Influence of the Size Reduction on the Thermal Conductivity of Bismuth Nanowires

Theoretical calculations on the lattice thermal conductivity (LTC) of the bulk bismuth (Bi) and nanowires (NWs) have been studied with diameters 98 nm, 115 nm and 327 nm in the 〈110〉 direction from temperature range of 0 to 300 K. Several size dependent parameters are estimated to correlate the value of LTC using the modified Morelli-Callaway model, including mass density, Umklapp, normal, boundary impurity, dislocation, and phonon-electron scattering rate. In a particular range of temperature, their effects are varied on the bell-shaped LTC. In accordance, Grüneisen parameter has been calculated for each case and the obtained values fitted with the experimental data of LTC. The result indicates that the impact of increasing the surface area to volume ratio is satisfied on the LTC for some Bi NWs. At a specific temperature, the LTC drops with the reduction of size of NWs. The effects of the variation in size on LTC are calculated and the obtained results are in good agreement with the experimental data.