Molecular-scale quantum dots from carbon nanotube heterojunctions.

Chandra, Bhupesh; Bhattacharjee, Joydeep; Purewal, Meninder; Son, Young-Woo; Wu, Yang; Huang, Mingyuan; Yan, Hugen; Heinz, Tony F et al. · Nano Lett · 2009

basic_science · Level V

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Abstract

Carbon nanotube heterojunctions (HJs), which seamlessly connect nanotubes of different chiral structure using a small number of atomic-scale defects, represent the ultimate scaling of electronic interfaces. Here we report the first electrical transport measurements on a HJ formed between semiconducting and metallic nanotubes of known chiralities. These measurements reveal asymmetric IV-characteristics and the presence of a quantum dot (QD) with approximately 60 meV charging energy and approximately 75 meV level spacing. A detailed atomistic and electronic model of the HJ enables the identification of specific defect arrangements that lead to the QD behavior consistent with the experiment.