Structural and electrical properties tailoring of carbon nanotubes via a reversible defect handling technique

Abstract

Irradiation with energetic particles has been recently demonstrated as an effective means to tailor the structures of a variety of materials with high precision, which, however, usually leading to irreversible degradation of the related properties due to defect introduction. Herein, we present a highly controllable defect handling approach, i.e. defect creation followed by their elimination in carbon nanotubes (CNTs). Technically, this can be accomplished by the alternate use of room-temperature electron irradiation and a separated heat treatment, as demonstrated here via in-situ transmission electron microscopy. The regarded CNTs thus undergo the order/disorder structural transition, which can be repeated up to at least 10 cycles with the CNT structural integrity largely retained. A temperature-dependent annealing experiment shows that the CNT recrystallization can be initiated at a surprisingly low temperature of ∼300 °C, and the irradiated CNTs can primarily regain their structural perfectness over 1000 °C. This technique allows for the reversible and repeatable tuning of a number of important CNT electrical properties, such as electron transport, as well as electron field emission that has never been achieved before. Furthermore, this defect handling technique has the potential as a general route for reversible tuning of other defect-dependent properties of sp2 carbon nanosystems.