共查询到18条相似文献,搜索用时 140 毫秒
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热感应产生的极化电势可以改变压电半导体结构内的力电物理量,这在人工智能、微机电系统(MEMS)中极具应用价值.文章针对温度梯度作用下的氮化镓(GaN)压电pn结,采用二维压电半导体多场耦合方程和精确的热电物理边界条件,数值分析了温度梯度改变对GaN热压电pn结内极化强度、电势、电场、载流子分布及电流等物理场的影响.结果表明:由于温度梯度场和极化电荷之间存在耦合,热压电pn结电学性能对温度梯度高度敏感,由温度改变产生的热感应极化电荷可以有效调节该结构的开启电压和载流子传输特性,这为操控与温度相关的智能异质结器件电流传输提供了新的方法和理论指导. 相似文献
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图形化氧化锌纳米线的合成和场发射性能研究 总被引:10,自引:10,他引:0
通过简单的热蒸发在ITO电极上合成图形化氧化锌纳米线,利用SEM,XRD,EDX和PL光谱分析氧化锌纳米线的表面形貌、微观结构和光学特性,并测试其场发射性能。SEM表明,ZnO纳米线的直径约为100-200nm,长度大于5um,且均匀长在ITO电极表面。场发射测试表明,图形化ZnO纳米线的开启电场和阈值电场分别为1.6 V/m和4.92 V/m,在电场强度为5.38 V/m时发射电流高达 2.26 mA/cm2,经4.5h场发射测试后发射电流的浮动低于5%。低的开启电场、高的发射电流和好的稳定性表明图形化氧化锌纳米线是一种应用前景广阔的场发射材料。 相似文献
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氧化钨纳米线由于具有长径比较大、导电性好、阈值电场较低、可承受的电流较高等优点,因此在场致电子发射器件中受到人们的广泛关注。但是在氧化钨纳米结构研究发展的过程中,出现了一些技术难题,比如制备温度高(>800℃),制备的氧化钨通常混合多种化学相而导致物性不均匀等,所以束缚了氧化钨纳米线在场发射领域的快速发展。本文采用磁控溅射技术结合化学气相沉积技术在500℃下分别实现了高纯相的WO2和WO3纳米线阵列的定域生长。场发射特性研究结果表明:所制备的WO3纳米线阵列的开启电场低至0.65MV/m,阈值电场约为2.9MV/m,最大电流密度达到18.3A/cm2;WO2纳米线阵列的开启电场低至0.8MV/m,阈值电场为2.46MV/m,最大电流密度达到12.1mA/cm2。这表明在低温下制备的氧化钨纳米线阵列在场致电子发射领域具有非常广阔的应用前景。 相似文献
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衬底温度对ZnO:Al薄膜结构和性能的影响 总被引:1,自引:0,他引:1
利用射频磁控溅射法采用氧化锌铝(98%ZnO+2%Al2O3)为靶材在普通载玻片上制备了ZAO(ZnO:al)薄膜,研究了衬底温度对薄膜晶体结构,电学和光学性能的影响.利用X射线衍射仪、场扫描电镜对薄膜的结构及表面形貌进行了分析,利用分光光度计和电阻测试仪分别测试了薄膜的光电学性能.结果表明,衬底温度对薄膜结构及光电学性能影响最大.溅射功率120 W、衬底温度300℃、工作气压0.6 Pa制得的薄膜具有良好的光电学性能(可见光平均透过率为79.49%(考虑衬底的影响,电阻率为4.99×10-2 Ω·cm). 相似文献
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氧化锌纳米线晶体管的电学特性研究 总被引:1,自引:0,他引:1
成功制作了氧化锌纳米线沟道场效应晶体管器件,所制作器件的电学性能通过I-V测试进行了分析。使用了水浴法生长了单晶性完整的氧化锌纳米线,该纳米线被用作背栅场效应晶体管的沟道,采用光刻方式制备的器件具有良好的直流特性,进行退火后进一步改善器件的源漏接触,提高器件性能,最终制备成功的场效应晶体管显示出p型MOS的特性,其开关态电流比达到105。在Vds=2.5 V时,跨导峰值为0.4μS,栅氧电容约为0.9 fF,器件夹断电压Vth为0.6 V,沟道迁移率约为87.1 cm2/V.s,计算得到氧化锌纳米线载流子浓度ne=6.8×108 cm-3。在Vgs=0 V时,器件沟道电阻率为100Ω.cm。 相似文献
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Mohammed Riaz Jinhui Song Omer Nur Zhong Lin Wang Magnus Willander 《Advanced functional materials》2011,21(4):628-633
The piezoelectric power generation from ZnO nanowire arrays grown on different substrates using different methods is investigated. ZnO nanowires were grown on n‐SiC and n‐Si substrates using both the high‐temperature vapor liquid solid (VLS) and the low‐temperature aqueous chemical growth (ACG) methods. A conductive atomic force microscope (AFM) is used in contact mode to deflect the ZnO nanowire arrays. No substrate effect was observed but the growth method, crystal quality, density, length, and diameter (aspect ratio) of the nanowires are found to affect the piezoelectric behavior. During the AFM scanning in contact mode without biasing voltage, the ZnO nanowire arrays grown by the VLS method produced higher and larger output voltage signal of 35 mV compared to those grown by the ACG method, which produce smaller output voltage signal of only 5 mV. The finite element (FE) method was used to investigate the output voltage for different aspect ratio of the ZnO nanowires. From the FE results it was found that the output voltage increases as the aspect ratio increases and starts to decreases above an aspect ratio of 80 for ZnO nanowires. 相似文献
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利用静电场理论计算了背栅极冷阴极器件的纳米线附近电场,给出电场分布的表示式及J-V曲线,并分析了几何参数对纳米线顶端表面电场的影响.结果表明,纳米线顶端表面产生巨大的电场,随着离纳米线顶端表面距离的增大,电场迅速下降;纳米线突出栅孔的长度(L-d1)越大,纳米线半径r0、栅孔半径R以及栅极与阳极间距d2越小,则纳米线顶端表面电场越强,而d2较大时d2对表面电场的影响很弱;纳米线顶端边缘电流密度J随着阳极与栅极电压的增加而指数增大. 相似文献
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The nanowires and nanotubes are being considered as the best candidates for high-speed applications. It is shown that the high mobility does not always lead to higher carrier velocity. The ultimate drift velocity due to the high-electric-field streaming are based on the asymmetrical distribution function that converts randomness in zero-field to streamlined one in a very high electric field. The limited drift velocity is found to be appropriate thermal velocity for a nondegenerately doped sample of silicon, increasing with the temperature, but independent of carrier concentration. However, the limited drift velocity is the Fermi velocity for a degenerately doped silicon nanowire, increasing with carrier concentration but independent of temperature. The results obtained are applied to the modeling of the current-voltage characteristics of a nanowire transistor. 相似文献
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Haibo Zeng Xijin Xu Yoshio Bando Ujjal K. Gautam Tianyou Zhai Xiaosheng Fang Baodan Liu Dmitri Golberg 《Advanced functional materials》2009,19(19):3165-3172
Here, a facile and effective route toward full control of vertical ZnO nanorod (NR)/nanowire (NW) arrays in centimeter‐scale areas and considerable improvement of field‐emission (FE) performance is reported. Controlled deformation of colloidal crystal monolayer templates is introduced by heating near glass‐transition temperature. The NR/NW density, uniformity, and tapering were all adjusted through selection of template size and deformation, and electrolyte composition. In line with the adjustments, the field‐emission performance of the arrays is significantly improved. A low turn‐on electric field of 1.8 V µm?1, a field‐enhancement factor of up to 5 750, and an emitting current density of up to 2.5 mA cm?2 were obtained. These improved parameters would benefit their potential application in cold‐cathode‐based electronics. 相似文献
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Ultrahigh Tunability of Room Temperature Electronic Transport and Ferromagnetism in Dilute Magnetic Semiconductor and PMN‐PT Single‐Crystal‐Based Field Effect Transistors via Electric Charge Mediation 下载免费PDF全文
Qiu‐Xiang Zhu Ming‐Min Yang Ming Zheng Ren‐Kui Zheng Li‐Jie Guo Yu Wang Jin‐Xing Zhang Xiao‐Min Li Hao‐Su Luo Xiao‐Guang Li 《Advanced functional materials》2015,25(7):1111-1119
Multiferroic heterostructures composed of complex oxide thin films and ferroelectric single crystals have aroused considerable interest due to the electrically switchable strain and charge elements of oxide films by the polarization reversal of ferroelectrics. Previous studies have demonstrated that the electric‐field‐control of physical properties of such heterostructures is exclusively due to the ferroelectric domain switching‐induced lattice strain effects. Here, the first successful integration of the hexagonal ZnO:Mn dilute magnetic semiconductor thin films with high performance (111)‐oriented perovskite Pb(Mg1/3Nb2/3)O3‐PbTiO3 (PMN‐PT) single crystals is reported, and unprecedented charge‐mediated electric‐field control of both electronic transport and ferromagnetism at room temperature for PMN‐PT single crystal‐based oxide heterostructures is realized. A significant carrier concentration‐tunability of resistance and magnetization by ≈400% and ≈257% is achieved at room temperature. The electric‐field controlled bistable resistance and ferromagnetism switching at room temperature via interfacial electric charge presents a potential strategy for designing prototype devices for information storage. The results also disclose that the relative importance of the strain effect and interfacial charge effect in oxide film/ferroelectric crystal heterostructures can be tuned by appropriately adjusting the charge carrier density of oxide films. 相似文献
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Y.‐K. Tseng C.‐J. Huang H.‐M. Cheng I.‐N. Lin K.‐S. Liu I.‐C. Chen 《Advanced functional materials》2003,13(10):811-814
Needle‐like ZnO nanowires with high density are grown uniformly and vertically over an entire Ga‐doped conductive ZnO film at 550 °C. The nanowires are grown preferentially in the c‐axis direction. The X‐ray diffraction (XRD) θ‐scan curve shows a full width at half maximum (FWHM) value of 2°. This indicates that the c‐axes of the nanorods are along the normal direction of the substrate surface. The investigation using high‐resolution transmission electron microscopy (HRTEM) confirmed that each nanowire is a single crystal. A room‐temperature photoluminescence (PL) spectrum of the wires consists of a strong and sharp UV emission band at 380 nm and a weak and broad green–yellow band. It reveals a low concentration of oxygen vacancies in the ZnO nanowires and their high optical quality. Field electron emission from the wires was also investigated. The turn‐on field for the ZnO nanowires was found to be about 18 V μm–1 at a current density of 0.01 μA cm–2. The emission current density from the ZnO nanowires reached 0.1 mA cm–2 at a bias field of 24 V μm–1. 相似文献