Effect of phonon-substrate scattering on lattice thermal conductivity of monolayer MoS₂

The effect of phonon-substrate scattering on lattice thermal conductivity (LTC) of supported MoS₂ MLs is investigated over a wide temperature range (1<T<500K). The phonons in the ML are considered to be scattered by the sample boundaries, isotopic impurities, vacancies and other phonons via Normal and Umklapp processes. The phonon-substrate scattering is taken into account following the treatment of Seol et al [Science 328, 213 (2010)]. Using phonon Boltzmann transport equation, LTC is evaluated within a modified Callaway formalism. It is found that, compared to a free-standing ML, the magnitude of LTC for supported ML MoS₂ is suppressed by nearly 50%, the suppression being more at intermediate temperatures (50<T<200K). The reduction in LTC is found to depend largely on the density of scattering centers.