Magnetic properties and optical spin functionalities of atomically layer-controlled hybrid structures of semiconductors with magnetic materials

在本研究中，原子层控制的半导体与磁性材料的混合结构的制造。其目的是研究这些纳米结构中界面处的微观磁相互作用和磁光功能，并开发具有新的光学自旋功能的杂化纳米材料。获得了以下结果。(1)ZnCdSe量子威尔斯外延生长的反铁磁MnSe原子层的磁性δ掺杂。研究了这种原子层控超薄膜的磁自旋，并阐明了其与激子的相关性。(2)采用电子束光刻技术制备了ZnCdMnSe量子威尔斯与Co线的混合纳米结构。由于Co中的铁磁自旋波和Mn离子的自旋翻转，观察到光散射。结果，在这种磁性混合纳米结构中，来自Co的局部有效磁场分布被量化。(3)将非磁性半导体ZnCdSe和磁性半导体ZnCdMnSe量子威尔斯耦合，制备了磁性非对称双量子威尔斯阱，并利用圆偏振时间分辨光致发光技术研究了磁场中激子自旋动力学.据观察，II型转变是由依赖于自旋的磁场引起的。这实现了新的光学自旋功能，以在空间上分离空穴自旋。(4)采用电子束光刻技术制备了磁性半导体ZnCdMnSe量子威尔斯与磁性Co/Pt多层膜的混合纳米盘结构。它成功地控制激子自旋态的半导体纳米盘的垂直Co磁化产生的本地垂直磁场。(5)在具有隧道势垒的磁性半导体ZnCdMnSe量子威尔斯阱与CdSe量子点自组装的混合量子纳米结构中，发展了一种光学自旋功能。

In this research, atomically layer-controlled hybrid structures of semiconductors with magnetic materials are fabricated. It has aimed to research microscopic magnetic interactions at the interfaces and magneto-optical functionalities in these nanostructures, and to develop hybrid nano-materials exhibiting new optical spin functionalities. The following results are obtained.(1) ZnCdSe quantum wells were epitaxially grown with magnetic delta-doping of antiferromagnetic MnSe atomic layers. The magnetic spins of such an atomically layer-controlled ultra-thin film were studied and the correlation with excitons was clarified.(2) Hybrid nanostructures of ZnCdMnSe quantum wells with Co wires were developed by electron-beam lithography. Light scattering were observed due to the ferromagnetic spin waves in Co and the spin flip of the Mn ion. As a result, the local effective magnetic-field-distribution from the Co was quantified in such a magnetic hybrid nanostructure.(3) Magnetic asymmetric double quantum wells were fabricated, where non-magnetic semiconductor ZnCdSe and magnetic semiconductor ZnCdMnSe quantum wells were coupled, and the excitonic spin dynamics was studied by circularly polarized time-resolved PL in magnetic fields. It was observed that the type-II transition was induced by the magnetic field depending on the spin. This realizes a new optical spin functionality to separate spatially the hole spins.(4) Hybrid nano-disk structures of magnetic semiconductor ZnCdMnSe quantum wells with perpendicular magnetic Co/Pt multilayers were newly developed by an electron-beam lithography technique. It succeeded in the control of excitonic spin state in the semiconductor nano-disks by the local perpendicular magnetic fields generated from the perpendicular Co magnetization.(5) A optical spin functionality was developed in hybrid quantum nanostructures of CdSe Self-assembled quantum dots with magnetic semiconductor ZnCdMnSe quantum wells with tunnel barriers.