共查询到20条相似文献,搜索用时 0 毫秒
1.
E. T. Koenig C. I. Huang B. Jogai K. R. Evans C. E. Stutz D. C. Reynolds 《Journal of Electronic Materials》1991,20(3):223-225
The uniformity of electronic device characteristics is dependent on the uniformity of the epitaxial material. Uniformity is
particularly important for resonant tunneling diodes where small changes in well or barrier thickness can have profound effects
on the diode current-voltage characteristics. The variability of these characteristics due to growth rate nonuniformity for
epitaxial structures grown by molecular beam epitaxy has been documented and the magnitude of the thickness variations analyzed
using photoluminescence and a theoretical model. An increase of 17 meV was observed in the quantum well ground state, corresponding
to a 15% thinning of the well from the center to the edge of the substrate. 相似文献
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M.L. Leadbeater L. Eaves M. Henini O.H. Hughes G. Hill M.A. Pate 《Solid-state electronics》1989,32(12):1467-1471
The current-voltage characteristics of an asymmetric double barrier resonant tunneling device show a butterfly-shaped hysteresis loop in which, for a range of voltage, the off-resonant current exceeds the resonant current. This “inverted bistability” is due to the effects of space charge buildup in the quantum well. Magnetoquantum oscillations in the tunnel current with
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are used to investigate the distribution of charge within the device and the intersubband scattering processes which control the charge buildup. 相似文献
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S. Bending A. Peck J. Leo K. v. Klitzing
P. Gu
ret H. P. Meier 《Solid-state electronics》1989,32(12):1161-1165Preliminary results are presented for a 3-terminal device fabricated by incorporating a narrow quantum well into the collector barrier of a unipolar hot electron transistor. The structure allows unique studies of the mechanism of resonant tunneling in which the carrier injection energy and the bias across the double barrier can be independently varied. The transistor clearly shows an additional current collection threshold representing as much as 10% of the injected current attributable to tunneling via the single subband in the quantum well. This interpretation is confirmed by measurements in perpendicular and parallel magnetic fields despite the fact that theoretical estimates of the resonant tunneling current without scattering are many orders of magnitude smaller, and there are strong indications that elastic scattering in the well is responsible for the enormous discrepancy. The data tend to support proposals (Guéret, 1989a, 1989b; Wolak, 1988) that elastic scattering is responsible for the large valley currents in resonant tunneling diodes, and it appears that the tunnel process may not be completely incoherent as has frequently been assumed up to now. 相似文献
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We analyse theoretically the small-signal ac response of a resonant tunneling double-barrier semiconductor diode using the sequential tunneling approach. Electrostatic feedback effects due to space charge buildup in the quantum well are included in the analysis. The results are expressed in terms of an equivalent circuit which is used to interpret measurements of the capacitance of an asymmetric double-barrier structure at low frequencies (< 1 MHz). The frequency dependence of the real and imaginary parts of the impedance at microwave frequencies are also discussed. 相似文献
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We discuss effects of structural imperfections on the I-V characteristics and local density-of-states of semiconductor double-barrier heterostructures. Using a linear-chain model for GaAs/AlGaAs structures, we simulate fluctuations in layer thicknesses, defects at the heterointerfaces, and disorder. 相似文献
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A. C. Campbell V. P. Kesan T. R. Block G. E. Crook D. P. Neikirk B. G. Streetman 《Journal of Electronic Materials》1989,18(5):585-588
Double barrier GaAs/AlAs tunneling structures with typical 2.5:1 room temperature peak-to-valley current ratios are examined
using Deep Level Transient Spectroscopy. Deep level trap concentrations are found to be much higher in samples grown at 550°
C compared to those grown at 650° C. For devices grown at 550° C, an impedance switch-ing effect due to a high concentration
of deep levels is observed. The peak-to-valley ratio of the tunneling devices is largely unaffected by the growth temperatures
in this range, indicating that higher growth temperatures can be employed to grow resonant tunnel-ing diodes than previously
suggested in the literature. 相似文献
7.
Transistors employing resonant tunneling injection of hot electrons into a thin quantum well base region have been fabricated. The base region in these transistors is formed by a narrow bandgap material like InGaAs so that the first level is a confined one lying below the Fermi level in the contact regions. This results in charge transfer into the bound state in the quantum well thus allowing independent control of the base electrostatic potential. Theoretical calculations showing the importance of various device parameters in the design of a resonant tunneling transistor are presented and preliminary results showing the capability of transistor action in such devices are presented. 相似文献
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Using the Wigner function formalism, we study the effects of structural parameters on the DC I-V characteristics and on the large-signal transient response of the resonant tunneling diode. We model two types of structures of GaAs/AlxGa1-xAs; first, with symmetric barriers ranging from 3 to 8 nanometers in thickness separated by a 5 nanometer well, and second with a well varying from 3 to 8 nanometers between 3 nanometer barriers. Experimental variation of the barrier thickness and height changes the peak-to-valley ratio in the I-V curve, as predicted by elementary models of tunneling structures. This stems directly from the changes in tunneling probabilities. For the DC studies, we show that the peak-to-valley ratio in the I-V curve is a function of the resonance width, which depends both on the well and barrier thickness. The location of the peak on the I-V curve depends on the location of the resonant energy, which is a function of the well width. Transient switching behavior is compared to earlier numerical studies of tunneling times of wave packets. Charge storage stabilizes the position of the resonant state, thus damping the transients. Consequently, wider barriers yield faster transient settling times, in agreement with the tunneling time results which predicted longer charge storage times for thicker barriers. 相似文献
9.
An experimental apparatus and procedure using noise measurement techniques have been developed in order to identify conduction mechanisms in RTDs due to defect assisted tunneling. The theory of noise measurements is discussed as the basis for the appropriate modelling of RTD noise data. The activation energies and capture cross-sections have been determined in a typical RTD for each of three distinct trap levels. A conjecture is made as to the physical location of the traps. This interpretation yields qualitative behavior consistent with the known bias and temperature dependence of the experimental results. 相似文献
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简要介绍了RTD(共振隧穿二极管)的微分负阻特性及其等效电路,通过对实际AlAs/InxGa1-xAs/GaAs双势垒共振隧穿结构I-V曲线拟合,得出RTD的Pspice等效电路模型参数。采用Pspice软件建立了RTD的等效电路模型,并对其微分负阻特性进行了仿真,仿真结果与测试结果基本吻合。利用所建立的模型,对RTD的基本应用电路:反相器、非门、与非门和或非门进行了仿真模拟。结果表明,该类电路能够正确实现其逻辑功能。最后,对基于RTD的振荡电路进行了仿真,仿真频率与实际测试频率处于同一数量级。由于实测电路寄生参数如串联电阻、电容等的影响,仿真结果与测试结果稍有出入。 相似文献
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Stock J. Malindretos J. Indlekofer K.M. Pottgens M. Forster A. Luth H. 《Electron Devices, IEEE Transactions on》2001,48(6):1028-1032
A vertical resonant tunneling transistor (VRTT) has been developed, its properties and its application in digital logic circuits based on the monostable-bistable transition logic element (MOBILE) principle are described. The device consists of a small mesa resonant tunneling diode (RTD) in the GaAs/AlAs material system surrounded by a Schottky gate. We obtain low peak voltages using InGaAs in the quantum well and the devices show an excellent peak current control by means of an applied gate voltage. A self latching inverter circuit has been fabricated using two VRTTs and the switching functionality was demonstrated at low frequencies 相似文献
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A. Alemu 《Microelectronics Journal》2009,40(3):421-423
Stunning theoretical efficiencies have been predicted for quantum-confined solar cells. However, practical realizations remain inefficient as these devices suffer from an inherent difficulty in the extraction of photo-generated carriers from the confined states. Leveraging on the shallow valence band offset of dilute nitrides and using a carefully chosen material system and device design, we show the possibility of circumventing this problem by separating the optimization of the valence and conduction band and reducing the issue to a single particle problem. Band structure calculations including strain effects, band anti-crossing models and transfer matrix methods are used to theoretically demonstrate optimum conditions for enhanced vertical transport. High-electron tunneling escape probability, together with a free movement of quasi-3D holes, is predicted to result in enhanced PV device performance. Furthermore, the increase in electron effective mass due to the incorporation of N translates in enhanced absorptive properties, ideal for PV application. 相似文献
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介绍了典型的零电流转换ZCT(Zero Current Transition)PWM直流变换器的基本工作原理,分析了其存在的主开关电流应力大和辅开关硬关断的问题,提出了一种改进型开关电路。对其拓扑结构和工作原理进行了详细分析,设计了电路参数,并对其进行了Pspice仿真。结果证明此改进能够使辅助开关近似零电流关断,提高了变换器的性能。 相似文献
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Yi Wei 《Microelectronics Journal》2011,42(6):851-854
Resonant tunneling diodes (RTDs) are receiving much attention because of their high-speed switching capability and functional versatility. Due to the negative differential resistance exhibited by RTDs, great functionality with a single gate can be achieved. In this paper, novel universal threshold logic gates (UTLG) based on RTD with simple structure and fixed parameter are proposed. The three-variable UTLG implement all the threshold functions of three variables by reconfiguring the input bits. The proposed circuit can also be applied to the design of arbitrary logic function in a multilevel threshold network. Finally, the operation of UTLG is verified by HSPICE simulation using extensively validated models. 相似文献