Substrate influence on the vibrational response of gold nanoresonators: Towards tunable acoustic nanosources

The development of applications based on metallic nano-objects requires an extensive knowledge of their vibrational properties. Its size, shape, materials, or even crystallinity have a strong influence on the vibrational frequencies of a nano-object. It is also known that the coupling with environment has a strong effect on the lifetime of its resonating modes. However, the impact of the contact between a nano-object and its substrate still requires further investigation. Here we report on the vibrational response of gold disks for different contact area with a silicon substrate. The investigation of the quality factor of the first thickness mode of the disks highlights an important energy transfer from the disks to the substrate. The impact of the size of the contact area on the frequencies of the radial eigenmodes is also reported both experimentally and numerically. Finally, it is shown that such objects can be excited by acoustic waves propagating from the substrate. These findings display the possibility to use nanodisks to develop acoustic microscopy at the nanoscale.

Automated summary

The vibrational properties of metallic nano-objects are influenced by factors such as size, shape, material, crystallinity, and coupling with the environment. This study reveals that the contact area between a nano-object and its substrate affects the vibrational response of gold disks. Additionally, it demonstrates that nano-disks can be excited by acoustic waves propagating from the substrate, suggesting the potential use of nanodisks in developing nanoscale acoustic microscopy.