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1.
对基于Top-Down加工技术的纳米电子器件如:单电子器件、共振器件、分子电子器件等的研究现状、面临的主要挑战等进行了讨论.采用CMOS兼容的工艺成功地研制出单电子器件,观察到明显的库仑阻塞效应;在半绝缘GaAs衬底上制作了AlAs/GaAs/In0.1 Ga0.9As/GaAs/AlAs双势垒共振隧穿二极管,采用环型集电极和薄势垒结构研制的共振隧穿器件,在室温下测得其峰谷电流比高达13.98,峰电流密度大于89kA/cm2;概述了交叉阵列的分子存储器的研究进展.  相似文献   

2.
对基于Top-Down加工技术的纳米电子器件如:单电子器件、共振器件、分子电子器件等的研究现状、面临的主要挑战等进行了讨论.采用CMOS兼容的工艺成功地研制出单电子器件,观察到明显的库仑阻塞效应;在半绝缘GaAs衬底上制作了AlAs/GaAs/In0.1 Ga0.9As/GaAs/AlAs双势垒共振隧穿二极管,采用环型集电极和薄势垒结构研制的共振隧穿器件,在室温下测得其峰谷电流比高达13.98,峰电流密度大于89kA/cm2;概述了交叉阵列的分子存储器的研究进展.  相似文献   

3.
陈德媛 《半导体学报》2011,32(8):083004-4
采用等离子体淀积和原位氧化技术,并结合后续的热退火处理制备了nc-Si/SiO2 多层膜结构。通过电流电压特性对室温下器件中的载流子输运过程进行了表征。在正向和反向偏压下的电流电压特性曲线中都表现出了由于共振隧穿引起的负微分电导。共振隧穿产生的峰值电流对应的电压值与器件结构中的势垒层厚度相关,势垒层越厚,发生隧穿的峰值电压越高。文中通过器件的能带结构简图和等效电路图对正向、反向偏压下的共振隧穿峰值电压差异进行了细致的分析。  相似文献   

4.
对基于Top-Down加工技术的纳米电子器件如:单电子器件、共振器件、分子电子器件等的研究现状、面临的主要挑战等进行了讨论. 采用CMOS兼容的工艺成功地研制出单电子器件,观察到明显的库仑阻塞效应;在半绝缘GaAs衬底上制作了AlAs/GaAs/In0.1Ga0.9As/GaAs/AlAs双势垒共振隧穿二极管,采用环型集电极和薄势垒结构研制的共振隧穿器件,在室温下测得其峰谷电流比高达13.98,峰电流密度大于89kA/cm2;概述了交叉阵列的分子存储器的研究进展.  相似文献   

5.
在GaAs/AlAs(10nm/2nm)弱耦合掺杂超晶格I-V曲线的第一个平台上,我们首先观测到了直流偏压下的室温微波振荡.观测到的最高振荡频率可达142MHz.这种由级联隧穿引起的振荡在测试温度范围14~300K内始终存在.经分析发现:由于垒层仅有2nm,电子隧穿通过垒层的几率很高,相比之下,电子越过势垒而产生的热离子发射电流要小得多.在温度低于300K时,超晶格内的纵向输运机制是级联共振隧穿和声子辅助隧穿.这是室温仍然能观测到自维持振荡的主要原因.由于实现振荡所施加的偏压比较低(在室温下偏压范围大约为  相似文献   

6.
首先介绍了共振隧穿理论和一种新效应--介观压阻效应,对AlxGa1-xAs/GaAl/AlxGa1-xAs共振隧穿双势垒结构的轴向施加压应变作了分析,然后计算了轴向应变对垒宽和垒高的影响,对透射系数和隧穿电流用Matlab作了仿真.发现压应变可以使隧穿电流线性增加,偏压不同电流增加的速率也不同,为设计共振隧穿器件提供了理论依据.  相似文献   

7.
在2-t-butyl-9,10-di-(2-naphthyl)anthracene(TBADN)/tris(8-hydroxyquinoline)aluminum(Alq3)界面及TBADN/4'7-diphyenyl-1,10-phenanthroline(Bphen)界面上插入Gaq薄膜作为阶梯势垒,使有机电致发光器件的电子注入得到改善.由于Gaq(2.9 eV)的LUMO(分子最低空余轨道能级)位于Alq3(3.1 eV)(或 Bphen(3.0 eV))的LUMO和TBADN的LUMO(2.8 eV)之间,形成了从Alq3(或Bphen)经Gaq到TBADN的势垒阶梯,提高了电子注入,进而提高了器件效率.实验表明:与没有阶梯势垒的器件相比,无论是单一电子器件还是完整器件,在相同电流密度下,具有阶梯势垒的器件的电压都有所下降.在电流密度为20 mA/cm2时,当电子传输层为Alq3时,单一电子器件的电压从7.9 V降到4.9 V,完整器件的电压从7 V降到5.8 V;当电子传输层为Bphen时,单一电子器件的电压从4.2 V降到3.1 V,完整器件的电压从6.2 V降到5.1 V.在电流密度为200 mA/cm2,Alq3为电子传输层时,亮度从1 992 cd/m2升到3 281 cd/m2,最高亮度达到3 420 cd/m2,Bphen为电子传输层时,亮度从1 745 cd/m2 升到2 876 cd/m2,最高亮度达到3 176 cd/m2.本文运用能级隧穿理论对上述现象进行了解释.  相似文献   

8.
共振隧穿是电子的隧穿概率在某一个能量值附近以尖锐的峰值形式出现的隧穿,是目前为止最有希望应用到实际电路和系统的量子器件之一,其特点是器件的响应速度非常快。本文用传递矩阵的方法分别计算了在外加偏压下,对称双势垒、三势垒应变量子阱结构的透射系数与入射电子能量和隧穿电流与偏置电压的关系,模拟了应变多量子阱结构的隧穿系数和I-V特性曲线。计算得到隧穿电流峰值位置与实验测试值符合得很好,对于设计共振隧穿二极管并为进一步实验提供理论指导具有重要的意义。  相似文献   

9.
制备了与AlGaN/GaN高电子迁移率晶体管栅极结构与性能等效的圆形肖特基二极管结构,测量了器件的变温电流-电压特性,研究其在正向与反向偏压条件下的载流子输运过程。结果表明:(1)正向低偏压线形区的电流主要为缺陷辅助隧穿电流,而体电阻效应显著的高偏压区,经典热发射机制占主导地位;(2)AlGaN势垒层中的极化电场对器件的反向漏电流起重要作用,载流子的主要输运过程为Frenkel-Poole发射机制。  相似文献   

10.
TM27 2003020047处理具有任意形状势垒的磁性隧道结中电子输运的一个简单方法/谢征微,李伯减(中国科学院物理所)“物理学报一2002,51(2)一399一405在引。nczewski自由电子模型的基础上.提出了一个可用于处理具有任意形状势垒的磁性隧道结中磁电子输运的简单方法,并以三种常见构形的势垒,即梯形势垒,计入了镜像势的梯形势垒和抛物线势垒为例,讨论了势垒形状对隧穿磁电阻及其随偏压变化的影响.图6参16(午)TM271 2003020048纳米Fe一1 n203颗粒膜的磁性和巨磁电阻效应/张林,刘宜华,黄宝歌(山东大学)“科学通报一2002,47(19)一1465一1468采用射…  相似文献   

11.
研究了含双δ势垒的三终端铁磁/半导体/铁磁异质结隧穿电导的性质,结果表明:隧穿电导随半导体长度的增加作周期性等幅振荡,δ势垒强度、Rashba自旋轨道耦合强度、外加磁场强度及方向对隧穿电导均有不同的影响.  相似文献   

12.
The pursuit of miniaturization of magnetic electronic components spurs intensive theoretical and experimental researches on designing molecule-scale magnetic devices. Controlling the transport properties is one of the most vital focuses for magnetic molecular devices. In this work, magnetic devices constructed by a single epindolidione (Epi) molecule (5,11-dihydrodibenzo[b,g][1,5]naphthyridine-6,12-dione) bridging two zigzag graphene nanoribbon (zGNR) electrodes are theoretically designed. The Epi molecule can be converted between the keto and enol forms, which is confirmed by first principle molecular dynamics method. The influences of intramolecular proton transfer and the bridging manner between the core molecule and zGNR electrodes on the magnetic transport properties are investigated. Spin-resolved current-voltage (I-V) curves show that both the keto and enol devices display remarkable spin filtering effect. However, the effect of intramolecular proton transfer on the electron transport properties depends on the bridging manner between the Epi molecule and zGNR electrodes. When the Epi molecule is connected to zGNR electrodes with 4,7-sites (A bridging manner), the electron transport properties of molecular junctions are hardly affected by the intramolecular proton transfer. On the contrary, the conductance of the molecular junctions is significantly modulated by the intramolecular proton transfer when the Epi molecule is connected to zGNR electrodes with 4,4-sites (B bridging manner). Further analysis reveals that the high spin filtering effect originates from stronger coupling between spin-up edge electronic states of zGNR electrodes and states of the core molecule. With B bridging manner, the conjugation characteristics of the Epi molecule as well as the transmission pathway of tunneling electrons can be largely modulated by the intramolecular proton transfer. Our work proposes a feasible way to control the conductance of single-molecule junctions by taking advantage of intramolecular proton transfer.  相似文献   

13.
Resonant tunneling of electrons is important for the manufacture of high-speed electronic oscillators and the electron injection control in quantum cascade lasers. In this work, room temperature negative differential resistance (NDR) in AlGaN/GaN double barrier structure with AlN/GaN digital alloy (DA) barriers is demonstrated. The peak-to-valley current ratio (PVCR) ranges from 1.1 to 1.24 at room temperature and becomes 1.5 to 2.96 at low temperatures, whereas no NDR is observed in double barrier structures with conventional ternary AlGaN barriers. The room temperature NDR together with the high PVCR at low temperature is attributed to the suppression of alloy disorder scattering by introducing AlN/GaN DA barriers. This work presents the successful control of phase-coherent electron transport in III-nitride heterostructures and is expected to benefit the future design of nitride-based resonant tunneling structures and high-speed electronic devices.  相似文献   

14.
On superluminal tunneling   总被引:1,自引:0,他引:1  
Photonic tunneling is currently of theoretical and applied interest. In a previous review, faster-than-light (i.e. superluminal) photonic tunneling was discussed (Progr. Quantum Electron. 21 (1997) 81). Recently, superluminal photonic pulse transmission and reflection have been measured at microwave and infrared frequencies. It seems clear that superluminal photonic and electronic devices will become a reality in the near future.

In the present report, we introduce new experimental and theoretical data on superluminal tunneling and reflection. Data of reflection by barriers have evidenced the nonlocal nature of tunneling. Asymmetric barriers have revealed a strange asymmetric reflection behavior in time.

The principle of causality is not violated by a superluminal speed even though the time duration between cause and effect can be shortened compared with a luminal interaction exchange. An empirical relationship independent of the barrier system is found for the photonic tunneling time. This relation seems to be universal for all kind of tunneling processes in the case of single opaque barriers. We show that the superluminal velocity can be applied to speed up photonic modulation and transmission as well as to improve microelectronic devices.  相似文献   


15.
Our ability to manipulate atoms and molecules on an individual basis has opened a new experimental frontier that makes feasible the quest for single molecular-scale devices as successors to the transistor. Here, we discuss our realization of the first amplifier using a single fullerene molecule less than 1 nm in diameter as the active element. This C60 molecular device works by electromechanical modulation of virtual resonance quantum mechanical tunneling. The equivalent of the grid is achieved by the purely mechanical action of compressing the C60 cage voltage. This action reversibly changes the internal electronic structure of the molecule, increasing its conductance in a continuous manner. The first embodiment provides experimental verification with a measured voltage gain of five. The implications of these results indicate a new approach to electronics on the nanoscale, working in a new transport regime for the three-terminal devices. Going beyond these experiments, we discuss possible approaches of creating single-molecule devices and the advantages they promise  相似文献   

16.
Quantum mechanical tunneling through insulating barriers has received considerable attention in recent years, especially in metal-insulator-metal systems and pn junctions. It is the purpose of this paper to discuss tunneling in the MIS contact. In this paper we define the d.c. currents which flow and then calculate the voltage distribution in the contact. It is found that as long as the semiconductor spacecharge region is of the order of the insulator thickness ( 50 Å) considerable voltage drops across the semiconductor. Using this, a voltage region of low conductance is shown to exist, over which the metal Fermi level is opposite the forbidden gap of the semiconductor. This region is shown to be greater than the semiconductor energy gap. In addition, the a.c. frequency dependent currents which flow in an MIS contact due to interface states are calculated. It is shown that interface states can contribute to the a.c. conductance via two mechanisms; time lag in trapping and recombination of carriers in the semiconductor bands and tunneling via interface states. Both of these mechanisms are discussed and the conditions under which one or the other make the major contribution to the a.c. conductance is analyzed.  相似文献   

17.
对硅基HgCdTe中波器件进行了变温电流电压特性的测试和分析。测量温度从30K到240K,得到R0对数与温度的1000/T的实验曲线及拟合结果。同时选取60K、80K及110K下动态阻抗尺与电压V的曲线进行拟合分析。研究表明在我们器件工作的温度点80K,零偏压附近主要的电流机制是产生复合电流和陷阱辅助隧穿电流。要提高器件的水平,必须降低陷阱辅助隧穿电流和产生复合电流对暗电流的贡献。  相似文献   

18.
Electron tunneling in a heterostructure with a single doped barrier was investigated. Analysis of the experimental data showed that all features in the tunneling conductance are due to electron tunneling between two-dimensional electron sheets which appear on different sides of the barrier as a result of ionization of impurities in the barrier. Electron transport between the two-dimensional electron sheets and three-dimensional contact regions does not introduce significant distortions in the measured tunneling characteristics. In such structures there is no current flow along the two-dimensional electron gas; such a current ordinarily makes it difficult to investigate tunneling between two-dimensional electronic systems in magnetic fields. Fiz. Tekh. Poluprovodn. 32, 602–606 (May 1998)  相似文献   

19.
The electrical properties of two molecular wires?a novel aryl moiety, 6‐(5‐pyridin‐2‐ylpyrazin‐2‐yl)pyridine‐3‐thiol (PPPT), and the well studied 1,1';4',1''‐terphenyl‐4‐thiol (TPT)?organized in self‐assembled monolayers (SAMs) are measured using metal–molecule–metal (MMM) mercury‐drop junctions. Current measured at the same bias voltage through PPPT is found to be more than one order of magnitude lower than through TPT. To interpret and understand these results, characterization of the structure, organization of the SAMs, and theoretical analyses of the molecular systems are discussed. X‐ray photoelectron spectroscopy (XPS) and near‐edge X‐ray absorption fine structure spectroscopy (NEXAFS) indicate that although PPPT forms high‐quality SAMs on both Au and Ag substrates, it exhibits a lower packing density (by 20 %) and less orientational order than TPT. In addition, electronic structure calculations with density functional theory (DFT) reveal that the electron‐withdrawing nitrogen atoms in the PPPT aryl backbone stabilize the valence molecular electronic structure and pull negative charge from the thiol sulfur. This behavior can influence both charge‐injection barriers and metal–molecule binding interactions in the MMM junctions. The current–voltage data are interpreted on the basis of a hole‐tunneling, through‐bond mechanism. Conductance analysis through a model for off‐resonant tunneling transport suggests that a comparatively small difference in the charge‐injection barrier can explain the factor of ten difference in observed conduction.  相似文献   

20.
We present results for the resonant electronic transmission through graphene-based single and double barriers as a function of the incident wave vector, the widths and heights of the barriers, and the separation between them. Resonant features in the transmission result from resonant electron states in the wells or hole states in the barriers and strongly influence the ballistic conductance of the structures.  相似文献   

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