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，以创建基于垂直腔表面发射激光器（VCSEL）的干草叉分叉双稳态操作和自旋极化电子注入的新型非线性光学功能器件。（1）我们研究了具有方形波导的 VCSEL 中存在两个正交偏振模式。自饱和系数和交叉饱和系数的相对大小对于确定激光二极管偏振切换的特性至关重要。数值计算证实自饱和系数和交叉饱和系数之间的关系满足阻挡层和量子阱有源层的极化双稳态条件。压应变量子阱在更宽的区域内满足双稳态传导，特别是在线性增益较大的区域。(2)全光信号处理，如具有信号位宽转换功能的解复用以及RZ与RZ之间的转换。 NRZ 格式使用偏振双稳态 VCSEL 进行了实验演示。我们通过模拟表明，使用此类 VCSEL 可以获得 3R 功能（重定时、重塑和再生）。(3) 我们根据时间和极化估计了漂移通过 p-n 结的电子的自旋弛豫时间。解决了光致发光问题。结果表明，在漂移过程中偏振度保持得相当好。(4)我们制作了带有由铁磁金属CoCr制成的n侧电极的发光二极管(LED)。然而，LED 的光输出是非偏振的。该结果指出极化电子可能在GaAs和CoCr之间的界面处去极化。