Abstract
Using laterally ordered arrays of noble metal nanocavities as SERS substrates has been examined theoretically and experimentally. Simulation of the distribution of the electric field at the surface of nanostructures (nanocavities) has been carried out. The simulation results showed that cavities can be formed not only in a metal layer but in semiconductor or dielectric layers and then covered with a layer of a plasmon-supporting metal (silver or gold) 20…100-nm thick. In our work, chalcogenide glass has been used as a relief-forming layer. This paper presents the results of development and optimization of processes providing formation of SERS substrates as two-dimensional arrays of noble metal nanocavities by using interference photolithography based on a two-layer chalcogenide photoresist. Prototypes of SERS substrates were made as substrates with different spatial frequencies (from 1200 to 800 mm -1 ) and depths of nanocavities (from 250 up to 500 nm). It was shown that the use of such nanocavities with the sizes larger than 500 nm enables to efficiently analyze the structure of macromolecules by using surface- enhanced Raman light scattering spectroscopy, since these macromolecules completely overlap with the regions of enhanced electric field inside the nanocavities. Technology of interference lithography based on two-layer chalcogenide photoresists makes it possible to form effective SERS substrates in the form of laterally ordered arrays of nanocavities with specified morphological characteristics (spatial frequency, nanocavity sizes, composition and thickness of a conformal metal coating) for detecting high-molecular compounds.
Published Version
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