H Okumura

Publications (2)1.34 Total impact

• Article: Photoemission studies of AlAs–GaAs alloys, heterostructures, and superlattices

  H. Okumura, I. Yoshida, S. Misawa, S. Yoshida
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  ABSTRACT: Inner core levels and valence‐band structures of molecular‐beam epitaxy‐grown Al x Ga 1-x As alloys, AlAs/GaAs heterostructures and [(AlAs) 2 (GaAs) 2 ] n superlattices were investigated by photoemission measurements. The variations in accordance with the structures were observed for the valence bands, while the binding energies of inner core levels of all the structures are constant within ±0.1 eV. The minimum layer thickness of GaAs or AlAs necessary to show its peculiar band structure was found to be 5∼6 monolayers. The valence‐band offset between AlAs and GaAs was estimated to be 0.12±0.33 eV. The spectra for the valence bands of superlattices showed the different features from those of GaAs, AlAs, and AlGaAs alloys.
  Journal of vacuum science & technology. B, Microelectronics and nanometer structures: processing, measurement, and phenomena: an official journal of the American Vacuum Society 12/1987; · 1.34 Impact Factor
• Article: PHOTOEMISSION STUDY OF ALLOYS AND HETEROSTRUCTURES OF III-V COMPOUND SEMICONDUCTORS

  H Okumura, I Yoshida, E. MUNEYAMA, S Misawa, K Endo, R Yoshida
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  ABSTRACT: The electronic structures of MBE-grown AlAs:GaAs, AlSb:GaSb and GaSb:GaAs compound semiconductor alloys and heterostructures were investigated by in-situ photoemission measurements. It was found that the binding energies of inner core levels for the alloys do not change with the compositions within ± 0.1eV, and correspond with those of the heterostructures. AlGaAs and AlGaSb alloys show some changes of valence bands in accordance with the compositions, while the variation of GaAsSb alloy is not monotonous. For AlAs-GaAs heterostructures, the minimum layer thickness necessary to show the bulk-like band structure was estimated to be 5-6 monolayers. The valence band offsets of AlAs-GaAs, AlSb-GaSb and GaSb-GaAs heterostructures were estimated to be 0.12, 0.19 and 0.35eV, respectively.
  http://dx.doi.org/10.1051/jphyscol:1987507.