Vertical graphene nanowalls (VGNs) with excellent heat-transfer properties are promising to be applied in the thermal management of electronic devices. However, high growth temperature makes VGNs unable to be directly prepared on semiconductors and polymers, which limits the practical application of VGNs. In this work, the near room-temperature growth of VGNs was realized by utilizing the hot filament chemical vapor deposition method. Catalytic tantalum (Ta) filaments promote the decomposition of acetylene at ∼1600 °C. Density functional theory calculations proved that C2H* was the main active carbon cluster during VGN growth. The restricted diffusion of C2H* clusters induced the vertical growth of graphene nanoflakes on various substrates below 150 °C. The direct growth of VGNs successfully realized the excellent interfacial contact, and the thermal contact resistance could reach 3.39 × 10–9 m2·K·W–1. The temperature of electronic chips had a 6.7 °C reduction by utilizing directly prepared VGNs instead of thermal conductive tape as thermal-interface materials, indicating the great potential of VGNs to be directly prepared on electronic devices for thermal management.

The CuCrSe2 shows attractive physical properties, such as thermoelectric and multiferroic properties, but pure-phase CuCrSe2 crystal is still quite challenging to obtain because CuCr2Se4 can be easily precipitated from a CuCrSe2 matrix. Here, taking the advantage of this precipitation reaction, we grew a series of CuCrSe2-CuCr2Se4 hetero-composites by adjusting growth parameters and explored their thermal conductivity property. Determined by electron-diffraction, the orientation relationship between these two compounds is [001] (100) CuCrSe2‖[111] (220) CuCr2Se4. The out-of-plane thermal conductivity κ of these hetero-composites was measured by a time-domain thermo-reflectance method. Fitting experimental κ by the Boltzmann-Callaway model, we verify that interface scattering plays significant role to κ in CuCrSe2-CuCr2Se4 hetero-composites, while in a CuCrSe2-dominated hetero-composite, both interface scattering and anharmonic three-phonon interaction lead to the lowest κ therein. Our results reveal the thermal conductivity evolution in CuCr2Se4-CuCrSe2 hetero-composites.