Thermal conductive performance of deposited amorphous carbon materials by molecular dynamics simulation

ABSTRACT

A series of diamond-like carbon (DLC) films with different microstructure were prepared by depositing carbon atoms on diamond surface with incident energy ranging from 1 to 100 eV. The thermal conductivity of the deposited films and the Kapitza resistance between the film and the diamond substrate were investigated. Results show that the average density, the average fraction of sp³ bonding and the thermal conductivity of the DLC films increase first, reaching a maximum around 20–40 eV before decreasing, while the Kapitza resistance decreases gradually with increased deposition energy. The analysis suggests that the thermal resistance of the interface layer is in the order of 10⁻¹⁰ m²K/W, which is not ignorable when measuring the thermal conductivity of the deposited film especially when the thickness of the DLC film is not large enough. The fraction of sp³ bonding in the DLC film decreases gradually normal to the diamond surface. However, the thermal conductivity of the film in normal direction is not affected obviously by this kind of structural variation but depends linearly on the average fraction of sp³ bonding in the entire film. The dependence of the thermal conductivity on the fraction of sp³ bonding was analysed by the phonon theory.

KEYWORDS:

• Diamond-like carbon films
• Kapitza resistance
• molecular dynamics simulation
• thermal conductivity

Acknowledgement

The computations are carried out at the National Supercomputing Center in ShenZhen.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work is financially supported by Natural Science Foundation of China [grant number 51376191], [grant number 51321002] and Open Fund of Medical Optical Key Laboratory of Jiangsu Province [grant number JKLMO201401].