Light absorption and scattering of 40–170 nm gold nanoparticles on glass substrates

Abstract

The localized surface plasmon resonance (LSPR) effect in metal nanoparticles is important for many applications ranging from detectors and sensors to photovoltaic devices. The LSPR wavelength is sensitive to the shape, size, surface condition, and surrounding environment. Therefore, it is important to compare the optical properties of metal nanoparticles of nominally similar dimensions and external conditions, but fabricated with different techniques. Here, a systematic study of the optical properties of large, periodic arrays (3 × 3 mm) of cylindrical, gold nanoparticles with diameters ranging from 39 ± 4 nm to 167 ± 5 nm and a height of 25 ± 1 nm is presented. The large arrays allow us to investigate the optical properties using an integrating sphere setup collecting the light scattered and absorbed by the nanoparticles. To the best of our knowledge, such a setup has not been used previously for electron beam lithography (EBL) fabricated samples mainly due the large sample area required. The authors compare our results with relevant literature and find a good agreement, which confirms the expected reproducibility of EBL. Further, the authors compare our absorption and scattering measurements with previous absorption and scattering measurements on large arrays of gold nanoparticles prepared on glass using hole-mask colloidal lithography. Finally, a comparison with simulations using a finite difference time domain software package (Lumerical, Inc.) is presented. The simulation results matches well with experimental results and are also supporting and detailing our comparison with published literature. The authors find a good agreement between the two fabrication methods. The small deviations found can be contributed to differences in the particle size and density distributions.