Nine-state resonant tunneling diode memory

The authors demonstrate an epitaxial series combination of eight pseudomorphic AlAs/In_0.53Ga_0.47As/InAs resonant tunneling diodes (RTDs) grown by molecular beam epitaxy on InP. This series RTD produces an eight-peak multiple negative differential resistance characteristic with a peak-to-valley current ratio (PVR) exceeding 2 per peak at a peak current density of approximately 6 kA/cm ². Hysteresis in the current-voltage characteristic is reduced by uniformly Si doping the double-barrier resonant tunneling region at a density of 5×10¹⁶ cm^-3. Using this multiple-peak RTD in series with a field-effect transistor load, a nine-state multivalued memory circuit is demonstrated     

Two-band combined model of a resonant tunneling diode

A two-band combined model of a resonant tunneling diode, based on the semiclassical and quantum mechanical (the wave function formalism) approaches is proposed. The main specific feature of this model is the possibility of taking into account the interaction between different classical or quantum mechanical device regions with simultaneous consideration of the Γ-X intervalley scattering. It is shown that this model gives satisfactory agreement with the experimental data on the current-voltage characteristics and allows explanation of the plateau region in these characteristics within the stationary model.     

共振隧穿二极管的设计和研制

用分子束外延在半绝缘砷化镓上生长两垒一阱结构,制成RTD单管。经过材料生长设计、工艺设计和版图设计几方面的改进,测得最高振荡频率已达54GHz。     

分集激光通信高速率半导体激光器驱动设计

为了实现高速率大气分集激光通信,研究并设计一种适用于高速率激光通信用驱动系统,对半导体激光器调制基本特性、频率稳定度和驱动阈值变化等特性进行了分析,通过实验验证了设计的性能。实验结果表明,系统在发射功率-3dBm,误码率小于10-6的情况下,半导体激光器频率长效稳定,驱动速率达到2.5Gb/s,基本满足大气激光通信的稳定度可靠、高速率和抗干扰等方面的要求。     

Microwave detection using the resonant tunneling diode

An experimental and theoretical study in the use of a resonant tunneling diode (RTD) as a microwave detector, based on its small-signal equivalent circuit model, is presented. It is shown that the rectified current from the diode can be accurately predicted and that the diode can be operated as a reactive microwave detector which absorbs no microwave power. For this detection mode, a matching network which maximizes the applied AC voltage can be used     

Pspice resonant tunneling diode models and application circuits

Using the analogue behavioural modelling capabilities of Pspice, the current–voltage characteristics and the large-signal equivalent circuit of a resonant tunneling diode are exploited to create a Pspice compatible model for the diode. The model is used, with very few other components, in the simulation of a number of circuit applications, including a sinusoidal wave generator, a frequency multiplier and three state logic circuits. The simulated circuit details, the related waveforms and three-state logic operations are described. The circuits are characterized mainly by their reduced complexity and ease of analysis.     

An improved multipeak resonant tunneling diode model for nine-stateresonant tunneling diode memory circuit simulation

A simple Spice equivalent circuit model for simulating current-voltage (I-V) characteristics and logic operation waveforms of an eight-peak resonant tunneling diode is presented. The simulated results agreed well with experimental data measured from an eight-peak resonant tunneling diode device fabricated by Seabaugh's experiment. This is shown through PSpice simulation     

Unified AC model for the resonant tunneling diode

A physics-based model is shown to yield the small-signal equivalent circuit of the resonant tunneling diode (RTD) including an analytic expression for both the quantum inductance and capacitance. This model unifies previous models by Brown et al. for quantum inductance and by Lake and Yang for quantum capacitance, and extends the RTD SPICE model of Broekaert. The equivalent circuit has been fit to both current-voltage and microwave S-parameter measurements of AlAs-InGaAs-InAs-InGaAs-AlAs RTDs from 45 MHz to 30 GHz and over biases from 0 to 0.81 V. Good agreement between the model and measurement is shown.     

A triple-well resonant tunneling diode for multiple-valued logicapplication

A resonant tunneling diode with four potential barriers and three quantum wells was fabricated and applied to multiple-valued logic. The diode exhibited significant double negative resistance characteristics and operated as a triple stable device with a single voltage between 180 and 230 K     

倍增型共振隧穿弱光探测器的噪声性能研究

对倍增型共振隧穿弱光探测器(RTDPD,resonant tunneling diode as photodetector)的噪声性能 进行研究。设计了具有倍增区的RTDPD结构。对探测器电流-电压(I-V) 特性的模拟发现,加入倍增区 以后探测器的光电流和暗电流均被放大,其峰值电流增大了1.7倍。 对RTDPD的噪声分布模拟发 现,1/f噪声比散粒噪声和热噪声高出10 个数量级左右。对倍增 区的电场强度和过剩噪声因子进行了模拟, 并计算了过剩噪声的功率谱密度。分析了倍增型RTDPD的总噪声,并对有、无倍增区时RTDPD 的噪声等 效功率进行了计算。结果显示,倍增区引入的噪声不仅不会影响探测器有效信号的提取,而 且提高了探测器响应弱光的能力。     

太赫兹共振隧穿二极管探测器研究进展及应用

太赫兹波独特的性质使其在物理学、生物学、医疗诊断、无损检测、无线通信等领域有着广阔的应用前景。共振隧穿二极管(RTD)是一种基于量子隧穿效应的半导体器件,利用其负微分电阻和直流非线性特性,可以分别实现太赫兹波的产生和探测,近年来获得越来越多的关注。基于RTD的太赫兹探测器具有可室温工作、体积小、易集成、灵敏度高等特点,使其在未来短距离、超高速的太赫兹无线通信及万物互联等场景具备优势。本文将重点介绍太赫兹RTD探测器的研究进展及其应用进展,并对后续技术发展进行展望。     

Design of nanopipelined adder based on resonant tunneling diode

Due to the negative differential resistance exhibited by resonant tunneling diode (RTD), RTD is suited to implement the threshold gates and increases the functionality of a single gate. Recently, multi-threshold threshold gates (MTTGs) and generalized threshold gates (GTGs) have been proposed, which extend the circuit applications of RTDs. In this paper, a new RTD full adder structure with three logic modules is proposed. Based on this structure, four different adders are built with the combination of different module circuits based on MTTG and GTG. From the simulation results, one of the proposed circuits with GTG structure, namely FA_GG, has the best performance, which reduces 27.7–45.9% power-delay product value in comparison with the previous designs.     

InP基共振隧穿二极管太赫兹振荡器的设计与实现

利用InP基共振隧穿二极管（RTD）和加载硅透镜的片上天线设计实现了超过1 THz的振荡器。采用Silvaco软件对RTD模型进行仿真研究,分析了不同发射区掺杂浓度、势垒层厚度、隔离层厚度以及势阱层厚度等对器件直流特性的影响规律。对研制的RTD器件直流特性测试显示：峰值电流密度Jp为359.2 kA/cm²,谷值电流密度Jv为135.8 kA/cm²,峰谷电流比PVCR为2.64,理论计算得到的器件最大射频输出功率和振荡频率（fmax）分别为1.71 mW和1.49 THz。利用透镜封装的形式对采用Bow-tie片上天线和RTD设计的太赫兹振荡器进行封装,测试得到振荡频率超过1 THz,输出功率为2.57μW,直流功耗为8.33 mW,是国内首次报道超过1 THz的振荡器。     

Proposal of an optical modulator based on resonant tunneling andintersubband transitions

We propose and analyze an optical modulator based on intersubband transitions. The absorption is modulated by modulating the carrier density in the ground state of a quantum well (QW). Electrons are injected resonantly into this subband from a QW reservoir subband through a single barrier. When the two states are tuned out of resonance, the electrons are rapidly evacuated by means of the optical field. A waveguide based on surface plasmons is assumed in order to have a high optical mode overlap. Calculations are performed for a cascaded structure with four periods, assuming InGaAs-InIAs QWs. The considered modulator structure operates at λ=6.0 μm and is RC limited to 27 GHz. An extinction ratio of 4 is obtained with a low applied voltage of 0.6 V. At larger applied voltages, the absorption is bistable. Absorption at shorter/longer wavelengths can be obtained by using materials with a larger/smaller conduction band offset. We also assess resonant tunneling from a 2-D electron gas reservoir into an array of quantum dots and compare it to the 2-D-2-D tunneling resonance     

Multibit resonant tunneling diode SRAM cell based on slew-rateaddressing

We propose and demonstrate a resonant-tunneling diode (RTD) based memory cell in which N bits are stored in a series combination of N RTDs without internal node contacts. The slew rate of an applied voltage signal determines the circuit switching dynamics and allows addressing of the bits. We verify slew rate dependent switching order of up to four series RTDs experimentally and through SPICE simulation incorporating a physics-based RTD model. The new addressing scheme allows N bits to be stored in a stack of N vertically integrated RTDs compared to log₂ (N) bits in previous demonstrations. We demonstrate a two-bit two-RTD static memory cell based on the new method     

Two-port noise and impedance measurements for two-terminal deviceswith a resonant tunneling diode example

A two-port technique is presented for determining the circuit elements and noise sources of the equivalent circuit of a two-terminal device at microwave frequencies. The two-terminal device is connected as a two-port so that intrinsic and parasitic circuit elements can be obtained from full two-port S-parameter measurements. This measurement does not require one of the two contacts to be grounded, which makes it particularly well suited for the characterization of integrated devices where parasitic elements become important and cannot be easily calculated. The noise of the device is measured by employing a noise-figure meter and the intrinsic noise is computed from the measured terminal noise. As an example, the impedance and noise elements of a resonant tunneling diode (RTD) are measured over frequency ranges of 2-8 and 2-4 GHz, respectively     

A Wigner function-based quantum ensemble Monte Carlo study of a resonant tunneling diode

We present results of resonant tunneling diode operation achieved from a particle-based quantum ensemble Monte Carlo (EMC) simulation that is based on the Wigner distribution function (WDF). Methods of including the Wigner potential into the EMC, to incorporate natural quantum phenomena, via a particle property we call the affinity are discussed. Dissipation is included via normal Monte Carlo procedures and the solution is coupled to a Poisson solver to achieve fully selfconsistent results.     

A multiple-state memory cell based on the resonant tunneling diode

The device consists primarily of several molecular-beam-epitaxy (MBE-) grown GaAs/(AlGa)As resonant tunneling diodes connected in parallel. This device exhibits multiple peaks in the I-V characteristic. When a load resistor is connected, the circuit can be operated in a multiple stable mode. With this concept, implementation of three-state and four-state memory cells are made. In the three-state case the operating points at voltages V₀=0.27 V , V₁=0.42 V, and V₂=0.53 V represent the logic levels 0, 1, and 2. Similarly for the four-state memory cell the logic levels voltages are V₀=0.35 V, V₁=0.42 V, V₂=0.54 V, and V ₃=0.59 V. A suggestion of an integrated device structure using this concept is also presented     

Optical control of resonant tunneling diode monolithically integrated with PIN photodiode

Optical control of the resonant tunneling characteristics of an integrated optoelectronic device with a monolithic integrated double-barrier/PIN structure is studied. Optical switching of the bistable resonant tunneling state and optical injection locking of a resonant tunneling oscillator at 1 GHz are demonstrated.     

基于共振光隧穿效应的加速度传感器

为了设计新型的加速度传感器，将共振光隧穿结构应用于传感元件，利用COMSOL软件对传感器的频率响应、灵敏度性能等关键要素进行了模拟仿真分析，搭建了实验平台，验证了共振光隧穿原理。结果表明，基于共振光隧穿效应结构的加速传感器在100Hz~3000Hz范围内、加速度为500m/s2的情况下，灵敏度可达到6.7dB/g。该传感器小巧轻便、结构简单，且具有较高的灵敏度，这为光学传感器的研究提供了新的方法和思路，具有广阔的应用前景。