Electron Switch With Tunable Absorption Across Electromagnetic Frequency Bands Controlled by Schottky Barrier

Traditional electromagnetic wave absorbing materials have achieved significant progress in efficiently mitigating electromagnetic pollution and expanding absorption bandwidth through macroscopic composite and morphological design. However, the decisive role of microscopic heterojunctions in charge transport and polarization behavior remains unclear, hindering active manipulation of absorption bands via interface design. This study modulates the band structure of SiC/Cu via W/Ni doping to regulate the Schottky barrier at the interface. Ni doping lowers the work function, reducing the barrier and opening the electron gate to promote charge migration. In contrast, W doping raises the work function, increasing the barrier and confining interfacial charge. Combined experiments and DFT calculations show that a low barrier enhances conductive loss in the C‐band. Sample CNi‐2 achieves a 5.9 GHz absorption bandwidth at 5.9 mm, with full absorption from 3.6 to 5.9 GHz. A high barrier strengthens interfacial polarization, boosting Ku‐band absorption. CW‐3 reaches 6.5 GHz at 2.2 mm, covering 93% of the Ku band. Undoped SiC/Cu exhibits competing loss mechanisms, absorbing mainly in the X‐band. This work offers a band‐engineering strategy for designing tunable, high‐performance absorbers, with promising applications in electromagnetic protection and stealth technology.