A study of electron and spin state of magnetic thin layer grown on negative electron affinity semiconductor

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We tried to investigate electron and spin state, and changing of Fermi level concerning to surface material (for example iron, nickel) and its thickness of ferro-magnetic layer (and/or multi layer), that are grown on semiconductor surface of negative electron affinity (NEA). At first we modified the pumping power of a MBE vacuum chamber by installing ion-pump, and then modified the sample manipulation system. After achieving a good vacuum condition we grew several types of samples with iron and/or Dy and its compound with gallium-arsenide. During the growth we monitored the surface condition with the reflection high electron energy diffraction (RHEED) and after the growth half of samples were checked the x-ray diffraction (XRD) and the transmission electron microscope (TEM). (A part of these work were published) For the rest of samples, we chose amorphous arsenic cap to keep the condition of the surface even after taking out of the vacuum chamber. To investigate the surface electron state and Fermi level, we employed the photoelectron spectroscopy with several photon energy from synchrotron radiation facility in Tosu (Saga Light Centre). Spectrum analysis from these samples is undergoing. Through this work, we established an easy and reliable method of arsenic capping in the MBE chamber, that were also checked by photoelectron spectroscopy because we could see clear evidence of clean surface after removing the arsenic capping layer by heat decapping.