Type‐II Heterojunction Regulated BIEF Toward Nitride/Chalcogenide Semiconductors for Multi‐Polarization Relaxation

Abstract Designing and constructing built‐in electric field (BIEF) between substances is an effective way to enhance multi‐polarization relaxation. Ni 3 S 4 @Co 4 S 3 /Ni 3 N@Co 2 N 0.67 (NC‐S/NC‐N) composites are prepared through multiple hydrothermal and nitriding steps. The influence of the BIEF constructed by the Type‐II heterojunction between the corresponding substances on the wave absorption performance is investigated. A BIEF model is constructed for this material, and the transfer mechanism of electrons and holes in the BIEF is studied. The crystal structure, lattice parameters, unit cell volume, and phase composition of composites are quantitatively analyzed by XRD refinement using the Rietveld method. The electronic structure of the heterointerface is studied by using density functional theory (DFT) calculations to verify the characteristics of Type‐II heterojunctions and the formation of BIEF. The BIEF constructed by Type‐II heterojunction enhances the interfacial polarization intensity by regulating the interfacial charge distribution, accelerates carrier transport, and increases conductive loss. It also affects magnetic loss by modulating the spin polarization of Ni/Co magnetic components. When the matching thickness is 2.1 mm, the minimum reflection loss (RL min ) can reach −51.64 dB. Meanwhile, the maximum effective absorption bandwidth (EAB max ) can cover 5.12 GHz at 2.3 mm. The results show that the microscopic interface mechanisms provides a brand‐new path.