Coating-boosted interfacial thermal transport for carbon nanotube array nano-thermal interface materials

The interfacial thermal transport (ITT) between vertically aligned carbon nanotube (VACNT) arrays and heat sink is the dominant barrier blocking the path towards practical application of VACNT arrays as nano-thermal interface materials (nTIMs). Although developing VACNT arrays with homogeneous heights and larger diameters could lower the thermal contact resistance between the arrays and heat sink (R _c ), little effect is achieved at present stage. Here, by using Plasma Enhanced Chemical Vapor Deposition approach, we attain DLC/TiN-coated VACNT arrays, which gives up to 50 times reduction in R _c from 15 mm ² K/W to 0.3 mm ² K/W. Microscopic morphological analyses confirm that the remarkably expanded contact area brought by coatings can promote the ITT and also retain the high phonon transmission rate within individual CNTs. These novel structures are significantly in favor of fulfilling a nTIM function. It is also intriguing to note that R _c is no longer linearly dependent on CNT height variations once CNT diameters become large enough. This indicates that the contact area with heat sink is dominant in influencing R _c instead of the surface roughness. The above findings fuel future effort towards industrial realization of high-performance VACNT array-based nTIM and high-efficiency thermal management in microelectronic and nanoenergy fields.