Corso di Nanotecnologie 1 Prof. Di Zitti Anno accademico 2002-2003. Carbon Nanotube Quantum Resistor. Lotti Christian Carezzano Linda. SCIENCE,VOL.280,12 JUNE 1998 PHISICAL REVIEW LETTERS,VOL.84,NUM.9,28 FEBRUARY 2000. Carbon Nanotube. History and Definition:
Corso di Nanotecnologie 1
Prof. Di Zitti
Anno accademico 2002-2003
Carbon Nanotube Quantum Resistor
SCIENCE,VOL.280,12 JUNE 1998
PHISICAL REVIEW LETTERS,VOL.84,NUM.9,28 FEBRUARY 2000
consist of several nested cylinders with an interlayer spacing of 0.34 – 0.36 nm that is close to the typical spacing of turbostratic graphite.
in the ideal case, a carbon nanotube consist of either one cylindrical graphene sheet.
Considering MWNT as an extremely fine and constricted wave guide with a length smaller than the electronic mean free path.
Electronic transport is ballistic: every electron injected into the nanotube at one end come out the other end.
behaviour of nanotubes in 1998 Walt de Heer invented an ingenious way to measure the electrical conductance of MWNTs.
Schematics of an arc discharge
Carbon fiber TEM micrograpy
Transmission electron micrograph of the end of a nanotube fibe
recovered from a nanotube arc deposit
Because individual nanotubes stick out from the fiber, by dipping the nanotubes to different depths is possible to determine the resistance of individual nanotubes.
Vappotential (10-50 mV) was applied to the contact, the current through the circuit was measured together with the piezo displacement.
Nanotube is a quantized conductor
After a dipping distance of 200 nm there is a second step (the second tube comes into contact with the metal ~200nm after the first).
This effect can be related to the tip structure
of the nanotubes.
Power dissipated = 3 mW
Bulk thermal conductivity = 10 Wcm-1K-1
We would attain a temperature Tmax=20000°K
Impossible: nanotubes start to burn at~700°C
Hg(#2) – double-wall MWNT’s portion eq with Hg.
Hg(#3) – triple-wall MWNT’s portion eq with Hg.