Effects of GaN substrates of different polarity on the thermal and electronic properties of monolayer MoS₂

Monolayer MoS₂, a compound in two-dimensional TMDs, exhibits excellent physical and chemical properties due to its sandwich structure, making it widely used in the design of nanodevices. We investigated the impact of GaN substrates on the thermal and electronic properties of monolayer MoS₂. The results reveal that the polarity of the GaN substrate significantly affects the thermal conductivity of monolayer MoS₂. The surface layer of the GaN substrate can be a Ga layer or an N layer, and in this paper, we investigated the effect of the surface layer type of the GaN substrate on the thermal conductivity of GaN supported monolayer MoS₂, and denoted the GaN substrate with a Ga surface layer as Ga-GaN and the GaN substrate with an N surface layer as N-GaN. This reduction is primarily attributed to the enhanced Mo-S antibonding with the Ga-GaN substrate, leading to increased phonon anharmonicity. Notably, while the Ga-GaN substrate has a minimal effect on the electronic properties of MoS₂, its impact on reducing thermal conductivity is more pronounced, thereby substantially enhancing the thermoelectric performance of the overlying material. This study provides valuable insights for the application of monolayer MoS₂ in thermal management.