Optical Spin Injection and Carrier Transport in Hybrid Nanostructures of Semiconductors and Magnetic Metals

半导体和磁性金属混合纳米结构中的光学自旋注入和载流子传输

• 批准号: 13450002
• 负责人: OKA Yasuo
• 金额: $ 8.83万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13450002/
• 关键词: spin injection; semiconductors; magnetic semiconductors; magnetic materials; spin electronics; nanostructures; lithography; photoluminescence

The objective of the research is following:1.Fabrication of hybrid nanostrctures of quantum wires, quantum dots and quantum wells, which are composed of II-VI compound diluted magnetic semiconductors and magnetic metals.2.Study of optical spin injection and spin transport in the hybrid nanostructures and application for spin electronic devices. For the above objective, we have fabricated the quantum nanostructures and hybrid nanostructures with CdTe, CdSe, ZnTe, ZuSe and magnetic materials of Mn and Co by using molecular expitaxy and electron beam lithography methods. Fabricated quantum and hybrid nanostructures are studied by femtosecond laser spectroscopy in high magnetic fields. Spin injection processes are investigated in CdTe-CdMnTe double quantum wells, where the transient photoluminescence of quantum-well excitons shows that spin injection and spin relaxation processes. Spin switching processes are clarified in ZnTe-ZnMnTe spin superlattices, where the distribution of up-and dow … More n-spin states of excitons is spatially separated in Zute and ZnMnTe layers by the external magnetic fields. The lowest spin state of excitons is modified from that of the ZnTe layer to that of the ZuMnTe due to the large Zeeman splitting of the exciton spins in the ZnMnTe layer. From the transient characteristics of the exciton photoluminescence, the reverse spin injection process (spin switching) is confirmed and the spin injection times are determined. Ultrafast spin dynamics of excitons is investigated in these diluted magnetic nanostructures by transient pump-probe spectroscopy. The spin dynamics in the high density electron-hole plasma, excitons, and Mn ions are clarified in the femotsecond to nanosecond time region. Fabrication of hybrid nanostructures is made by using electron beam lithography technique. The diluted magnetic quantum wells in the hybrid structures are affected by the magnetic field, which is induced by the ferromagnetic Co wires neighboring to the quantum wells. These phenomena have high possibilities for spin electronic applications. Less

本论文的主要研究内容如下：1.制备由II-VI族化合物稀磁半导体和磁性金属组成的量子线、量子点和量子威尔斯阱混合纳米结构; 2.研究混合纳米结构中的光自旋注入和自旋输运特性及其在自旋电子器件中的应用。为了实现上述目标，我们利用分子外延和电子束光刻技术制备了CdTe、CdSe、ZnTe、ZuSe以及磁性材料Mn和Co的量子纳米结构和混合纳米结构。利用飞秒激光光谱技术在强磁场中研究了量子纳米结构和混合纳米结构。研究了CdTe-CdMnTe双量子威尔斯阱中的自旋注入过程，量子阱激子的瞬态光致发光显示了自旋注入和自旋弛豫过程.研究了ZnTe-ZnMnTe自旋超晶格中的自旋开关过程， ...更多信息 在Zute和ZnMnTe层中，激子的n-自旋态被外部磁场空间分离。由于ZnMnTe层中激子自旋的大塞曼分裂，激子的最低自旋态从ZnTe层的最低自旋态修改为ZuMnTe的最低自旋态。从激子光致发光的瞬态特性，证实了反向自旋注入过程（自旋开关），并确定了自旋注入时间。利用瞬态泵浦-探测光谱研究了这些稀磁纳米结构中激子的超快自旋动力学。在高密度电子空穴等离子体，激子，和Mn离子的自旋动力学澄清在飞秒到纳秒的时间区域。利用电子束光刻技术制备了杂化纳米结构。混合结构中的稀磁量子威尔斯阱受到磁场的影响，磁场是由邻近量子威尔斯阱的铁磁Co线感应的。这些现象有很高的自旋电子应用的可能性。少

项目成果

S.Shirotori: "Magnetic-field-induced level crossing and the spin dynamics of excitons in Zn_<1-x>Mn_xTe/ZnTe quantum wells"J.Superconductivity, incorporating Novel Magnetism. 16. 457-460 (2003)

S.Shirotori：“磁场诱导的能级交叉和 Zn_<1-x>Mn_xTe/ZnTe 量子阱中激子的自旋动力学”J.超导，结合了新磁性。

H.Sakurai, K.Seo, Z.H.Chen, K.Kayanuma, T.Tomita, A.Murayama, Y.Oka: "Ultrafast exciton spin dynamics in Cd_<1-x>Mn_xTe quantum wells studied by transient pump-probe spectroscopy"Phys.Stat.Sol.(c). 241. 981-984 (2004)

H.Sakurai、K.Seo、Z.H.Chen、K.Kayanuma、T.Tomita、A.Murayama、Y.Oka：“通过瞬态泵浦探针光谱研究 Cd_<1-x>Mn_xTe 量子阱中的超快激子自旋动力学”

M.Nogaku, J.X.Shen, R.Pittini, T.Sato, Y.Oka: "transient-Level Crossing of Free and Bound Excitonic Magnetic Polarons in Cd_<1-x>Mn_xTe Single Crystals"Physical Review B. 63. 153314-1-153314-4 (2001)

M.Nogaku、J.X.Shen、R.Pittini、T.Sato、Y.Oka：“Cd_<1-x>Mn_xTe 单晶中自由和束缚激子磁极化子的瞬态能级交叉”物理评论 B.63.153314-

S.Shirotori: "Magnetic-field-induced level crossing end the spin dynamics of excitons in Zn_<1-x>Mn_xTe/ZnTe quantum wells"J. Superconductivity, incorporating Novel Magnetism. 16. 457-460 (2003)

S.Shirotori：“磁场诱导的能级交叉终止了 Zn_<1-x>Mn_xTe/ZnTe 量子阱中激子的自旋动力学”J。

Y.Oka, K.Kayanuma, S.Shirotori, A.Murayama, I.Souma, Z.H.Chen: "Excitonic Properties and Dynamics in Diluted Magnetic Semiconductor Quantum Nanostructures"Nonlinear Optics. 29. 491-499 (2002)

Y.Oka、K.Kayanuma、S.Shirotori、A.Murayama、I.Souma、Z.H.Chen：“稀磁半导体量子纳米结构中的激子性质和动力学”非线性光学。