Abstract
In this work, we designed a sensitivity-enhanced surface plasmon resonance biosensor structure based on silicon nanosheet and two-dimensional transition metal dichalcogenides. This configuration contains six components: SF10 triangular prism, gold thin film, silicon nanosheet, two-dimensional MoS2/MoSe2/WS2/WSe2 (defined as MX2) layers, biomolecular analyte layer and sensing medium. The minimum reflectivity, sensitivity as well as the Full Width at Half Maximum of SPR curve are systematically examined by using Fresnel equations and the transfer matrix method in the visible and near infrared wavelength range (600 nm to 1024 nm). The variation of the minimum reflectivity and the change in resonance angle as the function of the number of MX2 layers are presented respectively. The results show that silicon nanosheet and MX2 layers can be served as effective light absorption medium. Under resonance conditions, the electrons in these additional dielectric layers can be transferred to the surface of gold thin film. All silicon-MX2 enhanced sensing models show much better performance than that of the conventional sensing scheme where pure Au thin film is used, the highest sensitivity can be achieved by employing 600 nm excitation light wavelength with 35 nm gold thin film and 7 nm thickness silicon nanosheet coated with monolayer WS2.
Highlights
IntroductionSince the refractive index changes of the sensing layer that are induced by the adsorption of biomolecules on the sensing surface would lead to a redistribution of SPR electromagnetic field, a significant SPR angle shift could be obtained and collected through an optical detector
Matches with the surface plasmon wave vector ksp, the surface plasmon resonance phenomenon occurs, as shown in equation (1), kx = k0nprismsin θinc = ksp (1)
We demonstrated a silicon nanosheet and 2D MX2 enhanced surface plasmon resonance biosensor
Summary
Since the refractive index changes of the sensing layer that are induced by the adsorption of biomolecules on the sensing surface would lead to a redistribution of SPR electromagnetic field, a significant SPR angle shift could be obtained and collected through an optical detector. This unique characteristic enables SPR biosensors to show excellent performances for real-time and label-free detections. The silicon nanosheet is able to enhance the sensitivity of the SPR biosensor because of its large real value of the refractive index It serves as a protective layer of metal film to improve the overall system stability[16,17]. This can be explained by the quantum confinement and resulted from the change in hybridization between orbital of Mo/W and X atoms[20,22]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
