Molecular dynamics study of thermal transport in GaAs-self-assembly monolayer-GaAs junctions with ab initio characterization of thiol-GaAs bonds

摘要

Thermal dissipation in molecular electronic devices is a critical issue for the proper functioning of such devices. In this work, molecular dynamics (MD) simulations were carried out to study the thermal energy transport in GaAs-SAM (self-assembly monolayer)-GaAs junctions, with alkanedithiols being the SAM molecules. In order to characterize the molecule-GaAs interface, ab initio density functional theory (DFT) was used to study the structural and binding properties of alkanethiolates on GaAs(001) surfaces. Parameters of classical potentials, which were used to model the molecule-GaAs interactions, were obtained by fitting to the results from the DFT calculations. Then, nonequilibrium MD (NEMD) simulations were performed to reveal the GaAs-SAM interfacial thermal conductance at different temperatures. The results from this work showed that the GaAs-SAM interfaces are the major sources of thermal resistance in the GaAs-SAM-GaAs junctions. The delocalized phonon modes carry thermal energy efficiently inside the molecule chains, and the anharmonicity at the interface plays an important role in the thermal transport between the substrate and the molecules.