Schottky Heterojunction Engineering in Core–Shell SiC@Cu Nanowires for Ultra-Broadband Electromagnetic Wave Absorption and Rapid Heat Dissipation

The increasing miniaturization of electronic devices intensifies the challenges of electromagnetic interference and heat accumulation, demanding integrated solutions. Herein, a Schottky heterojunction engineering strategy is proposed through the rational design of one-dimensional core–shell SiC@Cu nanowires. A continuous, highly thermally conductive Cu layer is uniformly coated onto n-type SiC nanowires via electroless deposition, creating intimate Schottky interfaces. The significant work function difference between Cu and SiC generates a strong built-in electric field (BIEF), which dramatically enhances interfacial polarization loss. Coupled with the large specific surface area provided by the high-aspect-ratio SiC core, this results in exceptional microwave dissipation. With a filling ratio of 20 wt.%, the SiC@Cu achieves a remarkable minimum reflection loss of −51 dB and an ultra-broadband effective absorption bandwidth of 11.76 GHz, far surpassing the performance of bare SiC nanowire. Simultaneously, the conformal Cu shell establishes efficient heat conduction pathways, elevating the inter-plane thermal conductivity to 0.317 W m⁻¹ K⁻¹ at a volume ratio of only 1%, approximately twice that of its SiC nanowire counterpart (0.147 W m⁻¹ K⁻¹). This work pioneers a novel heterojunction-engineering approach for developing advanced multifunctional materials that concurrently manage electromagnetic and thermal energy.