MXene-antenna electrode with collective multipole resonances

Abstract

Two-dimensional transition metal carbides and nitrides (MXene-s) are the focus of extensive research due to their exceptional potential for practical applications. We study nanostructured MXene layers to design photodetector electrodes and increase their response through hot-electron generation. We demonstrate that the lattice arrangement plays a crucial role in exciting strong optical resonances in the nanostructured MXene, specifically Ti₃C₂T_x, despite its high loss and weak optical resonances in an isolated antenna. We use numerical simulations and analytical calculations with coupled dipole–quadrupole lattice sums for designing photodetector electrodes. We also provide proof-of-concept experimental demonstration of the enhanced resonances even for the case of lossy materials. We report on the excitation of strong lattice resonances of the MXene antenna array with enhanced absorption, resulting in a more efficient generation of hot electrons. Our findings reveal that a multi-period array of MXene antennas can improve narrowband and broadband photodetector functionality. We propose highly efficient absorbers based on MXene metasurfaces and transforming electrodes into hybrid photodetectors using MXene antennas to enhance their performance.