Thermal conductivity analysis of single-walled carbon nanotube using finite element modeling

Abstract

The focus of the present paper is to develop a fundamental understanding of the heat conduction process in single-walled carbon nanotubes and to elucidate the contribution of the various factors which affect it at the nanometer level. As the sizes of electronic and mechanical devices are decreased to the micron and nanometer level, it becomes particularly important to predict the thermal transport properties of the components. The heat conduction in finite length SWNTs was simulated by the finite element method. Temperature at each end of an SWNT was controlled in the simulation, and the thermal conductivity was calculated from the measured temperature gradient and heat flow value. The thermal conductivity was measured for (10, 10) SWNTs with various lengths from 40 through 80 nm. The measured thermal conductivity for smaller diameter (10, 10) nanotube did not converge to a finite value with increase in tube length but obeyed a striking power law relation. The thermal conductivity of several single-wall carbon nanotubes has been calculated over a temperature range of 100-500 K using finite element method. In all cases, starting from similar values at 100 K, the thermal conductivities show a peaking behavior. The output result (Thermal Conductivity) varied from 1000 to 5266 w/m-k. The simulation results are quite similar with the results that are obtained by molecular dynamics simulation and photon spectrum analysis. We have also simulated the effect of defects in our SWNT structure. In the paper the difference of thermal conductivity between a defective and non-defective SWNT is also being discussed. M ore detailed analysis can be done to understand the defect influence on the thermal conductivity of carbon nanotube. The specific heat is a function of temperature [1]. We used 700 J/kg-k here as our average temperature is 300k. So, in future we hope there will be these corrections to determine the more accurate conductivity.