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81.
ZENG Zhaoquan WANG Yong DU Xiaolong MEI Zengxia KONG Xianghe JIA Jinfeng XUE Qikun & ZHANG Ze . State Key Laboratory for Surface Physics Institute of Physics Chinese Academy of Sciences Beijing China . Laboratory of Electron Microscopy Institute of Physics Chinese Academy of Sciences Beijing China . College of Physics Engineering Qufu Normal University Qufu China . Beijing University of Technology Beijing China 《中国科学G辑(英文版)》2004,47(5):612-620
ZnO is a wide direct bandgap (Eg=3.37 eV at room temperature) II-VI compound semiconductor of wurtzite structure (a = 3.249 ? c = 5.207 ?. Compared to GaN and ZnS, ZnO has a larger exciton binding energy, ~60 meV (cf. ~25 meV for GaN and ~40 meV for ZnS), which is advantageous to realizing low-threshold excitonic lasers. Since optically pumped UV lasing of ZnO at room temperature was reported in 1997[1], much attention has been paid to the crystal quality improvement and p-type conduc… 相似文献
82.
Mid-infrared generation based on a periodically poled LiNbO3 optical parametric oscillator 下载免费PDF全文
We report a nanosecond Nd:YVO_4-pumped optical parametric oscillator (OPO) based on periodically poled LiNbO_3 (PPLN). Tuning is achieved in this experiment by varying the temperature and period of the PPLN. The design of double-pass singly resonant oscillator (DSRO) and confocal cavity enables the OPO threshold to be lowered considerably, resulting in a simple, compact, all-solid-state configuration with the mid-infrared idler powers of up to 466mW at 3.41μm. 相似文献
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This paper performs a numerical simulation of concentric-ring discharge structures within the scope of a two-dimensional diffusion--drift model at atmospheric pressure between two parallel circular electrodes covered with thin dielectric layers. With a relative high frequency the discharge structures present different appearances of ring structures within different radii in time due to the evolvement of the filaments. The spontaneous electron density distributions help understanding the formation and development of self-organized discharge structures. During a cycle the electron avalanches are triggered by the electric field strengthened by the feeding voltage and the residual charged particles on the barrier surface deposited in the previous discharges. The accumulation of charges is shown to play a dominant role in the generation and annihilation of the discharge structures. Besides, the rings split and unify to bring and annihilate rings which form a new discharge structure. 相似文献
86.
本文采用基于密度泛函理论的第一性原理全势能线性缀加平面波方法(FLAPW),分析了Bi2Te3-xSex体系中各原子自旋轨道耦合(SOI)的p1/2修正对体系性质的影响,并对Bi2Te3-xSex(x≤3)同晶化合物的电子特性进行系统的理论研究,首次计算出Bi2S
关键词:
2Te3-xSex(x≤3)同晶化合物')" href="#">Bi2Te3-xSex(x≤3)同晶化合物
第一性原理
电子结构
自旋轨道耦合 相似文献
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Performance improvement of MEH-PPV:PCBM solar cells using bathocuproine and bathophenanthroline as the buffer layers 下载免费PDF全文
In this work, bathocuproine (BCP) and bathophenanthroline (Bphen), commonly used in small-molecule organic solar cells (OSCs), are adopted as the buffer layers to improve the performance of the polymer solar cells (PSCs) based on poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV): [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) bulk heterojunction. By inserting BCP or Bphen between the active layer and the top cathode, all the performance parameters are dramatically improved. The power conversion efficiency is increased by about 70% and 120% with 5-nm BCP and 12-nm Bphen layers, respectively, when compared with that of the devices without any buffer layer. The performance enhancement is attributed to BCP or Bphen (i) increasing the optical field, and hence the absorption in the active layer, (ii) effectively blocking the excitons generated in MEH-PPV from quenching at organic/aluminum (Al) interface due to the large band-gap of BCP or Bphen, which results in a significant reduction in series resistance (Rs), and (iii) preventing damage to the active layer during the metal deposition. Compared with the traditional device using LiF as the buffer layer, the BCP-based devices show a comparable efficiency, while the Bphen-based devices show a much larger efficiency. This is due to the higher electron mobility in Bphen than that in BCP, which facilitates the electron transport and extraction through the buffer layer to the cathode. 相似文献
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用时间分辨-傅里叶变换红外发射光谱研究了热的氢原子与C02分子间高效率的平动—振动(T—V)能传递.热的氢原子由ArF激光光解H2S得到,这种氢原子的平动能为223kJ/mo1。实验中观察到了从2130cm^-1到2400cm^-1的红外发射谱带,它归属于高振动激发的CO2分子的非对称伸缩振动(v3).对这一发射谱带的光谱拟合显示CO2的非对称伸缩振动被激发到了较高的振动态,振动量子数达到了v=7。并且有5580cm^-1的能量经传能过程由氢原子到达了CO2的v3模。实验条件下氢原子与C02的T—V传能效率为0.30。实验结果与Schatz等人的用3D半经典计算预测的碰撞截面符合的很好. 相似文献