The temperature dependence of the Debye temperature θD(T) was applied to analyze the lattice thermal conductivity of Si between 2 and 300 K. The analysis of experimental data in
terms of the Dubey model of the two modes of conduction has been carried out by combining the relaxation time for phonon-phonon
scattering, point defect scattering and boundary scattering. The relative importance of the contribution of each mode was
examined by estimating their percentage contribution to the phonon conductivity. Agreement between theory and experiment is
achieved over the whole temperature range of study.