Reactive Magnetron Sputtering of Large‐Scale 3D Aluminum‐Based Plasmonic Nanostructure for Both Light‐Induced Thermal Imaging and Photo‐Thermoelectric Conversion

Abstract Plasmonic nanostructures have attracted tremendous interest due to their special capability to trap light, which is of great significance for many applications such as solar steam generation and desalination, electric power generation, photodetection, sensing, catalysis, cancer therapy, and photoacoustic imaging. However, the noble metal‐based (Au, Ag, Pd) plasmonic nanostructures with expensive costs and limitations to large‐scale fabrication restrict their practical applications. Here, a novel and noble‐metal‐free Al/AlN plasmonic nanostructure fabricated by a reactive magnetron sputtering at the elevated temperature of 200 °C is presented. The unique 3D Al/AlN plasmonic nanostructures show a highly efficient (96.8%) and broadband (full solar spectrum) absorption and a strong photothermal conversion effect on its surface, demonstrating the potential in applications in light‐induced thermal imaging and photo‐thermoelectric power generation. This simple fabrication method and the developed Al/AlN plasmonic nanostructure combine excellent light trapping performance, abundant and low‐cost Al and N elements, good heat localization effect, and scalable fabrication method, suggesting a promising alternative to noble‐metal plasmonic nanostructures for photonic applications.