Affiliation:
1. Materials Genome Institute Shanghai University Shanghai 200444 P. R. China
2. Laboratory of Advanced Materials Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Academy for Engineering & Technology Fudan University Shanghai 200438 P. R. China
3. Institute of Optoelectronics Fudan University Shanghai 200433 P. R. China
4. Pico Electron Microscopy Center Innovation Institute for Ocean Materials Characterization Center for Advanced Studies in Precision Instruments Hainan University Haikou Hainan Province 570228 P. R. China
5. College of Physics Donghua University Shanghai 201620 P. R. China
Abstract
AbstractWhen interacting with an external Electromagnetic (EM) field, symmetric nanostructures, characterized by their periodic crystalline arrangement, typically resonate at specific frequencies. This resonance enhances local electromagnetic fields, leading to strong EM absorption, yet within a narrow absorption range. Conversely, asymmetric nanostructures, distinguished by their complex electric field polarization and distributions, provide broader frequency responses, albeit with generally weaker electromagnetic loss across the broadband. Therefore, striking a balance between wideband and strong absorption using either symmetric or asymmetric nanostructures remains a challenge. Here, a nanostructured epitaxial step‐growth technique is demonstrated that fabricates a CuxS multilevel rod‐like heterostructure with overall axial symmetry. This structure introduces localized asymmetry through variations in a component hierarchy and multilevel rod dimensions during the epitaxial growth process, effectively addressing the aforementioned balance between wideband and strong absorption. Experimental evidence and theoretical simulations confirm that nanostructures possessing these characteristics achieve efficient broadband absorption across a 6.3 GHz bandwidth with just 2.0 mm thickness, owing to the generation of multiple continuous local electric fields and enhanced electric field polarization. It is convincing that this methodology and design concept hold enlightening significance for advancing material and technological innovations in the realm of broadband absorption.
Funder
National Natural Science Foundation of China
Ministry of Science and Technology of the People's Republic of China