Stabilizer Modulated Area-Selective Growth of Vertically Aligned Carbon Nanotube Forests toward Thermal Interface Materials

Abstract

Area-selective growth of vertically aligned carbon nanotube (VA-CNT) forests is critical for constructing spatially controlled thermal transport pathways in thermal interface materials. This capability is particularly important for thermal management scenarios involving complex interfacial topographies or localized heat-source distributions, where CNT forests need to be integrated within predefined regions. Here, adjustable growth selectivity was achieved on a patterned graphite/Al2O3 hybrid substrate using an Al2O3/Fe composite catalyst, in which Fe served as the active component for CNT growth and Al2O3 served as the stabilizer. While keeping the catalyst loading and chemical vapor deposition (CVD) conditions fixed, the overlying Al2O3 stabilizer was modulated via the ALD process to control the distribution and morphology of the Fe catalyst, which ultimately enabled the area-selective growth of VA-CNT forests. Molecular dynamics (MD) simulations provide atomistic support for stabilizer-modulated evolution of Fe catalysts on graphite, showing that increasing stabilizer coverage progressively suppresses Fe nanoparticle migration and coalescence while inducing coverage-dependent structural rearrangement and increased surface exposure. These results establish a practical stabilizer–substrate coupling route for regulating catalyst evolution to achieve area-selective VA-CNT growth and provide guidance for integrable, spatially controllable CNT array fabrication.