双磁垒中电子的隧穿效应

采用平面波近似数值方法解非均匀磁场中电子的薛定谔方程,计算了在半导体异质结上沉积带状导电薄膜(通有电流)或I型超导材料产生的两种类型的双磁垒体系的电子隧道结构,以及相应的弹射(ballistic)电导,得知这两种体系的电子隧穿情形差异较大,而它们的电导结构却很相似.     

Novel Hyperbranched Phthalocyanine as a Hole Injection Nanolayer in Organic Light‐Emitting Diodes

A novel organic hyperbranched copper phthalocyanine was synthesized for use as a hole injection nanolayer on ITO in organic light‐emitting diodes (OLEDs). This material is soluble in organic solvents which allows for processing under anhydrous conditions, unlike water based conventional polymer hole injection layer materials such as poly(3,4‐ethylenedioxythiophene)(PEDOT)/polystyrene sulfonate (PSS). The hyperbranched layer increased the luminous efficiency and brightness of single layer OLED devices, in addition to reducing current leakage which causes crosstalk in panel devices, compared to devices prepared from PEDOT/PSS. Therefore, this material is more suitable for OLED applications due to its processing and performance advantages over conventional commercial conducting polymer compositions.

     

The Effect of Persistent TEMPO Radicals on the Gilch Polymerization

The mechanism of the Gilch polymerization leading to poly(p‐phenylene vinylenes) is still a matter of controversial discussion. Similar to some other research groups, we strongly favor a basically radical process. Moreover, we believe it is initiated by spontaneously formed diradicals. Here, we describe further experimental evidence which clearly supports the assumed initiation step: it is shown how the polymerization process is affected quantitatively when different amounts of 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (TEMPO) are added as a scavenger. In full agreement with our expectations, the chain growth is either retarded or completely prevented, depending on the respective molar ratio of monomer and scavenger.

     

Schottky barrier MOSFET structure with silicide source/drain on buried metal

In this paper, we propose a novel Schottky barrier MOSFET structure, in which the silicide source/drain is designed on the buried metal (SSDOM). The source/drain region consists of two layers of silicide materials. Two Schottky barriers are formed between the silicide layers and the silicon channel. In the device design, the top barrier is lower and the bottom is higher. The lower top contact barrier is to provide higher {on-state} current, and the higher bottom contact barrier to reduce the off-state current. To achieve this, ErSi is proposed for the top silicide and CoSi₂ for the bottom in the n-channel case. The 50~nm n-channel SSDOM is thus simulated to analyse the performance of the SSDOM device. In the simulations, the top contact barrier is 0.2e~V (for ErSi) and the bottom barrier is 0.6eV (for CoSi₂. Compared with the corresponding conventional Schottky barrier MOSFET structures (CSB), the high on-state current of the SSDOM is maintained, and the off-state current is efficiently reduced. Thus, the high drive ability (1.2mA/μm at V_ds=1V, V_gs=2V) and the high I_on/I_min ratio (10⁶) are both achieved by applying the SSDOM structure.     

Numerical studies of atmospheric pressure glow discharge controlled by a dielectric barrier between two coaxial electrodes

The glow discharge in pure helium at atmospheric pressure, controlled by a dielectric barrier between coaxial electrodes, is investigated based on a one-dimensional self-consistent fluid model. By solving the continuity equations for electrons, ions, and excited atoms, with the current conservation equation and the electric field profile, the time evolution of the discharge current, gas voltage and the surface density of charged particles on the dielectric barrier are calculated. The simulation results show that the peak values of the discharge current, gas voltage and electric field in the first half period are asymmetric to the second half. When the current reaches its positive or negative maximum, the electric field profile, and the electron and ion densities represent similar properties to the typical glow discharge at low pressures. Obviously there exist a cathode fall, a negative glow region, and a positive column. Effects of the barrier position in between the two coaxial electrodes and the discharge gap width on discharge current characteristics are also analysed. The result indicates that, in the case when the dielectric covering the outer electrode only, the gas is punctured earlier during the former half period and later during the latter half period than other cases, also the current peak value is higher, and the difference of pulse width between the two half periods is more obvious. On reducing the gap width, the multiple current pulse discharge happens.     

Potential energy surfaces of ozone in the ground state

Equilibrium parameters of ozone, such as equilibrium geometry structure parameters, force constants and dissociation energy are presented by CBS-Q {\it ab initio} calculations. The calculated equilibrium geometry structure parameters and energy are in agreement with the corresponding experimental values. The potential energy function of ozone with a C离解能;空气;能量表面;地面ozone, potential energy surface, barrier, dissociation energyProject supported by the National Natural Science Foundation of China (Grant Nos~10376021 and 10676025), and the Scientific Research Fund of Sichuan Provincial Education Department, China (Grant No~2006A131).2006-10-08Equilibrium parameters of ozone, such as equilibrium geometry structure parameters, force constants and dissociation energy are presented by CBS-Q ab initio calculations. The calculated equilibrium geometry structure parameters and energy are in agreement with the corresponding experimental values. The potential energy function of ozone with a C2v symmetry in the ground state is described by the simplified Sorbie-Murrell many-body expansion potential function according to the ozone molecule symmetry. The contour of bond stretching vibration potential of an O3 in the ground state, with a bond angle （θ） fixed, and the contour of O3 potential for O rotating around O1-O （R1）, with O1-O bond length taken as the one at equilibrium, are plotted. Moreover, the potentials are analysed.     

Simulation of multilayer Cu/Pd（100） heteroepitaxial growth by pulse laser deposition

The heteroepitaxial growth of multilayer Cu/Pd(100) thin film via pulse laser deposition (PLD) at room temperature is simulated by using kinetic Monte Carlo (KMC) method with realistic physical parameters. The effects of mass transport between interlayers, edge diffusion of adatoms along the islands and instantaneous deposition are considered in the simulation model. Emphasis is placed on revealing the details of multilayer Cu/Pd(100) thin film growth and estimating the Ehrlich--Schwoebel (ES) barrier. It is shown that the instantaneous deposition in the PLD growth gives rise to the layer-by-layer growth mode, persisting up to about 9 monolayers (ML) of Cu/Pd(100). The ES barriers of The heteroepitaxial growth of multilayer Cu/Pd（100） thin film via pulse laser deposition （PLD） at room temperature is simulated by using kinetic Monte Carlo （KMC） method with realistic physical parameters. The effects of mass transport between interlayers, edge diffusion of adatoms along the islands and instantaneous deposition are considered in the simulation model, Emphasis is placed on revealing the details of multilayer Cu/Pd（100） thin film growth and estimating the Ehrlich-Schwoebel （ES） barrier. It is shown that the instantaneous deposition in the PLD growth gives rise to the layer-by-layer growth mode, persisting up to about 9 monolayers （ML） of Cu/Pd（100）. The ES barriers of 0.08 ± 0.01 eV is estimated by comparing the KMC simulation results with the real scanning tunnelling microscopy （STM） measurements,     

电容耦合分区放电等离子体的研究

介绍了一种新的大气压下空气中等离子体产生方法─── 电容耦合分区放电。该方法综合了电晕放电和介质阻挡放电的优点,在大气压下可以生成大规模、高密度、均匀稳定的非平衡等离子体。其放电功率可达常规介质阻挡放电100倍以上,且可根据需要灵活调整。     

指数屏障期权定价模型

本文在股票价格服从几何布朗运动的假设下,采用一种简化的方法,推导了指数屏障期权定价公式。该方法具有一般性,能用来解决其它该类型的屏障期权的定价问题。     

有机电致发光空穴传输材料研究进展*

有机空穴传输材料的成膜性及其薄膜的热稳定性对于提高有机电致发光器件的效率和寿命具有重要的作用.本文按材料所含主体结构单元的不同,将有机空穴传输材料分为三类,从提高材料的成膜性及其热稳定性出发,详细介绍了近年来有机空穴传输材料的研究进展.