An Analysis of a Compact Label-Free Guiding-Wave Biosensor Based on a Semiconductor-Clad Dielectric Strip Waveguide

• Published in: Sensors (Basel, Switzerland) Vol. 20; no. 12; p. 3368
• Main Author: Angulo Barrios, Carlos
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 14.06.2020; MDPI
• Subjects: Amorphous materials; Aqueous solutions; Beams (radiation); Biofilms; Biosensing Techniques; Biosensors; Boundary conditions; CMOS; Computer simulation; integrated optics; Letter; optical biosensor; Optical measuring instruments; Optics and Photonics; photonic modeling; Propagation; Semiconductors; Sensors; Silicon oxynitride; Simulation; Strip; waveguide; Waveguides; optical biosensor; integrated optics; photonic modeling; waveguide
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s20123368

In this paper, a compact, integrated, semiconductor-clad strip waveguide label-free biosensor is proposed and analyzed. The device is based on CMOS-compatible materials such as amorphous-Si and silicon oxynitride. The optical sensor performance has been modeled by a three-dimensional beam propagation method. The simulations indicate that a 20-μm-long device can exhibit a surface limit of detection of 3 ng/cm for avidin molecules in aqueous solution. The sensor performance compares well to those displayed by other photonic biosensors with much larger footprints. The fabrication tolerances have been also studied in order to analyze the feasibility of the practical implementation of the biosensor.