Single and coupled quantum dots in single-wall carbon nanotubes

We have fabricated single and coupled quantum dots in single-wall carbon nanotubes, and measured their electrical transport:at low temperatures. The charging energy for single quantum dots seemed to depend on the gap between metallic contacts, and could be larger than room temperature for the smallest sample. Coupled quantum dots could be successfully fabricated by depositing a narrow SiO2 layer between source-drain contacts. The experimental observations of the stochastic Coulomb blockade and the negative differential conductance support the formation of the coupled quantum dots. The barrier formation in single and coupled quantum dots is also discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.