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41.
By the aid of temperature- and magnetic-field-dependent Hall effect measurements, we have extracted the multi-carrier transport information in N-doped and N–In codoped p- ZnO thin films grown on Si substrates through mobility spectrum analysis. It is found that owing to the compensation between free electrons and holes, the two-dimensional hole gas from ZnO/Si interface layers becomes determinant and results in the high p-type conductivity and high hole mobility in the ZnO samples. Compared with N-doping, the N–In codoping introduces many In donors and increases acceptor incorporation, as well as enhancing the free hole mobility due to the short-range dipole-like scattering. 相似文献
42.
研制了基于SOS的胡杨200和胡杨700脉冲功率源。给出了胡杨200和胡杨700的电路原理、组成结构和实验波形。介绍了在SOS脉冲功率源上开展的高重复频率强流电子束产生、长寿命阴极实验、绝缘介质的高重复频率击穿实验和低引导磁场无箔二极管等实验研究进展。经测试,胡杨200在2 kHz重复频率、负载阻抗200 Ω下,输出电压200 kV,脉冲宽度约35 ns,平均输出功率大于10 kW;在300 Hz条件下可连续运行。胡杨700同样为全固态脉冲功率源,其设计指标:输出电压700 kV,电流5 kA,脉冲宽度约40 ns;经初步调试在150 Ω电阻负载上单脉冲输出指标达到660 kV,4.4 kA,脉宽约70 ns。 相似文献
43.
This paper reviews a microscopic model of basic electron-hole pair excitation processes in strongly confined semiconductor quantum dots (QD) and their influence on the optical QD properties. The effects of valence band mixing, Coulomb interaction, and surface polarization are taken into account. The exciton and biexciton wave functions and energies are obtained using a numerical diagonalization method. The computed optical spectra, such as absorption, gain, pump-probe, and two-photon absorption, agree well with experiments. 相似文献
44.
J. Grenzer A. A. Ignatov E. Schomburg K. F. Renk D. G. Pavel'ev Yu. Koschurinov B. Melzer S. Ivanov S. Schaposchnikov P. S. Kop'ev 《Annalen der Physik》1995,507(3):184-190
We report on a microwave oscillator based on Bloch oscillations of electrons in a semiconductor superlattice. Our GaAs/AlAs superlattice, at room temperature, was coupled electromagnetically by an antenna to a rectangular cavity resonator, and was operated at a current-voltage state of negative differential conductance. We observed generation of microwave radiation at frequencies, depending on the resonator length, between 7 and 30 GHz. Electronic tuning by several percent was possible; the ratio of linewidth to frequency was of the order of 10?4. A radiation power up to 1 μW (at 10 GHz) was obtained, corresponding to a generator efficiency of the order of 10?3 for the conversion of electrical power to microwave radiation. 相似文献
45.
用分子束外延方法在GaAs(100)衬底上生长了Zn1-xMgxSySe1-y四元半导体合金薄膜.用X-射线衍射方法确定了外延层的结构和晶格常数.测量了这些样品在平行和垂直两种不同几何配置下的拉曼散射光谱并对其特性做了研究。从实验上观察到了四类不同的晶格振动模:类ZnSe的TO和LO模以及类ZnS和类MgS的LO模,实验发现:在ZnSe和ZnSSe中加入Mg使得类ZnSe的TO和LO模的振动频率下降;同时,也使类ZnS模的频率随S的增加率减小。 相似文献
46.
以单周期信号为例,数值模拟并讨论了注入频率和注入光场波动强度对主从式半导体激光器同步性能的影响。分别通过直接调制和外部调制两种方式获得单周期信号,并采用改进的参数——相似指数评价系统的同步性能。研究结果表明:当注入强度足够大时,系统实现注入锁定同步,外部调制的相似指数大于内部调制;注入强度恒定时,同步品质几乎不受调制指数的影响,而受调制频率的影响;由于内部、外部调制引起主激光器的输出反相,两种调制方式下同步品质随调制频率的变化趋势也相反。 相似文献
47.
Kameron Rausch N. Yurt D. F. Geraghty N. Eradat N. Peyghambarian Alan R. Kost 《Optical and Quantum Electronics》2007,39(7):611-622
Broadband arrayed waveguide gratings on InP are presented using a novel S-shape design. This design was utilized to accommodate
the large free spectral range required for broadband operation. Four and eight channel AWGs with a wavelength channel spacing
of 18 nm are discussed. The output peaks of the AWGs have a wide FWHM of 11 nm which provides insensitive operation to polarization,
temperature fluctuations, and chromatic dispersion. 相似文献
48.
在原单脉冲直线感应加速器(LIA)组元的基础上,利用电缆延时和电缆反射两种方式获得了间隔500~1 000 ns的猝发双脉冲输出。在感应加速腔上进行了双脉冲实验,获得了幅度大于200 kV、前沿小于35 ns、平顶大于60 ns的双脉冲加速电压波形。两种方式中第一个脉冲的前沿和幅度都达到了原单脉冲组元的水平,表明加速腔负载的变化对波形没有明显影响,但由于电缆对波形的损耗,第二个脉冲的幅度和前沿比第一个脉冲略差。可以利用水介质传输线来代替长电缆,减小传输线的长度及其对波形的损耗。两个脉冲间的幅度差异可以通过改变长电缆的阻抗来调节。实验表明,通过这两种猝发双脉冲的产生方式并结合加速腔磁芯的改进,可简单高效地完成原单脉冲LIA的双脉冲改造。 相似文献
49.
50.
L. Wu S. Zhu Y. Ni 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(2):349-354
Combination of two basic types of synchronization, anticipatory
synchronization and lagged synchronization, is investigated
numerically between two coupled semiconductor lasers. It is found
that lagged synchronization produced by a backward coupling with a
suitable delay can combine with the originally hidden anticipatory
synchronization and produce a type of synchronization overcoming the
original lagged synchronization produced by a forward coupling. We
study the combination synchronization phenomenon when the delay of
the backward coupling is different from that of the original
anticipatory synchronization. Our results suggest that the
synchronization combination phenomenon might allow an interpretation
of an experimental observation by Sivaprakasam et al. [Phys.
Rev. Lett. 87, 154101 (2001)] that the anticipating time is
irrespective of the external-cavity round trip time, which to date remains to be understood. 相似文献