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

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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.