Size- and shape-dependent plasmonic properties of aluminum nanoparticles for nanosensing applications

The localized surface plasmon resonance (LSPR) of aluminum nanospheres, nanorods, and nanodisks was studied using the finite-difference time-domain (FDTD) method. From the simulation results, optimal dimensions of nanospheres, nanodisks, and nanorods for refractive index sensitivity (RIS), line shape broadening (FWHM), and figure-of-merit (FOM) are calculated for aluminum-based plasmonic nanosensors. Our calculated results show that aluminum is an efficient plasmonic material for refractive index sensing from deep-UV to near infrared wavelengths. The RIS of aluminum nanospheres of optimal size is greater than gold and silver nanospheres. Further, RIS or FOM can be optimized in different spectral region by varying shape and dimensions. The optimization reveals higher FOM for nanospheres in the deep-UV region and for nanorods and nanodisks in the broad visible-NIR region.