Laser engineering of heterostructured graphitic petals on carbon nanotube forests for robust thermal interface capable of swift heat transfer

Abstract

Amongst graphene-carbon nanotube hybrid-based thermal interfaces, graphene petals (GP) grown on CNT forests (CNTF) seem apt, but petals grown out-of-plane gives compromised heat transfer when integrated to a heat sink. To address these technological challenges, KrF (248 nm) laser annealing and Nd-YAG laser shock peening of microwave plasma chemical vapour deposition (MPCVD) grown GP/CNTF have been employed for the first time and the discovery is reported here. While there is clear-cut evidence of exfoliation and flattening in laser annealing, laser shock peening effectively presses the sample very hard to squeeze source-sink distance. Photo-acoustic measurements revealed that laser processing significantly improves thermal interfaces. It is believed that present findings on all-carbon robust thermal interfaces capable of fast removal of heat from hot-spots and withstanding thermal spikes/shocks in practical thermal chips would guide future research and expand the range of thermal management applications.