1 research outputs found
Electrical Monitoring of sp<sup>3</sup> Defect Formation in Individual Carbon Nanotubes
Many carbon nanotube (CNT) applications
require precisely controlled
chemical functionalization that is minimally disruptive to electrical
performance. A promising approach is the generation of sp<sup>3</sup> hybridized carbon atoms in the sp<sup>2</sup>-bonded lattice. We
have investigated the possibility of using a carboxylic acid-functionalized
diazonium reagent to introduce a defined number of sp<sup>3</sup> defects
into electrically contacted CNTs. Having performed real-time measurements
on individually contacted CNTs, we show that the formation of an individual
defect is accompanied by an upward jump in resistance of approximately
6 kΩ. Additionally, we observe downward jumps in resistance
of the same size, indicating that some defects are unstable. Our results
are explained by a two-step reaction mechanism. Isolated aryl groups,
formed in the first step, are unstable and dissociate on the minute
time scale. Stable defect generation requires a second step: the coupling
of a second aryl group adjacent to the first. Additional mechanistic
understanding is provided by a systematic investigation of the gate
voltage dependence of the reaction, showing that defect formation
can be turned on and off. In summary, we demonstrate an unprecedented
level of control over sp<sup>3</sup> defect formation in electrically
contacted CNTs, and prove that sp<sup>3</sup> defects are minimally
disruptive to the electrical performance of CNTs