Growth and magneto-optical properties of quantum structures with sub-nanometer magnetic semiconductor wirers

用<1-x>分子束外延技术在GaAs（001）衬底上生长了Zn_ Mn_xSe异质外延层，Mn组分x=0 ~ 0.2。用X射线衍射法测量了生长层的晶格应变。异质外延层部分弛豫。激子PL峰能量被校正为由于晶格应变引起的能隙偏移，并且在无应变条件下的峰能量作为Mn组分的函数而获得。测量了B=0-2 T时荧光光谱和反射光谱随磁场的变化。在反射光谱中观察到了与重空穴和轻空穴有关的跃迁，并且与晶格应变的预测结果一致。生长了Zn_<0.91>Cd_<0.09>Se/Zn_<0.82>Mn_<0.18>Se超晶格，阱层厚度为4- 35，势垒层厚度为12。磁光致发光（MPL）的测量在法拉第几何。采用Kronig-Penny模型分析了超晶格中激子发射的塞曼位移随阱层厚度的变化，其中导带和价带偏移受外磁场调制.考虑了ZnMnSe在界面处的顺磁性增强和Mn在异质界面处的扩散。Mn的扩散对超晶格系统的塞曼位移有重要影响。测量了ZnSe/ZnCdSe/ZnSe单量子阱中ZnMnSe线的MPL。磁场垂直于金属丝时的塞曼位移大于磁场平行于金属丝时的塞曼位移。

Zn_<1-x>Mn_xSe hetero epitaxial layers were grown on GaAs (001) substrates by MBE for Mn composition x=0-0.2. Lattice strain in the grown layer was measured by X-ray diffractiom. The heteroepitaxial layers were partially relaxed. Excitonic PL peak energy was corrected for the energy gap shift due to the lattice strain, and the peak energy in the strain free condition was obtained as a function of Mn composition. Magnetic field dependences of PL and reflection spectra were measured for B=0-2 T. Heavy hole related and light hole related transitions were observed in the reflection spectra, and the heavy and light hole splitting was in agreement with that expected from the lattice strain. Zn_<0.91>Cd_<0.09>Se/Zn_<0.82>Mn_<0.18> Se superlattices were grown with well layer thickness of 4-35A and barrier layer thickness of 12 A. Magneto-photoluminescence(MPL) was measured in the Faraday geometry. The Zeeman shifts of the excitonic emissions from the superlattices were analyzed as a function of well layer thickness by using Kronig-Penny model, in which the conduction and valence band offsets were modulated by external magnetic field. Paramagnetism enhancement of ZnMnSe at the interface with nonmagnetic layer and Mn diffusion at the heterointerface were taken into consideration. The Mn diffusion showed a crucial effect on the Zeeman shift of the superlattice system. MPL of ZnSe/ZnCdSe/ZnSe single quantum well with ZnMnSe wires in ZnCdSe well was measured. Zeeman shift with magnetic field perpendicular to wires was found to be larger than that with magnetic field parallel to wires.