Temperature-dependent diffusive to ballistic transport transition in aligned double walled carbon nanotubes in the high frequency regime

Abstract

Low-temperature induced diffusive to ballistic transport in aligned double walled carbon nanotubes (DWNT) is reported. This is evidenced by a crossover of the imaginary (reactive) component of the alternating current impedance being greater than the real (resistive) component, which happens in the range of 9 GHz-1.5 GHz at temperatures77 K and 4 K from which we estimate a long lifetime of 17 ps and 106 ps in DWNTs, respectively. By simulating the measured scattering parameters of a few aligned DWNTs over a wide temperature range, we show that this observation is strongly influenced by the electrode-DWNT coupling strength.