Modeling and simulation of silicon neuron-to-ISFET junction

Modeling and simulation of the silicon neuron-to-ISFET junction is presented. The neuronal electrical activity, extracellularly recorded by the ISFET, was simulated as a function of the neuro-electronic junction parameters such as the seal resistance, double-layer capacitance, and general adhesion conditions. This goal was achieved with a configuration consisting of “silicon neurons” i.e., assemblies of CMOS circuits that mimic the generation of the equivalents of the ionic currents and of the action potentials of real (biological) neurons; “silicon synapses” whose performances simulate those of their biological counterpart; depletion-mode MOSFET-based ISFETs that simulate the signal recording devices; passive component-based circuits that model the neuro-electronic junction. The models of the neuron, synapse, coupling interface, and ISFET were implemented in HSPICE and used to simulate the behavior of the junction between stimulated neurons (described by the compartmental model) and ISFETs.     

隐与现——论色彩交界现象的视觉意义及对平面广告的影响

广告中色彩交界产生的融合或闪烁现象可以直接影响受众的视注意点,根据视注意点的不同,得出一个结论:交界融合的色彩适合应用在含有大量信息的印刷平面广告当中,而交界闪烁的色彩适合应用在户外广告中。     

由等价掺杂转换理论得到非对称线性缓变P-N结的击穿特性

基于等价掺杂转换理论的应用,得到了解析计算非对称线性缓变P-N结击穿特性.由于非对称线性缓变P-N结是单扩散P-N结的一个恰当近似,因而,研究其击穿特性可以更好地理解和设计功率器件P-N结的终端结构.运用等价掺杂转换方法的基本理论得到了不同扩散掺杂梯度和衬底浓度组合系列的击穿电压.研究了最大耗尽层宽度在扩散侧和衬底侧的扩展,给出了它们随扩散掺杂梯度和衬底浓度组合的变化而出现的不同特点.本方法预言的最大击穿电压较之单纯的突变结和对称线性缓变P-N结更接近文献报道的结果,显示了等价掺杂转换理论的理论计算非对称线性缓变P-N结击穿电压的有效性.     

Computer modelling of current matching in a-Si : H/a-Si : H tandem solar cells on textured TCO substrates

Computer modelling is used as a tool for optimising a-Si : H/a-Si : H tandem cells on textured substrate in order to achieve current matching between the top and bottom cell. To take light scattering at the textured interfaces of the cell into account, we developed a multirough-interface optical model which was used for calculating the absorption profiles in the tandem cells. In order to simulate multi-junction solar cell as a complete device we implemented a novel model for tunnel/recombination junction (TRJ), which combines the trap-assisted tunnelling and enhanced carrier transport in the high-field region of the TRJ.We investigated the influence of light scattering and thickness of the intrinsic layer of the bottom cell on the optimal ratio i2/i1 between the thicknesses of the bottom (i2) and top (i1) intrinsic layers in the current-matched cell. The simulation results show that increasing amount of scattering at the textured interfaces leads to a lower ratio i2/i1 in the current-matched cell. This ratio depends on the thickness of the intrinsic layer of the bottom cell. The simulation results demonstrate that a-Si : H/a-Si : H tandem cell with 300 nm thick intrinsic layer in the bottom cell exhibits higher efficiency than the cell with 500 nm thick bottom intrinsic layer.     

Issues on the chalcopyrite/defect-chalcopyrite junction model for high-efficiency Cu(In,Ga)Se2 solar cells

Considering the chalcopyrite/defect-chalcopyrite junction model for Cu(In_1−xGa_x)Se₂-based devices and our previously reported findings for the Cu(In_1−xGa_x)₃Se₅ defect chalcopyrites, we have postulated that uniform high-Ga-content photovoltaic structures (with x > 0.35) do not yield acceptable device performance due to the electrical and structural differences between both types of materials (chalcopyrite and defect-chalcopyrite).In this contribution, the structural properties of the surface region of Ga containing absorber materials have been studied by grazing incidence X-ray diffraction. We find that there are significant differences between surface and bulk. A structural model is proposed for the growth of the chalcopyrite/defect-chalcopyrite junction relative to its Ga content. And we demonstrate that closely lattice matched high-Ga-content structures (x > 0.35) can produce solar cells withv acceptable performances. The high-voltage and low-current electrical outputs from high Ga structures are very desirable in module fabrication because overall resistive losses can be substantially reduced.     

冷发射电子束掺杂磷

一种新的冷发射电子束掺杂方法已研究成功。这种方法可实现高浓度(C_(max)=2.8×10~(20)/cm~3),超浅结[(x_j)_(min)≤0.1μm],而且损伤比离子注入的小得多。用这种方法制备的太阳能电池控制器件性能很好。     

Operation of NIST Josephson Array Voltage Standards

This paper begins with a brief discussion of the physical principles and history of Josephson effect voltage standards. The main body of the paper deals with the practical details of the array design, cryoprobe construction, bias source requirements, adjustment of the system for optimum performance, calibration algorithms, and an assessment of error sources for the NIST-developed Josephson array standard.     

碳化硅结势垒肖特基二极管的质子辐射效应

碳化硅结势垒肖特基二极管(SiC JBS)是新一代航天器电推进系统的关键部件,但高能粒子辐射严重威胁其可靠性与稳定性。为揭示其辐射损伤机理,为其抗辐射加固设计与考核评估储备数据,本研究基于加速器开展了先进商用SiC JBS 10~20 MeV中能质子地面辐照实验,并提取器件辐照前后的正向伏安特性、反向伏安特性、电容电压等电学参数及缺陷特性。系统分析器件关键特性随辐照条件的改变规律。结果显示,质子辐照引起了器件肖特基势垒升高、载流子浓度降低,且10 MeV较低能质子导致的位移损伤退化更严重。分析认为,PN结界面缺陷导致高性能商用SiC JBS反向电学性能对中能质子的辐照更加敏感,正向特性相对稳定,辐照生碳缺陷造成载流子去除效应是引起SiC JBS性能退化的主要机制。     

Optimum heating of pressure components of steam boilers with regard to thermal stresses

A method for determining time–optimum fluid temperature changes is presented. In contrast to current standards, stepwise fluid temperature changes are allowed. The optimum fluid temperature changes are assumed in the form of a simple time function. It is possible to increase the fluid temperature stepwise, and then the fluid temperature can be increased with a constant rate at the beginning of the heating process. The permissible rates of the fluid temperature change determined by the proposed method are smaller than those obtained by boiler standards. But, due to the abrupt increase in fluid temperature, the heating time of a thick-walled component is of the same order as in the case of calculations according to EN 12952-3 European Standard. However, the total circumferential stresses on the edge of the hole do not exceed the allowable value.     

SiNx烧穿工艺下硅太阳电池结构研究

介绍了在全国产设备构成的中试线上开展的高效单晶硅太阳电池研究工作,并制备出了最高转换效率达15.7%的单体电池(面积103×103mm2).实验采用PECVD方法制备SiNx减反、钝化薄膜,并采用正背面电极一次金属化烧结技术,同时完成氮化硅薄膜烧穿工艺.实验还研究了PECVD硅烷与氨气流量比对SiNx钝化、光学和保护性质的影响.分析了氮化硅薄膜及简化新工艺与提高太阳电池效率的关系.实验最后采用化学染色法测量了太阳电池的p-n结结深,结果表明该太阳电池的p-n结为0.25 μm的浅结,直接证明了SiNx薄膜对p-n结有良好的保护作用.