共查询到17条相似文献,搜索用时 62 毫秒
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大多数氧化物光折变晶体研究都没有考虑外加直流 电场的影响。通过Kukhtarev 材料方程得出施加直流电场时光折变晶体双波混频空间电荷场的材料方程,对比研究无外加 电场和施加电场的情况下,归一化空间电荷场随归一化输入光强、归一化扩散场、中性施主 与受主陷阱浓度比以及归一化外加直流电场的变化趋势;分析外加直流电场对增益系数的提 升作用及其影响因素。结果表明:归一化扩散场较低时,施加直流电场可显著提升空间电荷 场,有外加直流电场的空间电荷场明显高于无外加直流电场的空间电荷场。但是在归一化扩 散场较高时,这种现象则不明显,此时空间电荷场受施加直流电场的影响较小;另外,当施 加直流电场时,增益系数增加更多,并且在20-27 dBm/cm2的最佳 光强范围内达到饱和值。同 时,最佳入射光强对应的峰值 增益随着外加直流电场的增加而增大。所得结果可为光折变晶 体双波混频的实际应用提供理论指导。 相似文献
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光折变晶体中ps激光脉冲二波耦合增益正负转换现象 总被引:2,自引:0,他引:2
用二列脉宽为60ps的连续锁模Nd:YAG激光的倍频光在掺Ce的KNSBN晶体中进行二波耦合.当泵浦光脉冲迟于信号光脉冲到达晶体,或泵浦光脉冲虽先于信号光脉冲到达晶体.但时间提前量小于激光脉冲半高宽时.信号光的二波耦合平均增益是非负的;当泵浦光脉冲先于信号光脉冲到达晶体且时间提前量大于激光脉冲半高宽时.信号光的二波耦合平均增益可变为负的.对此给出物理解释. 相似文献
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本文讨论了Orotron的大讯号计算中空间电荷的影响。首先推导出直角坐标系统中,当一个边界为无限大时的空间电荷场的近似表达式,然后利用这一空间电荷场模型,计算了Orotron的自洽的大信号相互作用,讨论了空间电荷参量对器件性能的影响。 相似文献
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本研究采用近红外光谱法和低温测量技术,获得了EL2能级的心内跃迁特征光谱和包括6个小峰的精细结构。探讨了心内跃迁与横向声学(TA)声子的耦合机理,系统观察了它的光猝灭效应,提出亚稳态模型,得出了由10K升温过程EL2能级近红外吸收与温度的依赖关系,确定了115K为亚稳态恢复至稳态的最低温度转变点。由实验结果提供的EL2能级内部结构的信息,提出EL2能级的理论模型。 相似文献
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在建立的理论模型基础之上,定量地分析了EL2能级对GaAs MESFET夹断电压的影响,指出位于本征费米能级以下的EL2能级是影响GaAs MESFET夹断电压大小的主要因素,EL2能级对GaAs MESFET夹断电压的影响程度与EL2能给的缺陷密度呈线性关系。 相似文献
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带状电子注具有非轴对称性和大宽高比的特性,为了研究其空间电荷效应,本文建立了相应的二维宏粒子物理模型,并通过格林函数法求解带状电子注内的空间电荷力。在该模型中,带状电子注用一系列窄带代替,每个窄带受到的空间电荷力通过叠加其它窄带作用于该窄带的电场力得到。本文对该窄带模型进行了详细的分析,计算了电子注内的空间电荷力,编写了基于该模型的数值模拟程序,模拟了带状电子注在不同静电磁约束下的运动及传输情况,计算结果与三维PIC 软件有很好的一致性,验证了基于该二维宏粒子模型的格林函数法求解带状电子注空间电荷场的合理性和准确性。 相似文献
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《Lightwave Technology, Journal of》2005,23(6):2175-2185
A theoretical model to numerically study the local space-charge field induced by light in a photorefractive crystal biased with two independent, perpendicularly oriented external static fields is introduced. This model appears attractive because it allows varying, in the crystal transverse plane, of the orientation of the external biasing static field with respect to that of the optical-field vector, then enhancing the tensorial properties of the crystal. The numerical analysis has revealed that, in a nonconventional biasing configuration, the spatial distributions of the space-charge-field vector transversal components exhibit a further anisotropy that has not been shown up to now. Nevertheless, from a practical point of view, such a boundary configuration could allow better management of the focusing characteristics of the material. 相似文献
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旁栅效应是制约GaAs集成电路性能和集成度的有害寄生效应。本文研究了MESFET电路的旁栅效应的光敏特性和迟滞现象 ,认为这两个现象可能与衬底深能级 (如EL2 )有密切的关系 ,通过减小衬底杂质补偿度有可能减轻旁栅效应影响。 相似文献
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A rigorous formulation of capacitance changes during trap filling processes is presented and used to accurately determine
the electron capture cross section of EL2 in GaAs at a particular temperature, 377K, in this case. The value, σn (377K) = 2.7 × 10−16 cm2, is compared with that predicted from the emission dependence. 相似文献
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The quenching of the photocurrent and photo-Hall effect of several undoped semi-insulating gallium arsenide samples has been
measured and compared with the deep-level photoluminescence spectra from neighboring samples. Samples that show either EL2
(0.68 eV) or ELO (0.63 eV) photoluminescence have distinctly different photocurrent quenching behaviors. EL2 samples show
a photocurrent decrease of several orders of magnitude, and a change fromn-type to p-type conduction during quenching at 80 K with 1.1 eV light. ELO samples show a reduction in photocurrent of less
than an order of magnitude with no change in the carrier type at this temperature. Photo-Hall effect experiments at 80 K indicate
that the conduction isn-type for the ELO samples, but changes fromn- to p-type during the quench for the EL2 samples. The temperature dependence of the quenching has also been studied. EL2
samples show little variation in the range 10-80 K, while ELO samples show significant quenching similar to EL2 after the
temperature is reduced below 70 K. These results indicate that defects other than EL2 can significantly affect photocurrent
quenching experiments. 相似文献
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比较了掺In和非掺杂LEC-GaAs晶体中的EL2缺陷,分析了掺In量的不同与热处理过程的不同对LEC-GaAs晶体中EL2缺陷的影响。 相似文献
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M. E. Sherwin J. C. Zolper A. G. Baca T. J. Drummond R. J. Shul A. J. Howard D. J. Rieger R. P. Schneider J. F. Klem 《Journal of Electronic Materials》1994,23(8):809-818
Zinc and magnesium implants into GaAs were profiled with secondary ion mass spectroscopy and etching capacitance-voltage to
measure the as-implanted and annealed profiles for the eventual formation of shallow p+/n junction gates for junction field effect transistors (JFETs). The larger mass of the zinc ions results in shorter projected
range with significantly less tailing than magnesium implants. High dose, shallow zinc implants annealed under tungsten gate
metal showed good activation with negligible diffusion. The improved profile of the zinc implant, as compared to a similar
magnesium implant, allowed a tighter JFET design with increased performance. Zn gated n-channel enhancement mode GaAs JFETs
with 0.9 μm gate lengths showed transconductances up to 200 mS/ mm with a ft of 18 GHZ and a fmax of 37 GHz. The performance of these self-aligned fully implanted JFETs compare favorably with comparably sized implanted
MESFETs. 相似文献