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Metallic Electrode: Semiconducting Nanotube Junction ModelA model is proposed for two observed current-voltage (I-V) patterns in an experiment with a scanning tunneling microscope tip and a carbon nanotube [Collins et al., Science 278, 100 ('97)]. We claim that there are two contact modes for a tip (metal) -nanotube semi conductor) junction depending whether the alignment of the metal and semiconductor band structure is (1) variable (vacuum-gap) or (2) fixed (touching) with V. With the tip grounded, the tunneling case in (1) would produce large dI/dV with V > 0, small dI/dV with V < 0, and I = 0 near V = 0 for an either n- or p-nanotube. However, the Schottky mechanism in (2) would result in forward current with V < 0 for an n-nanotube, while with V > 0 for an p-nanotube. The two observed I-V patterns are thus entirely explained by a tip-nanotube contact of the two types, where the nanotube must be n-type. We apply this picture to the source-drain I-V characteristics in a long nanotube-channel field-effect-transistor (Zhou et al., Appl. Phys. Lett. 76, 1597 ('00)], and show that two independent metal-semiconductor junctions connected in series are responsible for the observed behavior.
Document ID
20010056904
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Yamada, Toshishige
(NASA Ames Research Center Moffett Field, CA United States)
Biegel, Bryon
Date Acquired
August 20, 2013
Publication Date
January 1, 2001
Subject Category
Solid-State Physics
Meeting Information
Meeting: American Physical Society March Meeting
Location: Seattle, WA
Country: United States
Start Date: March 12, 2001
End Date: March 16, 2001
Sponsors: American Physical Society
Funding Number(s)
OTHER: DTTS59-99-D-00437/A61812D
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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