Thermal transport properties of bulk and monolayer MoS2: an ab-initio approach (original) (raw)

Reduced thermal conductivity of supported and encased monolayer and bilayer MoS2

2D Materials, 2020

Electrical and thermal properties of atomically thin two-dimensional (2D) materials are affected by their environment, e.g. through remote phonon scattering or dielectric screening. However, while it is known that mobility and thermal conductivity (TC) of graphene are reduced on a substrate, these effects are much less explored in 2D semiconductors such as MoS2. Here, we use molecular dynamics to understand TC changes in monolayer (1L) and bilayer (2L) MoS2 by comparing suspended, supported, and encased structures. The TC of monolayer MoS2 is reduced from ∼117 W m−1 K−1 when suspended, to ∼31 W m−1 K−1 when supported by SiO2, at 300 K. Encasing 1L MoS2 in SiO2 further reduces its TC down to ∼22 W m−1 K−1. In contrast, the TC of 2L MoS2 is not as drastically reduced, being >50% higher than 1L both when supported and encased. These effects are due to phonon scattering with remote vibrational modes of the substrate, which are partly screened in 2L MoS2. We also examine the TC of 1L ...

Thermal conductivity of MoS2 monolayers from molecular dynamics simulations

AIP Advances, 2019

Quantification of lattice thermal conductivity of two-dimensional semiconductors like MoS2 is necessary for the design of electronic and thermoelectric devices, but direct experimental measurements on free-standing samples is challenging. Molecular dynamics simulations, with appropriate corrections, can provide a reference value for thermal conductivity for these material systems. Here, we construct a new empirical forcefield of the Stillinger-Weber form, parameterized to phonon dispersion relations, lattice constants and elastic moduli and we use it to compute a material-intrinsic thermal conductivity of 38.1 W/m-K at room temperature and estimate a maximum thermal conductivity of 85.4 W/m-K at T = 200 K. We also identify that phonon scattering by the large isotopic mass distribution of Mo and S contributes a significant correction (>45%) to the thermal conductivity at low temperatures.

Previous Article Next Article Articles ASAP The Role of Transport Agents in MoS2 Single Crystals

The Journal of Physical Chemistry C

We report resistivity, thermoelectric power, and thermal conductivity of MoS 2 single crystals prepared by the chemical vapor transport (CVT) method using I 2 , Br 2 , and TeCl 4 as transport agents. The material presents low-lying donor and acceptor levels, which dominate the in-plane charge transport. Intercalates into the van der Waals gap strongly influence the interplane resistivity. Thermoelectric power displays the characteristics of strong electron−phonon interaction. A detailed theoretical model of thermal conductivity reveals the presence of a high number of defects in the MoS 2 structure. We show that these defects are inherent to CVT growth method, coming mostly from the transport agent molecules inclusion as identified by total reflection X-ray fluorescence analysis (TXRF) and in-beam activation analysis (IBAA).