Electric properties change of single-walled carbon nanotube with amphoteric doping by encapsulation of organic molecules inside carbon nanotube

Reaction of SWNTs with molecules having large electron affinity and small ionization energy achieved p-type(C/sub 60/, tetracyano-p-quiodimetaane) and n-type(terathiafulvalene, n-thiol series depend on chain length) doping, respectively. Doping changed electric property drastically by charge transfer depend on encapsulated molecules. Optical characterization (near-IR) and electric property (conductivity, field emission) revealed that charge transfer between SWNTs and molecules starts at certain critical energies.