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Titolo:
Photovoltage imaging of a single As-vacancy at a GaAs(110) surface: Evidence for electron trapping by a charged defect?
Autore:
Aloni, S; Nevo, I; Haase, G;
Indirizzi:
Weizmann Inst Sci, Dept Chem Phys, IL-76100 Rehovot, Israel Weizmann Inst Sci Rehovot Israel IL-76100 Phys, IL-76100 Rehovot, Israel
Titolo Testata:
JOURNAL OF CHEMICAL PHYSICS
fascicolo: 4, volume: 115, anno: 2001,
pagine: 1875 - 1881
SICI:
0021-9606(20010722)115:4<1875:PIOASA>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
SCANNING-TUNNELING-MICROSCOPY; TRANSITION; GAAS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
24
Recensione:
Indirizzi per estratti:
Indirizzo: Haase, G Weizmann Inst Sci, Dept Chem Phys, IL-76100 Rehovot, Israel Weizmann Inst Sci Rehovot Israel IL-76100 76100 Rehovot, Israel
Citazione:
S. Aloni et al., "Photovoltage imaging of a single As-vacancy at a GaAs(110) surface: Evidence for electron trapping by a charged defect?", J CHEM PHYS, 115(4), 2001, pp. 1875-1881

Abstract

We employed atomically-resolved surface photovoltage (SPV) imaging with a scanning tunneling microscope, using super- and sub-band gap energy photons, to map the potential distribution around a single As vacancy at a p-GaAs(110) surface. While the super-band gap (532 nm) SPV reflects the band bending (including the tip-induced effect) in the dark, the sub-band gap (1064 nm) SPV shows the change in band bending due to charge injection into the defect. We conclude that in the dark, the As vacancy introduces a surface state, similar to0.63 eV above the valence band maximum, that has to be filledwith two electrons to maintain surface neutrality. However, under 1064 nm (sub-band gap) illumination at room temperature, we observed a large negative SPV feature (radius of 70-100 Angstrom), and a zero or low positive SPV zone in its center, with a six-pointed star shape of similar to 15 Angstromradius. We interpret our findings as either negative photo-charging of thedefect, or positive charging that leads to a trapped electron state aroundthe defect. (C) 2001 American Institute of Physics.

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Documento generato il 07/07/20 alle ore 05:27:17