Thermal management and phonon transport in BAs/WSe2 heterostructure: First-principles insights for optoelectronic applications

Abstract

Understanding the thermal management of van der Waals (vdW) heterostructures is vital for their implementation in optoelectronic applications. In this work, we systematically investigate lattice dynamics related to thermal properties and phonon transport behaviors of a two-dimensional BAs/WSe₂ heterostructure using first-principles calculations combined with phonon and thermal transport analysis. Phonon dispersion spectrum reveals strong anharmonicity and low-frequency optical–acoustic coupling, contributing to significant lattice softening and thermally activated phonon modes. Heat capacity analysis shows a distinct volume-dependent increase and temperature saturation trend, reflecting the full excitation of low-energy phonons at elevated temperatures. The thermal conductivity exhibits a strong temperature dependence, decreasing from 27 W/mK at 100 K to 2.5 W/mK at 1000 K, primarily due to phonon–phonon scattering. The cumulative thermal conductivity confirms that more than 90 % of heat is carried by phonons with mean free path (MFP) < 10 nm. Moreover, low-frequency optical phonons with extended lifetimes and large group velocities, enabled by acoustic–optical coupling, contribute significantly to thermal transport. These findings reveal that the BAs/WSe₂ heterostructure provides both efficient in-plane thermal conduction and localized heat dissipation, making it a promising candidate for thermally stable photodetectors and emitter devices.