Defects and metallic contacts involving carbon nanotubes

Jisoon Ihm

School of Physics, Seoul National University, Korea

Effects of metallic contact on conductance of CNT

(5,5) CNT with a Stone-Wales defect

(without metallic electrode)

Atomic model (Au cluster + (5,5) CNT with SW + Au cluster)

Conductance plot with Vbias = 0.0 V

Fermi level = 0.0

For small voltage (≤ 0.1 V), ideal CNT : 1.0 G0

(effect of single gold contact: 3 KΩ),

CNT with SW : 0.93 G0

Conductance plot with Vbias = 1.0 V

ideal CNT : 0.5 G0

(effect of single gold contact: 10 KΩ) CNT with SW : 0.49 G0

Conductance plot with Vbias = 1.5 V

Energy (eV)

ideal CNT : 0.5 G0

(effect of single gold contact: 10 KΩ) CNT with SW : 0.49 G0

Atomic model (Au cluster + (5,5) CNT with SW + Au cluster)

broad gold electrode

narrow gold electrode

Broad gold contact

For small voltage (≤ 0.1 V), ideal CNT : 1.6 G0

(effect of single gold contact: 0.83 KΩ) CNT with SW : 1.55 G0

For large voltage (~ 1 V),

ideal CNT : 0.7 G0 (effect of single gold contact: 6 KΩ) CNT with SW : 0.7 G0

Semiconducting CNT–Gold resistance : 15 KΩ (Ohmic contact) ( McEuen Group, PRL 92, 046401 (2004) )

Summary of gold contact

• Gold contact gives additional resistance of ~ KΩ.

• Precise contact resistance is sensitive to the contact configuration.