GaN-based substrates and optoelectronic materials and devices

In order to solve the problems of GaN heteroepitaxy on sapphire substrate,some techniques were explored.Freestanding GaN substrates have been made by hydride vapor phase epitaxy(HVPE),laser lift-off(LLO),and chemical mechanical polishing techniques.Wafer bending and cracking in the HVPE growth were partly settled by pulsed flow modulation method.High-crystal quality was established for 1.2 mm thick GaN substrate by X-ray diffraction measurement,in which the full width of half maximum values were 72,110 arcsec for(102),(002)peaks.A novel micro-size patterned sapphire substrate(PSS)and a nano PSS were also fabricated.High-power vertical structure light emitting diodes(VSLEDs)have been developed by Au–Sn eutectic wafer bonding,homemade micro-area LLO,and light extraction structure preparation.The high-injection-level active region with low temperature GaN sandwiched layers was used for lowefficiency droop.The light output power of VSLED was achieved as 400 mW driven at 350 mA,and the dominant wavelength is about 460 nm.The structures and properties of strain modulated superlattices(SLs)and quantum wells as well as advanced simulation of carriers transport across the electron blocking layer were investigated in laser diodes.The hole concentration was achieved as high as1.6 9 1018cm-3in AlGaN/GaN SLs:Mg by inserting an AlN layer.High-quality AlGaN epilayers and structures were grown by MOCVD.Some device structures of UV LEDs and detectors were demonstrated.The emission wavelength of 262 nm UV LED has been successfully fabricated.At last,high-quality InN and InGaN materials for solar cell were grown by boundary-temperature-controlled epitaxy and growth-temperature-controlled epitaxy.Hall-effect measurement showed a recorded electron mobility of 3,280 cm2/(V s)and a residual electron concentration of 1.47 9 1017cm-3at 300 K.     

电子科学与技术专业的光电子材料与器件课程教学方法研究

该文阐述了光电子材料与器件课程在电子科学与技术专业教学中的重要地位，并根据笔者自身的教学经验，讨论了电子科学与技术专业教学中光电子材料与器件课程的理论教学和实验教学的内容、教学形式、课时安排与教材选择等。     

氧化锌纳米线的稳定性和电子性质

运用第一性原理方法研究了四种尺寸的ZnO纳米线的结构稳定性和电子性质.结果表明,纳米线的稳定性随着尺寸的增大而增大.所有ZnS纳米线显示了直接带隙半导体特性.由于量子尺寸效应,纳米线的带隙比纤锌矿体材料的带隙大,并且随着纳米线直径的增大而减小.     

蛋白基柔性材料的介观重构及其光电子器件

自然界中的蛋白质材料具有天然丰度、多种化学成分、可调控的性能、优异的生物相容及可降解性能等特点,为柔性光电子器件的发展提供了新的机遇.然而,蛋白质化学稳定性差、机械柔性不可控等缺点使得传统加工技术难以应用在其表面,严重制约了其在柔性电子领域的应用.本文首先以丝蛋白和角蛋白为例介绍了天然蛋白材料的介观重构以及加工技术,阐述了天然蛋白质材料的多级网络结构与其物理性能的关系.在此基础上,侧重介绍它们在柔性传感、发光、晶体管及存储等器件中的应用,最后展望了蛋白基柔性材料在光电子器件发展中所面临的挑战以及发展机遇.     

Nanoscale holographic interferometry for strain measurements in electronic devices

Strained silicon is now an integral feature of the latest generation of transistors and electronic devices because of the associated enhancement in carrier mobility. Strain is also expected to have an important role in future devices based on nanowires and in optoelectronic components. Different strategies have been used to engineer strain in devices, leading to complex strain distributions in two and three dimensions. Developing methods of strain measurement at the nanoscale has therefore been an important objective in recent years but has proved elusive in practice: none of the existing techniques combines the necessary spatial resolution, precision and field of view. For example, Raman spectroscopy or X-ray diffraction techniques can map strain at the micrometre scale, whereas transmission electron microscopy allows strain measurement at the nanometre scale but only over small sample areas. Here we present a technique capable of bridging this gap and measuring strain to high precision, with nanometre spatial resolution and for micrometre fields of view. Our method combines the advantages of moiré techniques with the flexibility of off-axis electron holography and is also applicable to relatively thick samples, thus reducing the influence of thin-film relaxation effects.     

自驱动技术与植入式心脏电子医疗器件

 传统的植入式心脏电子医疗器件电池寿命有限,难以为患者提供长期、不间断的监测和治疗,自驱动技术的出现解决了这一难题。介绍了自驱动技术的类型和原理,从供能、传感和电刺激3个方面回顾了自驱动技术在植入式心脏电子医疗器件中的应用,从自驱动植入式心脏电子医疗器件能源的收集和存储管理、植入物的长期生物相容性、电刺激的生物学效应3个方面展望了自驱动技术与植入式心脏电子医疗器件未来的发展方向。     

大学生电子设计竞赛校园网络平台的构建

阐述校级大学生电子设计竞赛网站的建设意义,研究网站建设的技术支持和主要内容建设,并以开放实验室预约页面的建设为例。指出网站的建设不仅能够为教师与学生提供互动的学习交流的网络平台,而且有利于开放实验室的管理．     

过渡金属掺杂ZnO纳米线结构、电子性质和磁性质

本文采用密度泛函理论系统地研究了过渡金属原子Co和Ni单掺杂和双掺杂ZnO纳米线的结构、电子性质和磁性质.所有掺杂纳米线的束缚能都为负值,表明掺杂过程是放热的. Co原子趋于占据纳米线中间位置,而Ni原子趋于占据纳米线表面位置.所有掺杂纳米线能隙都小于纯纳米线能隙,并显示出直接带隙半导体特性.纳米线的总磁矩主要来源于磁性原子的贡献. Co掺杂纳米线出现了铁磁和反铁磁两种耦合状态;而Ni掺杂纳米线出现了铁磁、反铁磁和顺磁三种耦合状态.     

高校图书馆电子阅览室应为人才培养添砖加瓦

山东农业大学加强图书馆信息资源建设,建成集信息资源、网络、多媒体为一体的电子阅览室,为教学、科研和人才培养提供强大的信息资源和智力支持。本文结合工作实践,探讨电子阅览室建设与管理的经验。     

新一代PEBB控制系统软硬件结构

阐述了国外PEBB(Power Electronic Building Block)的新发展，介绍了一种层次化的硬件结构和基于EOD(Elementary Control Object)的数据流软件结构。利用这种软、硬件结构可构建灵活的、可重配置的及可重利用的电力电子系统。     

Advances in TiS2 for energy storage,electronic devices,and catalysis: A review

As the lightest family member of the transition metal disulfides(TMDs), TiS₂ has attracted more and more attention due to its large specific surface area, adjustable band gap, good visible light absorption, and good charge transport properties. In this review, the recent state-of-the-art advances in the syntheses and applications of TiS₂ in energy storage, electronic devices, and catalysis have been summarized. Firstly, according to the physical presentation of the TiS_...     

掺杂和应变对硅纳米线电子结构与光学性质的调制影响

为了研究掺杂和应变对[111]晶向硅纳米线的电子结构与光学性质的调制影响,基于密度泛函理论体系下的广义梯度近似(general gradient approximation,GGA),采用第一性原理方法开展了相关计算。能带计算表明：空位掺杂和元素掺杂均引入杂质能级,形成了N型和P型半导体材料。单轴应变则进一步减小了带隙,增强了掺杂硅纳米线的导电性,但由于应变也修饰了费米面附近能级的形貌,能带曲率突变影响了体系的导电性能。光学性质计算表明：相比于空位掺杂,元素掺杂更有效地改变了SiNWs的介电函数、吸收系数、折射率与反射率等光学参数,而单轴应变则削弱了元素掺杂的影响。拉应变提升了光吸收的范围和强度,尤其是可见光波段,使掺杂硅纳米线成为优质光伏材料,压应变则降低了对紫外光波段的吸收效率。在紫外区域,拉应变和压应变对掺杂硅纳米线的折射率与反射率的影响相反,在红外和可见光区域影响则一致。本文研究结果为基于应变和掺杂硅纳米线的光电器件设计与应用提供一定的理论参考。     

Coaxial silicon nanowires as solar cells and nanoelectronic power sources

Solar cells are attractive candidates for clean and renewable power; with miniaturization, they might also serve as integrated power sources for nanoelectronic systems. The use of nanostructures or nanostructured materials represents a general approach to reduce both cost and size and to improve efficiency in photovoltaics. Nanoparticles, nanorods and nanowires have been used to improve charge collection efficiency in polymer-blend and dye-sensitized solar cells, to demonstrate carrier multiplication, and to enable low-temperature processing of photovoltaic devices. Moreover, recent theoretical studies have indicated that coaxial nanowire structures could improve carrier collection and overall efficiency with respect to single-crystal bulk semiconductors of the same materials. However, solar cells based on hybrid nanoarchitectures suffer from relatively low efficiencies and poor stabilities. In addition, previous studies have not yet addressed their use as photovoltaic power elements in nanoelectronics. Here we report the realization of p-type/intrinsic/n-type (p-i-n) coaxial silicon nanowire solar cells. Under one solar equivalent (1-sun) illumination, the p-i-n silicon nanowire elements yield a maximum power output of up to 200 pW per nanowire device and an apparent energy conversion efficiency of up to 3.4 per cent, with stable and improved efficiencies achievable at high-flux illuminations. Furthermore, we show that individual and interconnected silicon nanowire photovoltaic elements can serve as robust power sources to drive functional nanoelectronic sensors and logic gates. These coaxial silicon nanowire photovoltaic elements provide a new nanoscale test bed for studies of photoinduced energy/charge transport and artificial photosynthesis, and might find general usage as elements for powering ultralow-power electronics and diverse nanosystems.     

Luminescent and photovoltaic properties of poly（9,9-dioctylfluorene- co-bithiophene） in organic electronic devices

We studied the luminescent and photovoltaic properties of poly(9,9-dioctylfluorene-co-bithiophene)(F8T2) based on ITO/PEDOT:PSS/F8T2/Bphen/LiF(0 or 1 nm)/Al and ITO/PEDOT:PSS/F8T2:PCBM/Bphen/Al.A stable and bright yellow emission was obtained from polymer F8T2,and the electroluminescence power reached 45 ?W at a 15 V driving voltage.Polymer F8T2 shows a broad absorption band from 400 to 500 nm,and has a shorter absorption edge at about 560 nm compared to that of the typical electron donor P3HT(650 nm).The photoluminescence quenching of F8T2 occurs with only a small fraction of blended PCBM due to the effective exciton dissociation at the interface between F8T2 and PCBM.Polymer solar cells(PSCs) using F8T2:PCBM as the active layer show a low power conversion efficiency(PCE) of 0.10% with an open circuit voltage(Voc) of 0.91 V and short circuit current density(Jsc) of 0.23 mA/cm2.The PSCs using F8T2:P3HT:PCBM as the active layer have a Voc of 0.85 V and Jsc of 3.02 mA/cm2,improving the PCE by about 0.90%.We attribute the improved cell performance to the higher number of photons harvested by P3HT molecules.     

Binder- and conductive additive-free Ga2O3 nanowires as a self-healing anode for lithium storage

High-capacity anode materials have stimulated much attention to developing high-performance lithium-ion batteries. However, high-capacity anode materials commonly suffer from the pulverization matter that greatly hinders their practical applications, especially in terms of the high proportion of active materials. In this work, a Ga₂O₃nanowire electrode is synthesized by thermal evaporation and immediately used as an anode without the aid of binders and conductive additives....     

Pulsed metal organic chemical vapor deposition of InAlN-based heterostructures and its application in electronic devices

As a promising group III-nitride semiconductor material, InAlN ternary alloy has been attracted increasing interest and widespread research efforts for optoelectronic and electronic applications in the last 5 years. Following a literature survey of current status and progress of InAlN- related studies, this paper provides a brief review of some recent developments in InAlN-related III-nitride research in Xidian University, which focuses on innovation of the material growth approach and device structure for electronic applications. A novel pulsed metal organic chemical vapor deposition （PMOCVD） was first adopted to epitaxy of InAlN-related heterostructures, and excellent crystalline and electrical properties were obtained. Furthermore, the first domestic InAlN-based high-electron mobility transistor （HEMT） was fabricated. Relying on the PMOCVD in combination with special GaN channel growth approach, high-quality InAlN/GaN double-channel HEMTs were successfully achieved for the first time. Additionally, other potentiality regarding to AlGaN channel was demonstrated through the successful realization of nearly lattice-matched InAlN/AlGaN heterostructures suitable for high-voltage switching applications. Finally, some advanced device structures and technologies including excellent work from several research groups around the world are summarized based on recent publications, showing the promising prospect of InAlN alloy to push group III-nitride electronic device performance even further.     

纳米多孔Co的磷化物制备及其电催化析氢性能

采用脱合金化、水热合成和化学气相沉积制备纳米多孔Co、NiCo(OH)₂/Co和NiCo(OH)₂-P复合电极.通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)等方法表征电极材料的物相和形貌结构.在1 mol·L^-1的KOH溶液中,运用线性扫描伏安曲线(LSV)、交流阻抗谱(EIS)、循环伏安曲线(CV)等测试电极的电催化析氢性能.结果表明：纳米多孔Co、NiCo(OH)₂/Co、NiCo(OH)₂-P电极材料的析氢性能依次增加,化学气相沉积(CVD)磷化后的纳米多孔NiCo(OH)₂-P在10 mA·cm^-2电流密度下,其过电位为139 mV,Tafel斜率为123.57 mV·dec^-1,双电层电容为30.16 mF·cm^-2.经过1 000圈循环伏安耐久性实验后,纳米多孔NiCo(OH)₂-P电极在10 mA·cm^-2电流密度下,析氢过电...     

Direct electrodeposition of ionic liquid-based template-free SnCo alloy nanowires as an anode for Li-ion batteries

SnCo alloy nanowires were successfully electrodeposited from SnCl₂-CoCl₂-1-ethyl-3-methylimidazolium chloride (EMIC) ionic liquid without a template. The nanowires were obtained from the molar ratio of 5:40:60 for SnCl₂:CoCl₂:EMIC at -0.55 V and showed a minimum diameter of about 50 nm and lengths of over 20 μm. The as-fabricated SnCo nanowires were about 70 nm in diameter and featured a Sn/Co weight ratio of 3.85:1, when used as an anode for a Li-ion battery, they presented respective specific capacities of 687 and 678 mAh·g-1 after the first charge and discharge cycle and maintained capacities of about 654 mAh·g-1 after 60 cycles and 539 mAh·g-1 after 80 cycles at a current density of 300 mA·g-1. Both the nanowire structure and presence of elemental Co helped buffer large volume changes in the Sn anode during charging and discharging to a certain extent, thereby improving the cycling performance of the Sn anode.     

Direct electrodeposition of ionic liquid-based template-free Sn Co alloy nanowires as an anode for Li-ion batteries

Sn Co alloy nanowires were successfully electrodeposited from Sn Cl2-Co Cl2-1-ethyl-3-methylimidazolium chloride(EMIC) ionic liquid without a template. The nanowires were obtained from the molar ratio of 5:40:60 for Sn Cl2(25)Co Cl2(25)EMIC at-0.55 V and showed a minimum diameter of about 50 nm and lengths of over 20 μm. The as-fabricated SnCo nanowires were about 70 nm in diameter and featured a Sn/Co weight ratio of 3.85:1, when used as an anode for a Li-ion battery, they presented respective specific capacities of 687 and 678 m Ah·g~(-1) after the first charge and discharge cycle and maintained capacities of about 654 m Ah·g~(-1) after 60 cycles and 539 m Ah·g~(-1) after 80 cycles at a current density of 300 m A·g~(-1). Both the nanowire structure and presence of elemental Co helped buffer large volume changes in the Sn anode during charging and discharging to a certain extent, thereby improving the cycling performance of the Sn anode.