Interfacial thermal transport suppression by hydrogen insertion in an epitaxial Al/Si heterostructure

Engineering of interfacial thermal transport is crucial for efficient heat-to-electricity conversion and cooling of electronic devices. Here, we achieve remarkably high interfacial thermal conductance in a series of aluminum/silicon heterostructures grown by molecular beam epitaxy, up to 0.49 GW m−2 K−1 at room temperature, which is ∼29% greater than state-of-the-art values. The pristine interface is near perfect without any notable defects, as confirmed by atomic-resolution transmission electron microscopy. Density functional theory calculations reveal the possible covalent bonding between Al and Si at the interface. Intriguingly, by inserting a monolayer of hydrogen atoms at the interface, the conductance can be reduced by ∼47%. Molecular dynamics simulations show that phonon transmission is primarily suppressed within the frequency range from 2 to 7 THz. Our work highlights the potential of manipulating interfacial thermal transport at the atomic scale and may facilitate diverse applications in thermal management and energy harvesting.