共查询到19条相似文献,搜索用时 203 毫秒
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在77到292K的范围内,系统研究了含InAs自组装量子点的金属-半导体-金属双肖特基势垒二极管的输运特性.随着温度上升,量子点的存储效应引起的电流回路逐渐减小.在测试温度范围内,通过量子点的共振隧穿过程在电流电压(I-V)曲线中造成台阶结构,且使电流回路随温度的上升急剧减小.根据肖特基势垒的反向I-V曲线,计算了势垒的反向饱和电流密度和平均理想因子.发现共振随穿效应使肖特基势垒在更大的程度上偏离了理想情况,而量子点的电子存储效应主要改变了肖特基势垒的有效势垒高度,从而影响了势垒的反向饱和电流密度
关键词:
自组装量子点
肖特基势垒
电流-电压特性 相似文献
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对单隧穿结和双隧穿结中的库仑阻塞现象进行了介绍,分析了其中电子隧穿的物理过程;然后探讨在单电子盒中如何利用库仑阻塞控制单电子隧穿的物理原理;最后介绍库仑阻塞效应在单电子晶体管中的具体应用及其发展前景. 相似文献
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利用第一原理密度泛函理论计算组装C60形成能和电子结构,用半经典隧穿理论研究了串联C60的电子输运特性。结果显示:六边形对六边形双C60比边对边双C60稳定;库仑阻塞与系统的结构密切相关,并且只有阴极结比阳极结窄时,才会出现库仑阻塞;低温时出现非常明显库仑台阶,温度较高时其被热效应抑制。 相似文献
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利用第一原理密度泛函理论计算组装C60形成能和电子结构,用半经典隧穿理论研究了串联C60的电子输运特性。结果显示:六边形对六边形双C60比边对边双C60稳定;库仑阻塞与系统的结构密切相关,并且只有阴极结比阳极结窄时,才会出现库仑阻塞;低温时出现非常明显库仑台阶,温度较高时其被热效应抑制。 相似文献
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《物理学报》2021,(10)
MgO基磁性隧道结是自旋电子器件研究的热点问题,其温度特性和偏压特性在实际应用中极其重要.因此,亟需在理论上计算得到MgO基磁性隧道结的温度-偏压相图.本文构建了适用于单晶势垒层磁性隧道结的理论.该理论将单晶势垒层视作周期性光栅,利用光学衍射理论处理势垒层对隧穿电子的衍射,因此可以很好地计入隧穿电子波的相干性.根据此理论,同时计入温度和偏压的影响计算了MgO基磁性隧道结的温度-偏压相图.理论结果表明,通过调节MgO基磁性隧道结的铁磁电极半交换劈裂能D、化学势μ以及势垒层周期势v(Kh)可以优化其温度特性和偏压特性.该结果为MgO基磁性隧道结的应用提供了坚实的理论基础. 相似文献
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制备了Cu-Al2O3-MgF2-Au双势垒隧道发光结,分析了结加上一定偏压后的电子隧穿过程.指出由于构成隧道结的绝缘栅薄膜的厚度及禁带宽度的不同而导致双势垒中能级产生分裂,使电子通过栅区时产生共振隧穿现象.根据这一现象,并结合结的I-V特性,对结的发光性能进行了讨论.这种结构的结与普通单势垒MIM结相比,其发光效率(10-6—10-5)提高了近一个数量级,且发光光谱的波长范围及谱峰均向短波长方向
关键词: 相似文献
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L. P. Kouwenhoven N. C. van der Vaart A. T. Johnson W. Kool C. J. P. M. Harmans J. G. Williamson A. A. M. Staring C. T. Foxon 《Zeitschrift für Physik B Condensed Matter》1991,85(3):367-373
We have studied charging effects in a lateral split-gate quantum dot defined by metal gates in the two dimensional electron gas (2 DEG) of a GaAs/AlGaAs heterostructure. The gate structure allows an independent control of the conductances of the two tunnel barriers separating the quantum dot from the two 2 DEG leads, and enables us to vary the number of electrons that are localized in the dot. We have measured Coulomb oscillations in the conductance and the Coulomb staircase in current-voltage characteristics and studied their dependence on the conductances of the tunnel barriers. We show experimentally that at zero magnetic field charging effects start to affect the transport properties when both barrier conductances are smaller than the first quantized conductance value of a point contact at 2e
2/h. The experiments are described by a simple model in terms of electrochemical potentials, which includes both the discreteness of the electron charge and the quantum energy states due to confinement. 相似文献
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D. C. Glattli C. Pasquier U. Meirav F. I. B. Williams Y. Jin B. Etienne 《Zeitschrift für Physik B Condensed Matter》1991,85(3):375-380
A double barrier Single Electron Transistor is realized in two dimensions by confining the 2-D electron gas of a GaAs/GaAlAs heterojunction to a small island by means of Schottky gates. Two gates provide adjustable tunnel barriers and a central gate controls the electron number in the island. The island has small single-particle energy level spacing and forms a metallic island. Periodic conductance oscillations characteristic of Coulomb blockade are observed when the central gate voltage is varied. The ability to vary the tunnel conductance allows us to study the basic physics of the Coulomb blockade: our results show that the quantum charge fluctuation mechanism which limits the tunneling blockade at low temperature is of second order in tunnel barrier transparencies in agreement with the charge Macroscopic Quantum Tunneling (q-MQT) or co-tunneling model. 相似文献
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Tunneling characteristics of a two-dimensional lateral tunnel junction are reported. A pseudogap on the order of Coulomb energy is detected in the tunneling density of states (TDOS) when two identical two-dimensional electron systems are laterally separated by a thin energy barrier. The Coulombic pseudogap remains robust well into the quantum Hall regime until it is overshadowed by the cyclotron gap in the TDOS. The pseudogap is modified by the in-plane magnetic field, demonstrating a nontrivial effect of the in-plane magnetic field on the electron-electron interaction. 相似文献
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A multilevel Anderson model is employed to simulate the system of a nanostructure tunnel junction with any number of one-particle energy levels. The tunneling current, including both shell-tunneling and shell-filling cases, is theoretically investigated via the nonequilibrium Green's function method. We obtain a closed form for the spectral function, which is used to analyze the complicated tunneling current spectra of a quantum dot or molecule embedded in a double-barrier junction. We also show that negative differential conductance can be observed in a quantum dot tunnel junction when the Coulomb interactions with neighboring quantum dots are taken into account. 相似文献
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Hermann Grabert Gert-Ludwig Ingold Michel H. Devoret Daniel Estève Hugues Pothier Cristian Urbina 《Zeitschrift für Physik B Condensed Matter》1991,84(1):143-155
The rate of electron tunneling through normal metal tunnel junctions is calculated for the case of ultrasmall junction capacitances. The so-called Coulomb blockade of electron tunneling at low temperatures is shown to be strongly affected by the external electrical circuit. Under the common experimental condition of a low impedance environment the Coulomb blockade is suppressed for single tunnel junctions. However, a Coulomb gap structure emerges for junctions embedded in a high impedance environment. For a double junction setup a Coulomb blockade of tunneling arises even for low impedance environments due to the charge quantization on the metallic island between the junctions. An approach using circuit analysis is presented which allows to reduce the calculation of tunneling rates in multijunction circuits to those of a single junction in series with an effective capacitance. The range of validity of the socalled local rule and global rule rates is clarified. It is found that the tunneling rate tends towards the global rule rate as the number of junctions is increased. Some specific results are given for a one-dimensional array of tunnel junctions. 相似文献
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P. Jiang I. Yang W. Kang L.N. Pfeiffer K.W. Baldwin K.W. West 《Physica E: Low-dimensional Systems and Nanostructures》2006,34(1-2):203
We report on the low temperature tunneling characteristics of two-dimensional lateral tunnel junctions (2DLTJs) consisting of two coplanar two-dimensional electron systems separated by an in-plane tunnel barrier. The tunneling conductance of the 2DLTJ exhibits a characteristic dip at small voltages—consistent with the phenomenon of zero-bias anomaly in low-dimensional tunnel junctions—and a broad conductance peak at the Coulombic energy scale. The conductance peak remains robust under magnetic fields well into the quantum Hall regime. We identify the broad conductance maxima as the signature of the pseudogap in the tunneling density of states below the characteristic Coulomb interaction energy of the 2DLTJ. 相似文献
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T.A. Knuuttila K.K. Nummila W. Yao J.P. Kauppinen J.P. Pekola 《Physica E: Low-dimensional Systems and Nanostructures》1998,3(4):323
We investigate electron thermalization of tunnel junction arrays installed in a powerful dilution refrigerator whose mixing chamber can produce lattice temperatures down to 3 mK. The on-chip Coulomb blockade thermometers (CBT) against other thermometers at the mixing chamber provide direct information on the thermal equilibrium between the electronic system and the refrigerator. We can detect and discriminate between the heat load delivered through the wiring and that produced by the bias current of the CBT-measurement. The basic heat leak limits the minimum of the electronic temperature to slightly below 20 mK. 相似文献
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电子器件可控性研究在日益追求器件智能化和可控化的当今社会至关重要. 基于第一性原理和量子输运计算, 本文研究了压缩应变载荷对氮化镓(GaN)隧道结基态电学性质和电流输运的影响, 在原子尺度上窥视了氮化镓隧道结的微观压电性, 验证了其内在的巨压电电阻(GPR)效应. 计算结果表明, 压缩应变载荷可以调节隧道结内氮化镓势垒层的电势能降、内建电场、电荷密度和极化强度, 进而实现对隧道结电流输运和隧穿电阻的调控. 在-1.0 V的偏置电压下, -5%的压缩应变载荷将使氮化镓隧道结的隧穿电阻增至4倍. 本研究展现了氮化镓隧道结在可控电子器件中的应用潜力, 也展现了应变工程在调控电子器件性能方面的光明前景. 相似文献
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讨论了高温氘等离子体中的势垒贯穿问题。在现有高温氘等离子体参数下,氘核间必须历经库仑散射与隧道贯穿相结合的复合贯穿才能引发核聚变。冷核聚变与热核聚变在本质上没有区别,都需要借助隧道效应才能发生,它们之间的差异仅在于引发隧道贯穿效应的初始条件不同。因此,在冷核聚变研究中除了过热外.也应有放射性物质的释放。 相似文献