Density Functional Theory Investigation of Electronic and Phonon Transport in Monolayer MoS2/WSe2 van der Waals Heterostructures

Monolayer transition metal dichalcogenides (TMDs) have emerged as pivotal building blocks for next-generation nanoelectronic and optoelectronic devices. In this work, we present a comprehensive first-principles study based on density functional theory (DFT) coupled with Boltzmann transport theory to systematically investigate the electronic band structures, optical properties, and phonon transport behavior in monolayer MoS2/WSe2 van der Waals (vdW) heterostructures. Our computational framework employs the HSE06 hybrid functional alongside Grimme DFT-D3 dispersion corrections to accurately capture interlayer interactions and band alignments. The results demonstrate that the MoS2/WSe2 heterostructure forms a staggered Type-II band alignment with a direct bandgap of 1.42 eV, promoting efficient spatial separation of photo-generated electron-hole pairs. Furthermore, full iterative solutions to the phonon Boltzmann transport equation reveal a significant suppression of lattice thermal conductivity in the heterostructure (22.4 W/mK at 300 K) compared to pristine MoS2 (84.2 W/mK) and WSe2 (38.6 W/mK) monolayers, driven by strong interfacial acoustic-phonon scattering and hybridization. Additionally, the electronic transport calculations indicate a high Seebeck coefficient and an enhanced thermoelectric power factor at room temperature. These findings highlight the fundamental physics governing coupled charge and heat transport in TMD heterostructures, providing valuable theoretical guidance for designing energy-efficient flexible electronics, photovoltaics, and thermoelectric energy harvesters.