A molecular dynamics investigation of heat transfer across a disordered thin film

The structure of a thin film confined between two materials widely exists in microelectronic devices. When heat flows across such a thin film, thermal resistance of the film is always coupled with the thermal resistances of the two interfaces. Comparing to numerous studies on the heat transfer across an interface between two dissimilar materials, heat transfer across a thin film and the adjacent interfaces is less investigated, especially when the film has structural or mass disorder. Using molecular dynamics simulations, we systematically investigate the net thermal resistance of two interfaces and the confined thin film, and compare the results with the predictions from the thermal circuit model. When the thickness of a disordered thin film is greater than 2 nm, the net resistance across the film is almost linearly dependent on the film thickness and always larger than the prediction of the thermal circuit model. For extremely small thickness (<2 nm), the amorphous thin film has similar resistance to the crystalline counterpart. The existence of alloy region between two dissimilar materials could reduce the interfacial resistance when the alloy thickness is a few atomic layers, but would enhance the resistance when the alloy thickness is large. (C) 2015 Elsevier Ltd. All rights reserved.