Investigation of the effect of crystal orientation on phonon thermal transport at the Cu/diamond interface by molecular dynamics

Abstract

Optimizing thermal transport across metal/semiconductor interfaces is crucial for developing next-generation thermal management solutions. This investigation employs non-equilibrium molecular dynamics (NEMD) simulations to quantify the crystallographic orientation effects on interfacial thermal conductance (ITC) at Cu/diamond interfaces with distinct surface morphologies. The results show that the effect of crystal orientation on the ITC of Cu/diamond is non-negligible. There is a difference in the effect of crystal orientation on ITC for flat and rough interface structures. The ITC of the Cu/diamond interface with the crystal orientation of [2 0 1] for the flat interface structure is 50.87 MW/m²-K, which is a 2.48-fold growth rate compared to the [0 0 1] crystal orientation. The analysis of the phonon density of states (PDOS) and phonon participation ratio (PR) reveals that the observed increase in ITC is attributed to the enhancement of phonon vibrational coupling at the interface and the improvement of the phonon localization phenomenon in the low-frequency region. The enhancement of [2 0 1] crystal orientation in ITC of Cu/diamond is less effective when the interface structure is rough. This is due to the fact that it is less effective in enhancing the phonon vibrational coupling and doesn't improve the phonon localization in the low-frequency region. These results establish crystallographic orientation engineering as a viable strategy for composite thermal conductivity enhancement, offering performance comparable to advanced material modification techniques while preserving interfacial integrity.