The role of thickness

Transparent conducting antimony doped tin oxide（Sb:SnO₂） thin films have been deposited onto preheated glass substrates using a spray pyrolysis technique by varying the quantity of spraying solution.The structural, morphological,X-ray photoelectron spectroscopy,optical,photoluminescence and electrical properties of these films have been studied.It is found that the films are polycrystalline in nature with a tetragonal crystal structure having orientation along the（211） and（112） planes.Polyhedrons like grains appear in the FE-SEM images. The average grain size increases with increasing spraying quantity.The compositional analysis and electronic behaviour of Sb:SnO₂ thin films were studied using X-ray photoelectron spectroscopy.The binding energy of Sn3d_5/2 for all samples shows the Sn⁴⁺ bonding state from SnO₂.An intensive violet luminescence peak near 395 nm is observed at room temperature due to oxygen vacancies or donor levels formed by Sb⁵⁺ ions.The film deposited with 20 cc solution shows 70%transmittance at 550 nm leading to the highest figure of merit(2.11×10^-3Ω^-1). The resistivity and carrier concentration vary over 1.22×10^-3 to 0.89×10^-3Ω·cm and 5.19×10²⁰ to 8.52×10²⁰ cm^-3,respectively.     

衬底温度对In掺杂CdO薄膜的结构和性能的影响

Transparent indium-doped cadmium oxide（In-CdO） thin films were deposited on quartz glass substrates by pulsed laser deposition（PLD） from an ablating Cd-In metallic target.The effect of substrate temperature on the structural,optical and electrical properties of In-doped CdO thin films were studied in detail.The optical transmittance of In doped CdO films are obviously influenced by the substrate temperature.All films exhibit a transmittance higher than 75%in the visible region.More significantly,In-doping leads to an evident widening of optical band gap from 2.56 to 2.91 eV;and the increase in optical band gap is found to depend on the deposition temperature.It is also seen that the electrical properties of these films strongly depend on the substrate temperature. The In-CdO thin film grown at 300℃has low resistivity(1.15×10^-4Ω·cm),high carrier concentration(5.35×10²⁰ cm^-3),and high mobility（101.43 cm²/（V·s））.     

fmax大于100GHz的AlGaN背势垒结构InAlN-GaN HEMT研究

We report the DC and RF performance of InAlN/GaN high-electron mobility transistors with AlGaN back barrier grown on SiC substrates.These presented results confirm the high performance that is reachable by InAlN-based technology.The InAlN/GaN HEMT sample showed a high 2DEG mobility of 1550 cm²/（V·s） at a 2DEG density of 1.7×10¹³ cm^-2.DC and RF measurements were performed on the unpassivated device with 0.2μm "T" gate.The maximum drain current density at V_GS = 2 V is close to 1.05 A/mm in a reproducible way. The reduction in gate leakage current helps to increase the frequency performance of AIGaN back barrier devices. The power gain cut-off frequency of a transistor with an AIGaN back barrier is 105 GHz,which is much higher than that of the device without an AIGaN back barrier at the same gate length.These results indicate InAlN/GaN HEMT is a promising candidate for millimeter-wave application.     

Source-field-plated Ga2O3 MOSFET with a breakdown voltage of 550 V

Ga_2O_3 metal–oxide–semiconductor field-effect transistors(MOSFETs) with high-breakdown characteristics were fabricated on a homoepitaxial n-typed β-Ga_2O_3 film, which was grown by metal organic chemical vapor deposition(MOCVD) on an Fedoped semi-insulating(010) Ga_2O_3 substrate. The structure consisted of a 400 nm unintentionally doped(UID) Ga_2O_3 buffer layer and an 80 nm Si-doped channel layer. A high k HfO_2 gate dielectric film formed by atomic layer deposition was employed to reduce the gate leakage. Moreover, a source-connected field plate was introduced to enhance the breakdown characteristics. The drain saturation current density of the fabricated device reached 101 mA/mm at V_gs of 3 V. The off-state current was as low as 7.1 ×10^-11 A/mm, and the drain current I_ON/I_OFF ratio reached 10~9. The transistors exhibited three-terminal off-state breakdown voltages of 450 and 550 V, corresponding to gate-to-drain spacing of 4 and 8 μm, respectively.     

介质前后双重臭氧处理实现锗/氧化铪间界面钝化

The physical and electrical properties of a Ge/GeO₂/HfO₂/Al gate stack are investigated.A thin interfacial GeO₂ layer（ 1 nm） is formed between Ge and HfO₂ by dual ozone treatments,which passivates the Ge/high-k interface.Capacitors on p-type Ge substrates show very promising capacitance-voltage（C-V） characteristics by using in situ pre-gate ozone passivation and ozone ambient annealing after high-k deposition,indicating efficient passivation of the Ge/HfO₂ interface.It is shown that the mid-gap interface state density at the Ge/GeO₂ interface is 6.4×10¹¹ cm^-2·eV^-1.In addition,the gate leakage current density of the Ge/GeO₂/HfO₂/Al gate stack passivated by the dual ozone treatments is reduced by about three orders of magnitude compared to that of a Ge/HfO₂/Al gate stack without interface passivation.     

Effect of thickness on optoelectrical properties of Nb-doped indium tin oxide thin films deposited by RF magnetron sputtering

Niobium-doped indium tin oxide （ITO:Nb） thin films are prepared on glass substrates with various film thicknesses by radio frequency （RF） magnetron sputtering from one piece of ceramic target material. The effects of thickness （60-360 nm） on the structural, electrical and optical properties of ITO: Nb films are investigated by means of X-ray diffraction （XRD）, ultraviolet （UV）-visible spectroscopy, and electrical measurements. XRD patterns show the highly oriented （400） direction. The lowest resistivity of the films without any heat treatment is 3.1×10^-4 Ω·cm^-1, and the resistivity decreases with the increase of substrate temperature. The highest Hall mobility and carrier concentration are 17.6 N·S and 1.36×10²¹ cm^-3, respectively. Band gap energy of the films depends on substrate temperature, which varies from 3.48 eV to 3.62 eV.     

Electrical and γ-ray energy spectrum response properties of PbI2 crystal grown by physical vapor transport

Lead iodide single crystal was grown by physical vapor transport method.Two radiation detectors with different configurations were fabricated from the as-grown crystal.The electrical and y-ray response properties at room temperature of the both detectors were investigated.It is found that the dark resistivity of the detectors are respectively 3×10¹⁰Ω·cm for bias electric field parallel to crystal c-axis（E//c） and 2×10⁸Ω·cm for perpendicular to crystal c-axis（E⊥c）.The energy spectrum response measurement shows that both detectors were sensitive to ²⁴¹ Am 59.5 keVγ-rays,and achieved a good energy resolution of 16.8%for the E⊥c-axis configuration detector with a full width at half maximum of 9.996 keV.     

Ga2O3缓冲层厚度对柔性衬底沉积Cu/ITO薄膜性能的影响

Cu and Cu/ITO films were prepared on polyethylene terephthalate （PET） substrates with a Ga2O3 buffer layer using radio frequency （RF） and direct current （DC） magnetron sputtering. The effect of Cu layer thickness on the optical and electrical properties of the Cu film deposited on a PET substrate with a Ga2O3 buffer layer was studied, and an appropriate Cu layer thickness of 4.2 nm was obtained. Changes in the optoelectrical properties of Cu（4.2 nm）/ITO（30 nm） films were investigated with respect to the Ga2O3 buffer layer thickness. The optical and electrical properties of the Cu/ITO films were significantly influenced by the thickness of the Ga2O3 buffer layer. A maximum transmission of 86%, sheet resistance of 45 Ω/□ and figure of merit of 3.96 × 10^-3 Ω^ -1 were achieved for Cu（4.2 nm）/ITO（30 nm） films with a Ga2O3 layer thickness of 15 nm.     

Ohmic contact behaviour of Co/C/4H-SiC structures

The electrical contact properties of Co/4H-SiC structures are investigated.A carbon interfacial layer between a Co film and SiC is used to improve the Ohmic contact properties significantly.The C film is deposited prior to Co film deposition on SiC using DC sputtering.The high quality Ohmic contact and specific contact resistivity of 2.30×10^-6Ω·cm² are obtained for Co/C/SiC structures after two-step annealing at 500℃for 10 min and 1050℃for 3 min.The physical properties of the contacts are examined by using XRD.The results indicate that the Co-based metal contacts have better structural stability of silicide phases formed after the high temperature annealing and carbon-enriched layer is produced below the contact,playing a key role in forming an Ohmic contact through the reduction of effective Schottky barrier height for the transport of electrons.The thermal stability of Au/Co/C/SiC Ohmic contacts is investigated.The contacts remain Ohmic on doped n-type(2.8×10¹⁸ cm^-3) 4H-SiC after thermal aging treatment at 500℃for 20 h.     

Optical and electrical properties of electrochemically deposited polyaniline/CeO2 hybrid nanocomposite film

This paper reports the optical and electrical properties of electrochemically deposited polyaniline （PANI）/cerium oxide（CeO₂） hybrid nano-composite film onto indium-tin-oxide（ITO） glass substrate.UV-visible spectroscopy andⅠ-Ⅴcharacteristic were performed to study the optical and electrical parameters of the electrochemically deposited film.The film exhibited a strong absorption below 400 nm（3.10 eV） with a well defined absorbance peak at around 285 nm（4.35 eV）.The estimated band gap of the CeO₂ sample was 3.44 eV,higher than bulk CeO₂ powder（E_g = 3.19 eV） due to the quantum confinement effect.Optical and electrochemical characteristics indicated that the electrical properties of PANI/CeO₂ hybrid nanocomposite film arc dominated by PANI doping.     

苏丹UPPER ATBARA水电站电气设计特点简介

通过对苏丹UPPER ATBARA水电站机电设计设备编码、执行标准、图纸命名系统等共性特点及发电机电压回路设备、主变压器、220kV GIS、厂用电系统、接地系统、照明系统、电缆系统等电气各个子系统设计特点的简单介绍,着重总结了设计中应重点关注的问题以及与国内设计标准与习惯的不同点,为国际水电站电气设计总结一定的经验参考。     

论变压器直流电阻试验分析

电气试验是电气设备安装工作中的最终检验环节,是电气设备安装质量的有力保证.通过对电气设备及电气系统的试验,可以及时地发现所安装的电气系统、电气设备本身在制造时的缺陷和安装过程中造成的质量问题,以判断新安装的或运行中的电气设备是否能够正常投入运行.可以说电气试验是保证电力设备和电网安全运行的非常重要的一个环节.     

电气自动化在电气工程中的应用研究

电气自动化技术术语电气工程中比较常用的技术之一,通过自动控制与检测功能的有效结合来实现对电气系统控制的适时调节与管理,达到电气系统的安全稳定性.近几年来,我国的电气自动化技术得到突破性的创新,使我国电气系统的自动化程度明显提高.如何进一步提升电气自动化技术的发展是目前研究电气自动化技术的重点.     

高原环境对电气设备的影响及设计方案

本文通过分析高原气候对电气设备的正常工作的影响的基础上,从多个方面进行阐述,并提出高原电气设计需要注重解决的问题以及解决方式.     

Replacing Copper Wires with Carbon Nanotube Wires in Electrical Transformers

Carbon nanotubes, with their unique physical properties, have the potential to outperform conventionally used electrical wiring metals. Any improvement in this area of technology would be of great importance to industry, the economy, and the environment, as the global need for electrical energy and its efficient transfer and conversion rapidly increases. Carbon nanotube fibers, which are assemblies made purely of carbon nanotubes, can uniquely be used in macroscopic electrical applications including electrical wires and devices where the operation is enabled by these conductors. This paper presents details of the working prototype of an electrical machine, a transformer, where conventional copper wires have been replaced with conducting wires made purely of carbon nanotube fibers.     

探讨电气自动化在电气工程中的应用

随着我国经济的迅速发展,科学技术也得到了有效的提升,在科技领域中电气自动化属于一种新型的高新技术,其在经济和科技进步的背景中,同样得到了良好的发展,并且该技术在电气工程中的应用发挥出了重要作用,不仅提高了电气工程的自动化程度,而且为电气工程的发展提供了动力,得到了业内认识的一致好。在实际应用中该技术能够解放电气工程中大量的劳动力,同时对工作效率的提升有着积极作用。因此,电气工程中合理的使用电气自动化技术,已经成为电气工程为了发展的必然趋势,为了能够使其得到更广泛的应用。本文围绕电气工程中电气自动化的应用进行探讨,以此为电气工程的健康发展奠定良好的基础。     

“电机学”中特种电机内容的教学

“电机学”是电气类专业一门重要课程。由于课时不断压缩，特种电机这部分内容往往会被舍弃或由学生自学，因此学习效果很难保证。本文讨论了笔者采用多种有效教学方法和手段，用尽可能少的课时帮助学生掌握几类重要或日常用的特种电机，对电机学的主干知识进行有益补充。     

探讨电气自动化在电气工程中的应用

随着我国经济的迅速发展,科学技术也得到了有效的提升,在科技领域中电气自动化属于一种新型的高新技术,其在经济和科技进步的背景中,同样得到了良好的发展,并且该技术在电气工程中的应用发挥出了重要作用,不仅提高了电气工程的自动化程度,而且为电气工程的发展提供了动力,得到了业内认识的一致好。在实际应用中该技术能够解放电气工程中大量的劳动力,同时对工作效率的提升有着积极作用。因此,电气工程中合理的使用电气自动化技术,已经成为电气工程为了发展的必然趋势,为了能够使其得到更广泛的应用。本文围绕电气工程中电气自动化的应用进行探讨,以此为电气工程的健康发展奠定良好的基础。     

电气工程及其自动化的智能化技术应用研究

伴随电气工程产业的发展,自动化技术处理中通过智能手段的运用,可以针对电气工程的特点,充分发挥智能故障诊断、智能故障控制以及智能项目设计的作用,满足当前电气工程产业的发展需求。本文就智能化技术在电气工程及其自动化中的应用展开探讨。     

继电器在电气工程及其自动化低压电器中的应用研讨

在现代的电气工程及其自动化低压电器的应用当中,保持整个工程的电力正常运转不仅是保证工程顺利的核心,更是保护器械设备、延长机械寿命的关键.因此继电器被广泛应用于电气工程及其自动化低压电器之中.本文通过对继电器的工作原理进行分析,简要阐述了继电器在电气工程及其自动化低压电器中的应用.