Work

Au–Si Diffusion Effects on Surface Plasmon Resonance Sensor Using Internal Photoemission at Metal/Si Schottky Barrier

Year: 2025

Type: article

Abstract: Surface plasmon resonance sensors based on Schottky barriers have been extensively studied for their potential to enable compact, high-performance chemical sensing. These sensors utilize gold periodic structures on n-type silicon to couple surface plasmon resonance and convert it into electrical signals via internal photoemission at the gold/silicon (Au/Si) Schottky interface. However, stability over time remains challenging, as such sensors exhibit performance degradation. In this study, we investigate the mechanisms underlying performance degradation in surface plasmon resonance sensors utilizing a Au/Si Schottky barrier, with a particular focus on atomic diffusion at the interface. Rigorous 10-day continuous measurements of a conventional Au/Si sensor demonstrated silicon atom migration to the Au surface, hindering the device operation with a drop in responsivity of over 46%. An alternative design incorporating a molybdenum diffusion barrier layer to mitigate atomic diffusion effectively suppresses both the shift in the surface plasmon resonance angle and the degradation of responsivity over time, as confirmed by SPR response measurements and spectroscopy analysis. These findings address the crucial role of Si diffusion in resonance angle shifts and performance degradation.

Source: ACS Omega

DOI: 10.1021/acsomega.5c10956

Authors: Masaya Ukaji, Eslam Abubakr, Yuki Imai, Tetsuo Kan

Institutions: University of Electro-Communications, Aswan University

Language: English

Topic: Plasmonic and Surface Plasmon Research

Subfield: Biomedical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,935

Funders: Dementia Australia Research Foundation, Ministry of Education, Culture, Sports, Science and Technology, JKA Foundation