ISSN:
1551-2916
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Scanning tunneling microscopy (STM) and spectroscopy (STS) have been applied to study the surface electronic properties of n -type BaTiO3 ceramics under ultrahigh vacuum and at various oxygen partial pressures. I–V tunneling characteristics of vacuum-annealed BaTiO3 do not exhibit rectifying behavior, implying that the Fermi level is pinned at the surface. The surface band gap of BaTiO3 annealed under vacuum at 540°C is equal to 1 eV. The top edge of the surface valence band is located 0.7 eV below the Fermi level. Hysteresis in the I–V characteristics has been observed at high oxygen partial pressures. Dosing of the BaTiO3 with oxygen increases the surface band gap and unpins the Fermi level. As a result, the I–V characteristics acquire rectifying features similar to those observed for BaTiO3 Schottky-type diodes. Hysteresis in the I–V spectra observed at high oxygen partial pressures is attributed to the changes of the surface potential barrier due to adsorption/desorption of oxygen modulated by the tip-sample potential difference.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1151-2916.2000.tb01160.x
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