Electron Paramagnetic Resonance and Scanning Tunneling Microscopy Investigations on the Formation of F + and F 0 Color Centers on the Surface of Thin MgO(001) Films
2006; American Chemical Society; Volume: 110; Issue: 17 Linguagem: Inglês
10.1021/jp060546t
ISSN1520-6106
AutoresMartin Sterrer, Esther Fischbach, Markus Heyde, Niklas Nilius, H.‐P. Rust, Thomas Risse, Hans‐Joachim Freund,
Tópico(s)ZnO doping and properties
ResumoThe formation of surface color centers (FS centers) by electron bombardment of thin MgO(001) films is investigated using electron paramagnetic resonance and low-temperature scanning tunneling microscopy. At low electron doses both techniques indicate the formation of singly occupied color centers (FS+), whereas at high electron doses the doubly occupied type (FS0) is dominant. It is suggested that with increasing electron dose FS+ centers are transformed into FS0. Tunneling spectra of individual FS0 centers reveal a large distribution of energetic positions of occupied and unoccupied states, which is caused by local variations of the coordination number of the defects and explains the broad signals usually detected with integrating spectroscopic techniques.
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