Development of waveguide-type functional optical devices using semimagnetic semiconductor superlattices

本研究采用电离团束(ICB)沉积技术外延生长了半磁半导体Cd&lt；1-x&Gt；MnxTe薄膜，研究了薄膜的电子结构和光学、磁光、电学性质，为利用Cd&lt；1-x&Gt；MnxTe超晶格制作波导型光学器件奠定了基础。得到了以下结果：(1)X射线光电子能谱(XPS)结果表明，Cd_1-x&Gt；Mn_xTe的p-d杂化与Mn浓度x无关。XPS和磁圆二向色性(MCD)的结果表明，在高x区，塞曼分裂的高阶微扰计算是重要的。X=1(MnTe)的MnxTe薄膜，在基本上被视为局域态的3d多态之间的光学跃迁能下观察到光电流。从组态相互作用团簇模型来看，这可以用强p-d杂化的p-d电荷转移跃迁来解释，它在Cd_&lt；1-x&Gt；Mn_xTe的5p-Te轨道组成的价带中产生空穴。(3)我们尝试用ICB技术在Cd_&lt；1-x&Gt；Mn_xTe薄膜中掺杂In。结果表明，Cd&lt；1-x&Gt；MnxTe薄膜的电导率随In团簇电离百分数的增加而增大。随着In掺杂量的增加，薄膜的电导率先增大后减小，这是由于薄膜结晶质量的降低。而薄膜的电导率约为10~4OmeGAcm量级。这些结果需要对Cd_(1-x)&Gt；Mn_xTe薄膜的掺杂条件作进一步的研究。

In this study, epitaxial growth of semimagnetic semiconductor Cd_<1-x>Mn_xTe films was performed by the ionized-cluster beam (ICB) deposition technique and their electronic structure and optical, magneto-optical and electrical properties were investigated for a fundamental research of waveguide-type optical devices using Cd_<1-x>Mn_xTe superlattices. The following results were obtained.(1)From results of the x-ray photoelectron spectroscopy (XPS), it was found that the p-d hybridization of Cd_<1-x>Mn_xTe was independent of the Mn concentration x. The results of XPS and magneto-circular dichroism (MCD) suggest that a high-order pertubation calculation of the Zeeman splitting is important in the high x region.(2)For Cd_<1-x>Mn_xTe films with x=1 (MnTe), the photocurrent was observed at optical transition energies between 3d multiple states, which are substantially regarded as a local state. From the configuration interaction cluster model, this can be explained by the p-d charge transfer transition through the strong p-d hybridization, which generates holes in the valence band composed of 5p Te orbitals of Cd_<1-x>Mn_xTe.(3)We tried to dope Cd_<1-x>Mn_xTe films with In by the ICB technique. It was found that the electrical conductivity of Cd_<1-x>Mn_xTe films increases with increasing the ionization percentage of In clusters. As the doping amount of In increases, the electrical conductivity increases and then decreases due to degradation of the crystalline quality of films. However, the conductivities of films were of the order of 10^4OMEGAcm. These results required funther studies on the doping conditions of Cd_<1-x>Mn_xTe films.