A measurement technique and algorithm for determining the n-p-n and p-n-p alphas of a thyristor

A new method has been developed for accurately measuring the forward-blocking characteristics of gate-turnoff (GTO) thyristors, and for converting these characteristics into plots of n-p-n and p-n-p gain as a function of anode current and anode voltage. Specifically, anode current and gate current are measured as functions of gate-to-cathode voltage at a fixed anode voltage over several orders of magni, tude of anode current. These data are used to determine the electron and hole components of anode current, which are, in turn, used to calculate αnpnand αpnpover the entire range of anode current of interest. Examples are given that show how junction shorts, low minority-carrier lifetime in the n-base, and anomalously low n-p-n gain are diagnosed in GTO thyristors. These new procedures have successfully diagnosed the causes of gate insensitivity in 95 percent of the devices to which they have been applied.     

Improved efficiency of indium-tin-oxide-free organic light-emitting devices using PEDOT:PSS/graphene oxide composite anode

We have demonstrated an indium-tin-oxide free organic light-emitting device (OLED) with improved efficiency by doping poly (3,4-ethylene dioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) with graphene oxide (GO) as a composite anode. In comparison with a pure PEDOT:PSS anode, 55% enhancement in efficiency has been obtained for the OLEDs based on the PEDOT:PSS/GO composite anode at an optimal condition. The PEDOT:PSS/GO composite anode shows a lower hole-injection barrier, which contributes to the improved device efficiency. Moreover, both high transmittance and good surface morphology similar to that of the pure PEDOT:PSS film also contribute to the enhanced efficiency. It is obvious that composite anode will generally be applicable in organic optoelectronic devices which require smooth and transparent anode.     

GaAs planar-doped barrier vacuum microelectronic electron emitters

A novel vacuum microelectronic electron emitter has been demonstrated in GaAs by using a planar-doped-barrier (PDB) structure. Emitted electrons are collected in high vacuum by a tantalum anode placed ~1 mm away from the emitter surface. Surface passivation with (NH ₄)₂S_x followed by in situ heating in vacuum has been used to obtain an atomically clean surface. An emission current density of 0.42 A-cm^-2 and an efficiency of 0.3% have been obtained from a 60 μm×60 μm emission region with an anode bias of 100 V     

Electric-field control in planar Gunn-effect device with Schottky-barrier anode

The use of a Schottky-barrier anode contact has been proposed to improve the operating characteristics of a d.c.-biased planar Gunn-effect device. It has been confirmed experimentally that the high-field region appearing near the usual ohmic anode can be eliminated by using a Schottky-barrier anode.     

采用碳纳米管导电薄膜作为OLED的阳极

采用碳纳米管(CNT)替代ITO作为OLED阳极可以 解决ITO薄膜存在的可弯曲性能差,可靠性低等缺 点,使得柔性显示成为可能。本文采用混合型CNT导电薄膜作为阳极,探讨了CNT薄膜的制备 工艺、掺 杂方式及表面修饰等因素对绿光OLED性能的影响。实验结果表明,P型掺杂对CNT薄 膜的导电性能影响 有限;而PEDOT修饰层可以很好的提高CNT导电薄膜的平整度;此外,采用“十字交叉 ”的阳极形状有助于降低 阳极拐角处毛刺。通过优化器件各参数,制备的PET/CNTs/PEDOT/NPB/ALq₃/LiF/Al绿光OL ED发光效率达 到了195 cd/m²,结果表明采用混合型CNT作为OLED阳极是可行的。     

Life test studies on tungsten impregnated cathodes

NASA-Lewis Research Center has conducted an ongoing life test program on commercial impregnated tungsten cathodes since 1971. This brief is an update of the information as of December 1979. "B"-type cathodes, operated at 1100°C have been run in simulated microwave tubes at 2 A/cm²for more than four years with about 6- percent degradation in current at a constant reference anode voltage. "M'-type cathodes have been operated for 30 000 h at a cathode temperature of 1010°C and 2 A/cm²with no degradation in current at a constant reference anode voltage.     

基于MIC多晶硅薄膜阳极的微腔有机发光器件

通过对溶液法金属诱导晶化多晶硅薄膜制备工艺的优化,制备出性能良好的P型掺杂多晶硅薄膜。厚度为50nm的MICP+-Poly-Si薄膜的方块电阻可降低至400Ω左右,其光学特性表现为在红光区域具有比较高的反射率和很小的吸收率,因此用它替代ITO用作红光OLED的阳极材料。由于此薄膜对可见光比较高的反射率和阴极铝对可见光的高反射性,使之形成了一定Q值的微腔效应。结果显示该器件的最大流明效率为5.88cd/A,比用ITO作阳极制备的OLED提高了57%。进一步优化器件结构,调整发光层在腔中的最佳位置,可以大大增强发光强度,从而可以实现发光强度高、单色性好的红色微腔有机电致发光显示器件。     

Anode sputtering in high-voltage mercury arc valves

A method is described whereby the anode sputtering rate during recovery of a mercury arc valve can be estimated from its transient inverse current and voltage waveforms. Inverse currents have been measured in an experimental valve, from which corresponding anode sputtering rates are deduced for a variety of cathode coolant temperatures and commutation conditions. These measurements substantiate proposed methods of reducing anode sputtering in valves. The accuracy of the method has been confirmed by examining sputtered deposits found in an experimental valve after several hundred hours of rectifier operation. Major applications of this method are in the development and testing of valves for high-voltage direct current (hvdc) transmission. These include rapid assessment of the effect of design modifications on anode sputtering, and increasing the anode sputtering rate by a known factor through manipulation of the test conditions (e.g., cathode coolant temperature and dI/dt), thereby considerably shortening the time required for sputtering life tests. The latter application is particularly valuable in the case of single-gap valves where the effects of anode sputtering during recovery are likely to be the ultimate limitation on serviceable life. The saving in testing time is especially important because of the high operating cost of test plant at relevant levels, in our case 50 kV, 1000-ampere dc bridge rating.     

Artificial Soft–Rigid Protective Layer for Dendrite‐Free Lithium Metal Anode

Lithium (Li) metal has been pursued as “Holy Grail” among various anode materials due to its high specific capacity and the lowest reduction potential. However, uncontrolled growth of Li dendrites and extremely unstable interfaces during repeated Li plating/stripping ineluctably plague the practical applications of Li metal batteries. Herein, an artificial protective layer with synergistic soft–rigid feature is constructed on the Li metal anode to offer superior interfacial stability during long‐term cycles. By suppressing random Li deposition and the formation of isolated Li, such a protective layer enables a dendrite‐free morphology of Li metal anode and suppresses the depletion of Li metal and electrolyte. Additionally, sufficient ionic conductivity is guaranteed through the synergy between soft and rigid structural units that are uniformly dispersed in the layer. Dendrite‐free and dense Li deposition, as well as a greatly reduced interfacial resistance after cycling, is achieved owing to the stabilized interface, accounting for significantly prolonged cycle life of Li metal batteries. This work highlights the ability of synergistic organic/inorganic protective layer in stabilizing Li metal anode and provides fresh insights into the energy chemistry and mechanics of anode in a working battery.     

Lateral insulated-gate bipolar transistor (LIGBT) with a segmentedanode structure

A novel lateral insulated-gate bipolar transistor (LIGBT) structure, called the segmented anode LIGBT, is presented. In this structure, the anode, which is responsible for the injection of minority carriers for conductivity modulation, is implemented using segments of p ⁺ and n⁺ diffusions along the device width. This segmented design of the anode structure results in higher switching speed and reduction in device size. Depending on the value of the specific ON resistance, experimental results show that the segmented anode LIGBT has from 20% to 250% reduction in turn-off time as compared to the shorted anode LIGBT     

Voltage distributions in X-band n+-n-n+Gunn devices using a SEM

The SEM has been used as a voltage measuring probe to obtain voltage distributions in X-band n⁺-n-n⁺mesa structure Gunn devices. Dynamic distributions are obtained by operating the instrument in the stroboscopic mode. The results show accumulation layers in the oscillating device and the amplifier mode has a high field anode region.     

Barrier-controlled current conduction in field-controlled thyristors

An empirical analysis of the current conduction in field controlled thyristors under channel barrier height controlled current flow has been performed. This analysis shows that the device current increases exponentially with decreasing gate voltage and increases exponentially as the fifth root of the anode voltage. Based upon this analysis, an expression relating the blocking gain of these devices to the gate voltage and the anode current has been obtained.     

Production and investigation of TW proton beams from an annulardiode using strong radial magnetic insulation fields and a preformedanode plasma source

A magnetically insulated proton diode in extraction geometry which has achieved an ion beam power of 0.8 TW and an ion production efficiency of greater than 90% is described. Using a Pd-Ti metal hydride film on the anode surface and diverting part of the generator current through it with the help of plasma opening switches, a proton-rich plasma is preformed on the anode before any voltage occurs across the diode gap. Thus it is possible to apply very strong magnetic insulation, V_c/V_op>3. Ion current and diode voltage simultaneously reach a plateau for 40 ns, resulting in a nearly constant diode impedance for 60 ns. Thus, chromatic aberrations of the diode focusing system are minimized. The microscopic divergence of proton beamlets due to diode effects is determined to be 0.7°. Geometric aberrations of spherical and aspherical anode shape have been determined. The experimental results are compared to simulations with a 2.5 dimensional stationary PIC (particle-incell) code     

Low convergent confined-flow Pierce gun for a space TWT

An approach for designing an electron gun for a high efficiency, high linearity space traveling wave tube (TWT), has been presented. A low convergent (<10?:?1) Pierce electron gun of beam perveance 0.43?μP has been designed for a high gain, high linearity and high efficiency C-band 60?W Space TWT using in-house developed two-dimensional FDM based gun and collector simulation code PIERCE. In this gun, the first anode (isolated from the ground anode) has been kept nearly 100?V above the ground anode to act as an ion barrier for increasing cathode life and to regulate beam current over the lifetime of the tube. An M-type dispenser cathode of diameter 3.20?mm has been used for cathode loading of less than 1.0?A/cm² and heater wattage around 3.0?W. The magnetic focusing with integral-pole-piece barrel assembly and periodic-permanent magnets (PPM) have been designed using in house developed two-dimensional FDM based code SUNMAG. The practical problem of linking requisite cathode flux to the cathode for confined flow of the electron beam with low convergence factor has been sorted out by gradually increasing the PPM magnetic field. The magnetic field has been increased in steps from the gun and over the first five magnets varying from Brillouin field (B _B) value to twice B _B for achieving the electron beam with scalloping less than 10%. Agreements between the simulated results and the experimental results for the beam current and magnetic field profile have been achieved within 8%. The dynamic beam transmission (under rf operation of the tube) has been achieved better than 98% in the tube.     

柠檬酸盐对阳极箔形成速度与比电容的影响

为了提高铝电解电容器用高压阳极箔形成速度与比电容,将水合处理后的腐蚀箔在95℃、2 g/L柠檬酸钠去离子水溶液中浸泡5 min,在530 V电压化成时,形成时间缩短约2 min,化成箔比电容由0.556×10–6 F.cm–2提高至0.584×10–6 F.cm–2,阳极氧化铝膜的结构与性能得到改善。     

Low-voltage operation of the retarding-field oscillator at X band and in the millimeter wavelength region

This paper concerns the partial development of two low-voltage designs of the retarding-field oscillator. These designs differ fundamentally in their power coupling system. TheX-band model has coaxial-line coupling to a waveguide while the millimeter wavelength model has double-cavity coupling to a waveguide. The design developed atXband allows operation with the anode voltage as low as 200 volts and as high as 600 volts. Radio-frequency output power of 20 milliwatts at 200 volts and better than 1 watt at 600 volts is possible. In the millimeter wavelength range, three double-cavity designs have been investigated. These tubes operate in the range of from 4.30 to 5.20 mm, 5.00 to 6.4 mm, and 5.80 to 6.8 mm, respectively. All of these oscillators have anode potentials of 800 volts or less. An output power of 175 milliwatts has been obtained at a wavelength of 6.00 mm. A digest of characteristics possessed by important models of the retarding-field oscillator investigated as of November, 1957, also is included.     

Formation and study of thin-film lithium-ion batteries using CNT/silicon composite material as an anode

An approach to the formation of new composite material of the anode electrode for lithium-ion batteries composed of carbon nanotubes (CNTs) synthesized on a substrate coated with a silicon layer has been studied. The dependence of the cyclicity and specific capacity of such a material on the geometric parameters of a CNT array has been studied. Using a CNT/silicon composite, the battery prototypes have been assembled and their characteristics and behavior during prolonged storage have been studied.     

Bistable switching in a planar Gunn diode

This paper presents experimental and theoretical results showing that bistable switching, due to an anode-triggered trapped domain (TD), can be realized in a Gunn diode with an anode notch. The characteristics of the anode-triggered TD have been made clear by computer simulations. Bistable switching has been confirmed experimentally by using a planar Gunn diode with a groove, which was intentionally dug close to the anode.     

High conductive PEDOT via post-treatment by halobenzoic for high-efficiency ITO-free and transporting layer-free organic solar cells

The 4-halobenzoics (XBA) including 4-fluorobenzoic acid (FBA), 4-chlorobenzoic acid (CBA), 4-bromobenzoic acid (BBA) and 4-iodobenzoic acid (IBA) have been applied to modify poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) by simply spin-coating solvent treatment. A universal and significant improvement in the conductivity of PEDOT:PSS (from ∼1 S/cm to more than 3300 S/cm) has been achieved by XBA modification, which results from the acid XBA-induced phase segregation, depletion of PSS chains and the conformational change of the conductive PEDOT chains. Especially, the oxidation CBA treated PEDOT:PSS exhibits low sheet resistance of 43 Ω/sq and transparency of over 80% in the visible range, which are comparable to those of indium tin oxide (ITO). The modified PEDOT:PSS has been facilely applied as the transparent anode for high-efficiency ITO-free organic solar cell device without hole transport layer. The high power conversion efficiency of 7.9% has been achieved by employing CBA treated PEDOT:PSS as anode for ITO-free device based on poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b′]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)] (PTB7-Th):[6,6]-phenyl-C71 butyric acid methyl ester (PC₇₁BM), which is comparable to the corresponding devices based on the traditional ITO anode.     

非链式脉冲HF/DF激光的新型引发技术

为了发展一种引发脉冲HF/DF激光器的新型放电技术。采用均匀粗糙表面的阴极在注入能量密度高达200 J/L时仍可在激光介质中获得均匀稳定的体放电。优点是无需任何预电离,且对电极面型无特殊要求。针-盘电极实验表明,在非链式脉冲HF/DF激光介质中单通道放电表现为扩散均匀的辉光放电,板-板电极的体放电从粗糙阴极开始,阴极表面产生许多明亮的圆形亮点,每一个亮点随后形成一条向阳极扩散的通道,这些扩散的通道相互重叠形成了空间均匀的体放电。初步实验结果表明,采用这种技术可以实现高能、高重复频率的脉冲HF/DF激光输出。