Tunable thermal conductivity of single layer MoS2 nanoribbons: an equilibrium molecular dynamics study

Abstract

Thermal transport in single-layer MoS2 nanoribbons (SLMOSNRs) has been comprehensively studied using equilibrium molecular dynamics (EMD) simulations based on the Green–Kubo formulation. The room-temperature thermal conductivity of a pristine ~ 10 nm × 4 nm zigzag MoS2 nanoribbon is computed to be ~ 117 W m−1 K−1 using the Stillinger–Weber (SW) interatomic potential. The thermal conductivity is also studied as a function of temperature and the dimensions of the sample. The thermal conductivity of SLMOSNRs is found to decrease with increasing temperature due to increased phonon–phonon Umklapp scattering, while it shows the opposite trend as the length is increased. With increasing length, the thermal conductivity initially increases rapidly but gradually less so. The thermal conductivity exhibits a similar trend with increasing sample width. Moreover, the impact of defect engineering, an effective tool for tailoring the thermal transport in single-layer MoS2 by considering various defects, namely point vacancies, bi-vacancies, and edge vacancies, is studied. The results of this study show that the thermal conductivity of SLMOSNRs with defects is significantly reduced compared with their pristine counterparts. The reduction of the thermal conductivity with increasing defect concentration is greater at low than high concentration. To study the underlying mechanism responsible for such characteristics, the phonon density of states (PDOS) of SLMOSNRs is calculated. This study provides a detailed demonstration of how the thermal transport characteristics of MoS2 nanostructures can be tuned, promoting the potential application of MoS2 in thermoelectric and nanoelectronic devices.