Avalanche-Induced Current Enhancement in Semiconducting Carbon Nanotubes

Semiconducting single-wall carbon nanotubes under high electric field stress ($\sim 10\mathrm{V}/\mu \mathrm{m}$) display a remarkable current increase due to avalanche generation of free electrons and holes. Unlike other materials, the avalanche process in such 1D quantum wires involves access to the third subband and is insensitive to temperature but strongly dependent on diameter $\sim \exp (-1/d^2)$. Comparison with a theoretical model yields a novel approach to obtain the inelastic optical phonon emission length ${\lambda }_{\mathrm{OP},\mathrm{ems}}\approx 15d\mathrm{nm}$. The new results underscore the importance of multiband transport in 1D molecular wires.