High carrier mobility and strong electron–phonon coupling in graphene–WS2 heterobilayers under pressure

Abstract

Graphene-TMD heterojunctions with strong electron–phonon coupling are expected in nano-photodetectors, yet the chemical doping hinders the performance of graphene, and the limited photoelectric conversion and lack of effective regulation of interlayer interactions hinder further research on heterostructures. Here, we investigate the effect of hydrostatic pressure on vertically stacked monolayer-graphene and monolayer-WS₂ heterostructures, and the phonon pattern in the vertical direction is significantly enhanced during compression, indicating that the interlayer electron transition dominates. We further analyze the pressure evolution of doping concentration and Fano scattering, showing the three stages of charge transfer and the significant effect of pressure on the strength of electron–phonon coupling, which provide a platform for regulating the physical properties of quantum interference between electrons and phonons. Finally, density functional theory (DFT) calculations confirm the strong p-type doping in graphene and pressure-induced transitions in heterojunction band structures. These findings suggest that graphene-based heterobilayers are promising candidates for future optoelectronic applications.