Direct observation of localized defect States in semiconductor nanotube junctions.
We report scanning tunneling microscopy of semiconductor-semiconductor carbon nanotube junctions with different band gaps. Characteristic features of the wave functions at different energy levels, such as a localized defect state, are clearly exhibited in the atomically resolved scanning tunneling spectroscopy. The peaks of the Van Hove singularity on each side penetrate and decay into the opposite side across the junction over a distance of approximately 2 nm. These experimental features are accounted for, with the help of tight-binding calculation, by the presence of pentagon-heptagon pair defects at the junction.
Kim
Hajin
H
School of Physics and Center for Science in Nanometer Scale, Seoul National University, Seoul 151-742, Korea.
Lee
J
J
Kahng
S-J
SJ
Son
Y-W
YW
Lee
S B
SB
Lee
C-K
CK
Ihm
J
J
Kuk
Young
Y