Algorithms for automatic measurement of SIS-type hysteretic underdamped Josephson junction’s parameters by current-voltage characteristics

Some electrical parameters of the SIS-type hysteretic underdamped Josephson junction(JJ)can be measured by its current-voltage characteristics(IVCs).Currents and voltages at JJ are commensurate with the intrinsic noise level of measuring instruments.This leads to the need for multiple measurements with subsequent statistical processing.In this paper,the digital algorithms are proposed for the automatic measurement of the JJ parameters by IVC.These algorithms make it possible to implement multiple measurements and check these JJ parameters in an automatic mode with the required accuracy.The complete sufficient statistics are used to minimize the root-mean-square error of parameter measurement.A sequence of current pulses with slow rising and falling edges is used to drive JJ,and synchronous current and voltage readings at JJ are used to realize measurement algorithms.The algorithm performance is estimated through computer simulations.The significant advantage of the proposed algorithms is the independence from current source noise and intrinsic noise of current and voltage meters,as well as the simple implementation in automatic digital measuring systems.The proposed algorithms can be used to control JJ parameters during mass production of superconducting integrated circuits,which will improve the production efficiency and product quality.

The Nonideality Coefficient of Current-Voltage Characteristics for Asymmetric p-n-Junctions in a Microwave Field

It is shown that the nonideality coefficient m actually depends on the electron temperature Te, and the hole temperature Th. We get more general expression for the nonideality coefficient, taking into account the concentration of electrons and holes, as well as their temperature, coefficient and diffusion length, the temperature of the phonons, the applied voltage, and the height of the potential barrier.

Fabrication and characteristics of nitrogen-doped nanocrystalline diamond/p-type silicon heterojunction

Nitrogen-doped nanocrystalline diamond films(N-NDFs)have been deposited on p-type silicon(Si)by microwave plasma chemical vapor deposition.The reaction gases are methane,hydrogen,and nitrogen without the conventional argon(Ar).The N-NDFs were characterized by X-ray diffraction,Raman spectroscopy,and scanning electron microscopy.The grain sizes are of 8~10 nm in dimension.The N-NDF shows n-type behavior and the corresponding N-NDF/p-Si heterojunction diodes are realized with a high rectification ratio of 102 at^7.8 V,and the current density reaches to1.35 A/cm2 at forward voltage of 8.5 V.The findings suggest that fabricated by CH_4/H_2/N_2 without Ar,the N-NDFs and the related rectifying diodes are favorable for achieving high performance diamond-based optoelectronic devices.

Effect of Temperature on I-V Characteristic for ZnO/CuO

Research on nonmaterials has become increasingly popular because of their unique physical, chemical, optical and catalytic properties compared to their bulk counterparts. Therefore, many efforts have been made to synthesize multidimensional nanostructures for new and efficient nanodevices. Among those materials, zinc oxide (ZnO) has gained substantial attention owing to many outstanding properties. ZnO besides its wide band gap of 3.34 eV exhibits a relatively large excitons binding energy (60 meV) at room temperature which is attractive for optoelectronic applications. Likewise, cupric oxide (CuO) has a narrow band gap of 1.2 eV and a variety of chemo-physical properties that are attractive in many fields. Moreover, composite nanostructures of these two oxides (CuO/ZnO) may pave the way for various new applications. So in this thesis, eight samples of CuO/ZnO junction were synthesized and exposed to temperatures 60, 70, 80, 90, 100, 110, 120 and 130. The electrical properties of Schottky diode junctions were analyzed by I-V measurements under the influence of direct solar radiation and, lag of radiation (darkness) which shows the semi-logarithmic I-V characteristic curve of the fabricated photodiodes. Also energy band gap was estimated and the morphology and particle sizes of the as-prepared sample were determined by SEM. The SEM images of ZnO + CuO sample films were annealed at 60°C to 130°C step 10.

植物特征光谱测试系统研制及应用

以植物光合作用的基本原理和一种植物特征光谱实验方法的发明专利为依据,介绍以双驼峰光谱光源为基础,研制出能够产生覆盖光合有效辐射范围的多种单色光发生器,采用多种单色光发生器和光合作用测试仪组合构建植物特征光谱测试系统。阐述如何通过植物特征光谱测试系统获取植物单色光光合响应曲线、对应的饱和点曲线和补偿点曲线,并通过具体案例介绍该系统应用,为植物光照提供技术指导。

Biotechnical system based on fuzzy logic prediction for surgical risk classification using analysis of current-voltage characteristics of acupuncture points

Objective:This study aimed to develop expert fuzzy logic model to assist physicians in the prediction of postoperative complications of prostatic hyperplasia before surgery.Methods:A method for classification of surgical risks was developed.The effect of rotation of the current–voltage characteristics at biologically active points(acupuncture points)was used for the formation of classifier descriptors.The effect determined reversible and non-reversible changes in electrical resistance at acupuncture points with periodic exposure to a sawtooth probe current.Then,the developed method was tested on the prediction of the success of surgical treatment of benign prostatic hyperplasia.Results:Input descriptors were obtained from collected data including current-voltage characteristics of 5 acupuncture points and composed of 27 arrays feeding in the model.The maximum diagnostic sensitivity of the classifier for the success of a surgical operation in the control sample was 88%and for testing data set prediction accuracy was 97%.Conclusion:The use of tuples of current-voltage characteristic descriptors of acupuncture points in the classifiers could be used to predict the success of surgical treatment with satisfactory accuracy.The model can be a valuable tool to support physicians’diagnosis.

Nonlinear current-voltage characteristics originated from phase segregation and micro-cracks in polycrystalline La_(0.67)Ba_(0.33)MnO_3

Polycrystalline La0.67Ba0.33MnO3 bulk samples were annealed in flowing 95%Ar：5%H2 （AH） mixed gas at 973 K for different time respectively. The influence of the annealing time on the current-voltage properties was systematically investigated. Linear current-voltage characteristics were observed in the as-prepared and the 10 h annealed samples, and nonlinear current-voltage characteristics was found in the 100 h annealed sample. At the same time, segregation of impurity phase and micro-cracks were found on the surfaces of the 100 h annealed samples, which was testified to be Ba ion impurity. Analysis showed that the changes of electronic properties were caused by barium ion im-purities and micro-cracks in the 100 h annealed sample.

Current-voltage characteristics of light-emitting diodes under optical and electrical excitation

The factors influencing the current-voltage（I-V） characteristics of light-emitting diodes（LEDs） are investigated to reveal the connection of I-V characteristics under optical excitation and those under electrical excitation.By inspecting the I-V curves under optical and electrical excitation at identical injection current,it has been found that the I-V curves exhibit apparent differences in voltage values.Furthermore,the differences are found to originate from the junction temperatures in diverse excitation ways.Experimental results indicate that if the thermal effect of illuminating spot is depressed to an ignorable extent by using pulsed light,the junction temperature will hardly deflect from that under optical excitation,and then the I-V characteristics under two diverse excitation ways will be the same.

单晶硅电池对不同波长色光响应程度的研究

以氙灯为光源,经五种不同的滤色片进行滤光并对每一种光用光谱仪进行测定并与标准谱比对,然后分别照射在太阳能电池片上,通过调节氙灯的电源及光源与电池片之间的距离控制不同的光照强度,测量其开路电压、短路电流及最大输出功率.通过这些数据来计算太阳能电池的其他参数,并以波长为基础对每一种参数进行分析对比,得出了太阳能电池对这五种不同波长单色光的光电响应情况.结果表明波长为577nm的单色光响应情况最为显著,并且伴随着光强的增加,其效率增长速度也随之增加.

单色光电流-电压特性测试在碲化镉太阳电池研究中应用

针对不同结构的碲化镉(CdTe)太阳电池,测试其单色光特性,并计算出不同波长下的收集效率。结果表明,高质量的高阻层能提高太阳电池短波区的收集效率,对提高长波段的收集效率有一定作用;背接触层能够明显在电池背部形成欧姆接触;适当的硫化镉(CdS)层的厚度能够改善窗口层的界面,提升电池的器件性能。通过该测试方法可以获得器件结构与器件性能之间关系,从而为进一步优化电池结构和制备工艺、提高太阳电池转换效率提供依据。

A full-coupling model of PN junctions based on the global-domain carrier motions with inclusion of the two metal/semiconductor contacts at endpoints

A full-coupling model on the current-voltage(J-V)characteristics of PN junctions is put forward in the paper by taking into account both the whole junction and the two electrode regions consisting of metal/semiconductor(M/S)contacts.The depletion layer assumption proposed by the Shockley model is discarded.Gauss’law on the electric potential and the electric field is applied in the whole junction region such that the majority-carrier currents inside and outside the P/N barrier region are able to be exactly defined and clearly calculated.Then,the stable continuity equations of the electron and hole currents are established to show the current conversion between minority-and majority-carriers inside the whole PN junction region.By analyzing all the conversion procedure,the J-V characteristics of a PN junction are obtained with good agreement to the experimental results,which are closely dependent on the minority-carrier lifetime and doping concentrations.Obviously,the study on this topic possesses referential significance to mechanically tuning the performance of piezoelectric PN junctions and piezotronic devices.

Formation of Large-Volume High-Pressure Plasma in Triode-Configuration Discharge Devices

A ＂plane cathode micro-hollow anode discharge （PCHAD）＂ is studied in comparison with micro-hollow cathode discharge （MHCD）. A new triode-configuration discharge device is also designed for large-volume, high-pressure glow discharges plasma without glow-to-arc transitions, as well as with an anode metal needle, and a cathode of PCHAD. It has a ＂needle-hole＂ sustained glow discharge. Its discharge circuit employs only one power supply circuit with a variable resistor. The discharge experiments have been carried out in the air. The electrical properties and the photoimages in PCHAD, multi-PCHAD and ＂needle-hole＂ sustained discharge have been investigated. The electrical and the optical measurements show that this triode-configuration discharge device can operate stably at high-pressure, in parallel without individual ballasting resistance. And the electron density of the plasma is estimated to be up to 10^12cm^-3. Compared with the twosupply circuit system, this electrode configuration is very simple with lower cost in generating large-volume plasma at high pressures.

Dynamics of vortex–antivortex pair in a superconducting thin strip with narrow slits

In the framework of phenomenological time-dependent Ginzburg-Landau（TDGL） formalism,the dynamical properties of vortex-antivortex（V-Av） pair in a superconductor film with a narrow slit was studied.The slit position and length can have a great impact not only on the vortex dynamical behavior but also the current-voltage（Ⅰ-Ⅴ） characteristics of the sample.Kinematic vortex lines can be predominated by the location of the slit.In the range of relatively low applied currents for a constant weak magnetic field,kinematic vortex line appears at right or left side of the slit by turns periodically.We found such single-side kinematic vortex line cannot lead to a jump in the Ⅰ-Ⅴ curve.At higher applied currents the phase-slip lines can be observed at left and right sides of the slit simultaneously.The competition between the vortex created at the lateral edge of the sample and the V-Av pair in the slit will result in three distinctly different scenarios of vortex dynamics depending on slit length：the lateral vortex penetrates the sample to annihilate the antivortex in the slit;the V-Av pair in the slit are driven off and expelled laterally;both the lateral vortex and the slit antivortex are depinned and driven together to annihilation in the halfway.

Vortex pinning and rectification effect in a nanostructured superconducting film with a square array of antidot triplets

We study the stability of vortices pinning and dynamics in a superconducting thin strip containing a square array of antidot triplets by using the nonlinear Ginzburg–Landau（GL） theory. Compared with the regular square array of circular holes, the vortices are no longer pinned inside the circular holes, but instead stabilized at the center of the antidot triplets depending on the geometry parameters. Moreover, the influences of the geometry parameters and the polarity of the applied current on the current–voltage（I–V） characteristics are also studied. The critical current for the sample turning into a normal state becomes smaller when the hole diameter D is smaller and the spacing B between the holes is larger. Due to the asymmetric pinning sites, our numerical simulations demonstrate that the positive and negative rectified voltages appear alternately in the resistive state of the sample under an ac current of square pulses.

Phonon-dependent transport through a serially coupled double quantum dot system

Using Keldysh nonequilibrium Green function formalism and mapping a many-body electron-phonon interaction onto a one body problem, the electron transport through a serially coupled double quantum dot system is analyzed. The influence of the electron-phonon interaction, temperature, detuning, and interdot tunneling on the transmission coefficient and current is studied. Our results show that the electron-phonon interaction results in the appearance of the side peaks in the transmission coefficient, whose height is strongly dependent on the phonon temperature. We have also found that the inequality of the electron-phonon interaction strength in two dots gives rise to an asymmetry in the current-voltage characteristic. In addition, the temperature difference between the phonon and electron subsystems results in the reduction of the saturated current and the destruction of the step-like behavior of the current. It is also observed that the detuning can improve the magnitude of the current by compensating the mismatch of the quantum dots energy levels induced by the electron-phonon interaction.

Influence of Deformation on CVC p-n-Junction in a Strong Microwave Field

This paper investigates the current-voltage characteristics (CVC) strain of p-n-junction in a strong microwave (MW) field and shows that the deformation increases the current generated in the p-n-junction. We analyze the current-voltage characteristics of p-n-junction in which three-dimensional space (I,U,e) gives more complete information than the two-dimensional.

单色光波长对硅晶太阳能电池特性的影响

为了提高硅晶太阳能电池的转换效率,研究了单色光波长对硅晶太阳能电池表征参数的影响.采用太阳能光伏实验设备,恒定功率的氙灯作为模拟光源,测量在不同波长的入射光作用下3种硅晶太阳能电池表征参数变化.结果表明,入射光波长900 nm左右时,单晶硅太阳能电池开路电压、短路电流以及光谱灵敏度值最大;570 nm左右时,非晶硅太阳能电池的光谱灵敏度值最大.该研究结果为提高太阳能电池的转换效率提供实验参考.

Analysis on electrical transport characteristic of 8-hydroquinoline aluminum film

The current_voltage and capacitance_voltage characteristic of the organic single_layered electroluminescent diode utilizing 8_hydroquinoline aluminum as active layer have been measured under bias ranging from -5 V to 28 V in this work. A simple model for charge transport process of 8_hydroquinoline aluminum layer is proposed to illuminate the conductivity characteristic of the diode.

石英晶体偏光干涉谱紫外区聚敛特性研究

采用连续偏光干涉原理,针对石英晶体样品,获得了石英晶体在300～800 nm间的光强透射比曲线和最大双折射率的色散曲线.通过改变出射缝隙的大小,光强透射比曲线极值的幅度随出射光缝隙的减小而变化并呈现一定的规律.缝隙较大时,在紫外区会出现光强最大、最小值聚敛的现象;缝隙大小只影响极值的幅度,并不影响极值对应的波长值;出射准单色光的波长范围是影响曲线变化的主要因素,材料吸收是次要因素.