Study of injection of spin - polarized electrons into semiconductors through ferromagnetic metal

自旋极化电子通过铁磁金属注入半导体的研究

基本信息

批准号：
11450023
负责人：
KAWAGUCHI Hitoshi
金额：
$ 9.47万
依托单位：
Yamagata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

We investigated mainly the following four topics to create new nonlinear optical functional devices based on the pitchfork bifurcation bistable operation of vertical-cavity surface-emitting lasers (VCSELs) and injection of spin-polarized electrons.(1) We studied the bistable switching between the two orthogonal polarization mode existing in the VCSEL with a squared shape waveguide. The relative magnitude of self- and cross-saturation coefficients are crucial to determine the characteristics of polarization switching of laser diodes. The numerical calculation confirmed that the relation between self- and cross saturation coefficients satisfies the condition for polarization bistability in both balk and quantum well active layers. The bistable conduction is satisfied in the wider region for a compressively strained quantum well, especially in the region with large linear gains.(2) All-optical signal processing, such as demultiplexing with a signal bit width conversion function and the conversion between RZ and NRZ formats, were experimentally demonstrated using a polarization bistable VCSEL. We have shown by our simulations that the 3R function (Retiming, Reshaping, and Regenerating) can be obtained using a such VCSEL.(3) We estimated the spin relaxation time of the electrons drifting through the p-n junction from the time- and polarization- resolved photoluminescence. The result showed that the polarization fairly maintained during the drift.(4) We fabricated the light emitting diode (LED) with an n-side electrode made of ferromagnetic metal, CoCr. However, the light output from LED was unpolarized. This result points out that the polarized electrons may be de-polarized at the interface between GaAs and CoCr.

我们主要研究了以下四个主题，以创建新的非线性光学功能设备，该设备基于干草叉分叉的垂直腔表面发射激光器（VCSELS）和自旋偏振电子的注入。自我和交叉饱和系数的相对大小对于确定激光二极管的极化转换的特征至关重要。数值计算证实，自我和交叉饱和系数之间的关系满足了Balk和量子活性层层的极化双重性的条件。在更宽的区域中，可满足压缩性应变的量子的良好孔，尤其是在线性较大增长的区域中满足。（2）使用极性辅助的VCSEL进行了实验证明的全光信号处理，例如具有信号宽度转换功能的全光信号处理，例如信号宽度转换函数以及RZ和NRZ格式之间的转换。我们通过模拟表明，可以使用这样的VCSEL获得3R函数（重新以重塑，重塑和再生）。（3）我们估计电子的自旋松弛时间从时间和极化 - 偏置 - 清除的光致发光。结果表明，在漂移期间公平维持的极化。（4）我们用铁磁金属制成的N边二极管（LED）制造了光发射二极管（LED）。但是，LED的光输出均未偏振。该结果指出，极化电子可以在GAAS和COCR之间的界面上去极偏振。