Protocol to design plasmonic sensors for the characterization of materials at the atomic scale

Abstract

Materials characterization is essential since it is the basis for understanding materials’ physical and chemical properties before being used in any application. Nowadays, expensive equipment such as scanning electron microscopy and X-ray diffraction for thin film characterization at atomic layers are used. Atomic layer deposition (ALD) is a technique for growing thin films with a wide range of applications. The film thickness range is usually 1-500 nm. Plasmonic sensors are a low-cost technique for material characterization, including inorganic and organic thin films. The thickness resolution ranges from a fraction of a nanometer (monolayers) to several micrometers. These devices exploit the interaction of light with matter using surface plasmon resonance as a method based on the optoelectronic phenomenon. Kretschmann geometry continues to be a configuration widely used as an experimental setup to excite surface plasmon resonance in the characterization of different materials. It consists of a coupler prism with a thin metal film. The incident light in the total internal reflection at a specific angle, the evanescent wave transfers the energy to the electrons plasma of metal giving place surface plasmon resonance (SPR). The SPR effect in metals is highly sensitive to variations in the optical properties of the interface. We use the Kretschmann configuration and the matrix transfer method to analyze the performance numerically to achieve the optime parameters of design for the sensor’s performance. In this work, we developed a protocol to design and build a plasmonic sensor for the characterization of materials at the atomic layer level.