Study of Thermal Conductivity of Si and GaAs Quantum Nanowires

In this article, the thermal conductivity in one-dimensional devices, including semiconducting nanowires of silicon and gallium arsenide is calculated and plotted. The method used is solving the Boltzmann equation for phonon scattering. In case of purely specular interface scattering, the thermal conductivity is found to be high in silicon and gallium arsenide nanowires. The thermal conductivity increases with increasing nanowire diameter. In this work two different models for thermal conducting have been investigated. The first model solves the Boltzmann equation and finds solutions with the relaxation time approximation, and the other is a self-consistent solution of the Boltzmann equation. The answers in these two solutions are combined. The results show that the thermal conductivity in Si and GaAs semiconductor nanowires is reduced nearly 0.21 and 0.19 than that of bulk devices respectively in agreement to the reported data. It is found that the thermal conductivity of gallium arsenide nanowire is lower than that of silicon nanowire and comparing to recent published data for the corresponding Si nanowires with smaller diameter is overestimated and for larger nanowires diameter is underestimated which could be due to not taking into account the optical phonons decay to acoustic phonons and the effect of surface roughness on the thermal conductivity.