Analysis of carbon content in direct-write plasmonic Au structures by nanomechanical scanning absorption microscopy

Abstract

The determination of the chemical content is crucial for the quality control in high-precision device fabrication and advanced process development. For reliable chemical composition characterization, certain interaction volume of the target material is necessary for conventional techniques such as energy-dispersive X-ray spectroscopy (EDX) and electron energy loss spectroscopy (EELS). This remains however a challenge for nanostructures. We hereby propose an alternative technique for measuring chemical composition of nanostructures with limited volume. By measuring the differences in the optical absorption of the nanostructure due to the differences in the chemical composition with the resonance frequency detuning of a nanomechanical resonator as well as the assistance of the analytical optical modelling, we demonstrate the possibility of characterizing the carbon content in the direct-write focused electron beam induced deposition (FEBID) gold nanostructures.

Photothermal Microscopy and Spectroscopy with Nanomechanical Resonators

“…27,34 Again, trampoline nanoresonators enabled also analysis of the carbon content of direct-write plasmonic Au nanostructures, verifying the corresponding enhancement of localized surface plasmon fields between two bowtie structures. 35 Due to their high sensitivity, the nanomechanical resonator photothermal method excels in fingerprinting low-abundance species, due to its high sensitivity and resolution. Being a single-laser method, nanomechanical resonators allow for versatile adaptation across a broad spectral range.…”

Recent Advancements of LSPR Fiber-Optic Biosensing: Combination Methods, Structure, and Prospects

“…Using a tightly focused electron beam, nanoscale-shaped three-dimensional structures can be created [ 57 ]. In general, the preparation of nanoparticle patterns on optical fibers is usually realized by the combination of the EBID method and FIB milling method, which is called focused electron beam-induced deposition [ 58 ] (FEBID). In the FEBID method, the electron beam provides a smaller spot for better focusing and resolution, which is beneficial to the FIB milling method while avoiding FIB-induced gallium contamination in and near the deposited material [ 59 ].…”

Plasmonics: Enabling functionalities with novel materials

“…To contribute to the understanding of the optical responses of patterned substrates, an explanation of the ellipsometric response using heuristic physical arguments is advanced by Hingerl. 16 In addition to more standard analysis methods, a new technique based on nanomechanical scanning absorption microscopy (NSAM) is introduced by Chien et al 17 Several articles focus on modeling and implementing characterization tools for plasmonic materials and their hybrid structures. Starting from fundamental properties, the permittivity dispersion behavior of all plasmonic materials is determined.…”