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 MoS₂ across a wide range of temperatures (300 K to 700 K) and defect densities (up to 5 10¹³ cm⁻²), finding that the substrate reduces the dependence of TC on these factors. Taken together, these are important findings for all applications which will use 2D semiconductors supported or encased by insulators, instead of freely suspended.

原子薄的二维（2D）材料的电和热特性受其环境的影响，例如，通过远程声子散射或介电屏蔽。然而，尽管已知石墨烯在基板上的迁移率和导热性（TC）降低，但是在诸如MoS _2的2D半导体中探索这些效应的机会要少得多。在这里，我们使用分子动力学通过比较悬浮，支撑和包裹的结构来了解单层（1L）和双层（2L）MoS _2中的TC变化。单层MoS ₂的TC从悬浮时的约117 W m ^-1 K ^-1降低到被SiO ₂支撑时的约31 W m ^-1 K ^-1，在300K装盒1L的MoS ₂中的SiO ₂进一步降低了其TC下降到约22脉冲W M ^-1 ķ ^-1。相反，2L MoS ₂的TC并没有显着降低，在支撑和封装时均比1L高出50％以上。这些影响是由于声子在基板的远程振动模式下的声子散射所致，而该振动模式已部分屏蔽在2L MoS _2中。我们还检查了1L MoS ₂在各种温度（300 K至700 K）和缺陷密度（高达5 10 ¹³ cm ^-2）下的TC），发现底物降低了TC对这些因素的依赖性。综上所述，这些对于所有使用绝缘体支撑或封装而不是自由悬挂的2D半导体的应用都是重要的发现。