Effect of the thickness of amorphous silicon intermediate layer on the thermal transport of silicon/diamond interface

•The TBC of the Si/diamond heterointerface increases by more than 38 % compared to that of the Si/diamond without the a-Si layer by introducing a 0.5-nm-thick a-Si layer.•The results of the phonon vibrational spectrum reveal that the enhancement of TBC is mainly attributed to the improved phonon mismatch between Si and diamond after introducing a thinner a-Si intermediate layer.•The increase of the TBC with increasing temperature is mainly attributed to the scattering between inelastic phonons at the interface.