An Optimal Information Hiding Approach Based on Pixel Value Differencing and Modulus Function

Wireless Personal Communications - This paper introduces the use of rhombus shaped dipole nanoantenna coupled to geometric diode in energy harvesting at 19.4 THz. An...     

Modelling of electroluminescent GaP diodes I (V) and L (V) characteristics

An investigation of the diode characteristics has been under taken in order to identify the physical mechanisms governing its behaviour at different bias levels. The influence of the various physical and technological parameters upon the electrical and optical behaviour of the component have been illustrated.A complete theoretical simulation of a GaP diode is presented and the principal results are examined. An analytical model of the devices operation, based on the physical analysis of the behaviour of the GaP diodes at all bias levels, is given. A method for determining the parameters (lifetimes) which govern the operation of the diode is described, followed by the presentation of the experimental results obtained from various GaP diodes.     

a-Si TFT/PIN图像传感器件

在模拟计算以a-Si TFT为有源开关,以a-Si PIN为光敏源的有源成像器件工作特性与各单元元件关系的基础上,详细讨论了单元器件的材料、物理参数对a-Si TFT/PIN耦合对特性的影响,并给出一定试验结果．用LED光源照射a-Si PIN的光电转换率可达18.1nA/lx,a-Si TFT/PIN有较好的线性度.     

Single barrier varactors for submillimeter wave power generation

Theoretical work on single barrier varactor (SBV) diodes indicates that the efficiency of a tripler with a SBV diode has a maximum for a considerably smaller capacitance variation than previously thought. SBV diodes based on GaAs, InGaAs and InAs have been fabricated and their DC properties have been tested. Detailed modeling of the carrier transport properties of the SBV device is carried out in two steps. First, the semiconductor transport equations are solved simultaneously, using a finite difference scheme in one dimension. Second, the calculated I -V and C-V characteristics are used by a multiplier simulator to calculate the optimum impedances and output powers at the frequencies of interest. The authors have developed an analysis technique which complements the harmonic balance technique. Simulations for a case study of a 750-GHz multiplier show that InAs diodes perform favorably compared to GaAs diodes     

Current voltage modeling of current limiting mechanisms in HgCdTe focal plane array photodetectors

An automated iterative nonlinear fitting program has been developed to model current-voltage (I–V) data measured on HgCdTe infrared (IR) detector diodes. This model includes the ideal diode diffusion, generation-recombination, band-to-band tunneling, trap-assisted tunneling (TAT), and avalanche breakdown as potential current limiting mechanisms in an IR detector diode. The modeling presented herein allows one to easily distinguish, and more importantly to quantitatively compare, the amount of influence each current limiting mechanism has on various detectors’ I–V characteristics. Longer cutoff wavelength detectors often exhibit significant current limitations due to tunneling processes. The temperature dependence of these tunneling characteristics is thoroughly investigated for two diodes.     

A software tool for the design of high power PiN diodes based on the numerical study of the reverse characteristics

A physically based model of power PiN diodes was developed to simulate the reverse voltage behavior with purpose of design optimization for specific application. The model includes process simulation and 2D drift-diffusion simulation of the defined geometrical diode structure. The process simulation was adjusted to obtain the same doping profile measured on a known sample. Since bulk silicon and dopants used in high power device production are different from those used in VLSI, various analytical models of impurity diffusion phenomena were considered and parameters calibration was carried out within the range found in the literature to obtain the best fit with measurements. Impact ionization coefficients of the reverse biased diode model were tuned by comparison with measurements on a reference device and exploited to study the dependence of breakdown voltage vs. various technological parameters.A simulation campaign for many different diode structures was conducted.An ad hoc interpolation algorithm was developed and applied for using measurement and simulation results in quick design of diode structures for specific application.     

A theoretical study on field emission array for microsensors

The authors present results on the analysis of two generic cone-shaped and wedge-shaped emitter-array diodes. The effects of the variations in device geometrical structure on the potential distribution, electric field, and emission current are discussed. The main geometric design parameters considered are the tip-to-collector distance, the emitter tip radius of curvature, and the intertip spacing. Pressure sensors based on these diode structures with one electrode fabricated on a pressure sensitive thin diaphragm were studied. The analysis shows that a cone-shaped emitter array has a larger emission current per emitter tip, but the wedge-shaped array has better pressure sensitivity     

a-SiTFT/PIN图像传感器件

在模拟计算以 a- Si TFT为有源开关 ,以 a- Si PIN为光敏源的有源成像器件工作特性与各单元元件关系的基础上 ,详细讨论了单元器件的材料、物理参数对 a- Si TFT/PIN耦合对特性的影响 ,并给出一定试验结果 .用 L ED光源照射 a- Si PIN的光电转换率可达 18.1n A/lx,a- Si TFT/PIN有较好的线性度     

Characteristics of a GaN-based Gunn diode for THz signal generation

A generalized large-signal computer simulation program for a Gunn oscillator has been developed.The properties of a Gunn diode oscillator based on the widely explored GaN,are investigated using the dev...     

恒磁场对Si、Ge基二极管I-V特性的影响及机理分析

在恒磁场为0～2T的范围内,对Si、Ge基二极管的反向饱和电流和正向电流进行了测试.结果表明,在一定的电学条件下,随着磁感应强度B的增大,磁场对Ge基二极管的反向饱和电流的影响比Si基二极管的更明显.磁场对Si基二极管的正向特性几乎没有影响,但可以观测到Ge基二极管的正向电流随磁场的增强发生了变化.依据半导体理论基础,对实验结果进行了分析并通过建立理论模型对磁场中二极管的I-V特性进行了模拟.     

Simulation and measurement of quasi-optical multipliers

The lumped-element finite-difference time-domain method is used to analyze quasi-optical multipliers based on diode loaded slot antennas. The method is validated firstly for a passive microstrip-fed structure then for the diode loaded case in both small- and large-signal regimes. The diode model is separately validated using a series diode mounted on a microstrip line. Input return loss and radiation patterns show good agreement with measurements and the concept of effective conversion loss is introduced and results show reasonable agreement between measurement and simulation. A new diode arrangement is introduced where dual offset diodes are placed in the slot instead of the conventional central diode. The diode position can then act as an extra design parameter. The performance of the two structures has been compared; currently best performance is still obtained for the central-diode structure. Finally, a fully quasi-optical structure is simulated with plane-wave excitation. Central and dual-diode structures are again compared and the diode position and input plane-wave field strengths are optimized. Slot voltage distributions, radiation patterns, and effective quasi-optical conversion losses are presented     

Modeling high-speed optical transmission systems

Computer simulation of a 2.5-Gb/s intensity-modulated/direct-detected optical system with high path dispersion is described. This simulation, based on single-mode laser diode rate equations, includes transmit and receiver circuit filtering, receiver circuit noise, avalanche photodiode noise, fiber dispersion, and laser chirp. The rate equations are sufficiently general to model mode-offset distributed feedback laser diodes. The system power penalty, due to laser chirp and fiber dispersion, is calculated using Gaussian quadrature numerical integration. By simulating a population of some 12800 laser diodes and correlating the performance of each laser in a transmission system with its spectral characteristics, it is possible to deduce laser specifications that will assure satisfactory operation in long-span links. These results are used to study a laser diode specification under consideration by CCITT, and, by studying the simulated laser line shapes, some modifications to the CCITT specification are considered     

Analysis of GaAs tunnel diode oscillators

GaAs tunnel diode oscillators are analyzed using a tenth-order power series approximation of the current-voltage characteristics of the diodes. The analysis yields significantly better agreement between measured and calculated power outputs than previous analyses which were based on a cubic approximation of the current-voltage characteristics.     

二极管型非制冷红外焦平面中二极管结构优化研究

为适应非制冷红外探测器高空间分辨率的发展趋势,非制冷红外焦平面阵列作为非制冷红外探测器的核心部件不断向大阵列、小像素方向发展。本文针对二极管型非制冷红外焦平面阵列,理论分析了敏感元件二极管对读出电路以及器件性能的影响,在确定二极管最佳工作电流的同时,提炼出二极管结构中串联个数以及结面积为主要性能影响因素。基于此,设计了p+n-pn-n+p三合一二极管,并将其与传统二极管、回型二极管、p+n-n+p二合一二极管、以及由p+n-n+p二合一二极管直接拓展得到的两种三合一二极管进行了对比考察,研究发现6种结构中p+n-pn-n+p三合一二极管在相同尺寸下拥有最多的二极管串联数量且结面积相对最大;进而利用Sentaurus TCAD仿真,验证了在同一整体尺寸下,p+n-pn-n+p三合一二极管的电压温度系数分别约为p+n-n+p二合一二极管,及在其基础上直接拓展得到的两种三合一二极管的1.5倍,为回型二极管与传统二极管的2.6倍、3.7倍。证明了在小像素下p+n-pn-n+p三合一二极管性能最优,且在其基础上拓展可得到N合一二极管能进一步优化器件的性能。     

Organic doped diode rectifier based on parylene-electronic beam lithogrpahy process for radio frequency applications

We have adapted a “peel-off” process to structure stacked organic semiconductors (conducting polymers or small molecules) and metal layers for diode microfabrication. The fabricated devices are organic diode rectifier in a coplanar waveguide structure. Unlike conventional lithographic process, this technique does not lead to destroy organic active layers since it does not involve harsh developer or any non-orthogonal solvent that alter the functionality of subsequentially deposited materials.This process also involves recently reported materials, as a p-dopant of an organometallic electron-acceptor Copper (II) trifluoromethanesulfonate, that play the role of hole injection layer in order to enhance the performances of the diode.Comparatively to self-assembled monolayers based optimized structures, the fabricated diodes show higher reproducibility and stability. High rectification ratio for realized pentacene and poly (3-hexylthiophene) diodes up to 10⁶ has been achieved. Their high frequency response has been evaluated by performing theoretical simulations. The results predict operating frequencies of 200 MHz and 50 MHz for pentacene and P3HT diode rectifiers respectively, with an input oscillating voltage of 2 V peak-to-peak, promising for RFID device applications or for GSM band energy harvesting in low-cost IoT objects.     

An Improved Physics-Based Formulation of the Microwave p-i-n Diode Impedance

An improved formulation of the frequency-dependent impedance for p-i-n diodes from physical and geometrical parameters is presented. This work is addressed to diode designers and allows them to evaluate quickly and accurately the diode impedance. It comes in parallel with existing SPICE p-i-n diode model used in CAD software. Under forward bias conditions, important recombinations occur in the heavily doped end regions of thin p-i-n diodes that seriously affects the diode impedance. This effect is taken into account to increase the accuracy of existing numerical models and to extend their validity domain to any I-region thicknesses. This improvement has been validated by measurement results on a 5-mum I-region width silicon p-i-n diode     

基于肖特基势垒二极管三维电磁模型的220GHz三倍频器

采用阻性肖特基势垒二极管UMS DBES105a设计了一个太赫兹三倍频器.为了提高功率容量和倍频效率,该倍频器采用反向并联二极管对结构实现平衡式倍频.根据S参数测试曲线建立了该二极管的等效电路模型并提取了模型参数.由于在太赫兹频段二极管的封装影响到电路的场分布,将传统的二极管SPICE参数直接应用于太赫兹频段的电路设计存在一定缺陷,因此还建立了二极管的三维电磁模型.基于该模型研制出的220 GHz三倍频器最大输出功率为1.7 mW,最小倍频损耗为17.5 dB,在223.5 GHz~237 GHz输出频率范围内,倍频损耗小于22 dB.     

6毫米波段(40～60GHz)砷化镓体效应二极管

通过对体效应二极管在毫米波高端工作特点的分析,详细讨论了6毫米GaAs体效应管的设计原则.着重探讨了器件设计中热参数与微波寄生参数要求间的矛盾,推导得到一组计算公式用以确定器件管芯与封装的设计参数.介绍了采用GaAs/AsCl_3/H_2汽相n~#外延、无氰无铵电镀金热沉、双金带十字引线等措施的器件制备工艺.研制的二极管在V波段的最大输出功率达130mW,最高效率为3.8%;以谐波方式在94GHz下输出大于10mW.本文还重点报道了器件可靠性研究的情况,器件预期的室温平均工作寿命超过1.4×10~8小时.使用该器件的振荡器已成功地用于常温50°K低噪声参放及微波遥感等方面.     

Potentials of GaP as millimeter wave IMPATT diode with reference to Si, GaAs and GaN

This paper presents the simulation results of DC,small-signal and noise properties of GaP based Double Drift Region( DDR) Impact Avalanche Transit Time( IMPATT) diodes. In simulation study we have considered the flat DDR structures of IMPATT diode based on GaP,GaAs,Si and GaN( wurtzite,wz) material. The diodes are designed to operate at the millimeter window frequencies of 94 GHz and 220 GHz. The simulation results of these diodes reveal GaP is a promising material for IMPATT applications based on DDR structure with high break down voltage( V_B) as compared to Si and GaAs IMPATTs. It is also encouraging to worth note GaP base IMPATT diode shows a better output power density of 4. 9 × 10~9 W/m~2 as compared to Si and GaAs based IMPATT diode. But IMPATT diode based on GaN( wz) displays large values of break down voltage,efficiency and power density as compared to Si,GaAs and GaP IMPATTs.