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Plasmonic propagations distances for interferometric surface plasmon resonance biosensing.

Lepage D, Carrier D, Jiménez A, Beauvais J, Dubowski JJ - Nanoscale Res Lett (2011)

Bottom Line: The result is an increased traceability of the SPR shifts for biosensing applications.The surface roughness and dielectric values for various deposition rates of very thin Au films are measured.We also investigate an interferometric SPR setup where, due to the power flux transfer between plasmon modes, the specific choice of grating coupler can either decrease or increase the plasmon propagation length.

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Affiliation: Department of Electrical and Computer Engineering, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada. Jan.J.Dubowski@USherbrooke.ca.

ABSTRACT
A surface plasmon resonance (SPR) scheme is proposed in which the local phase modulations of the coupled plasmons can interfere and yield phase-sensitive intensity modulations in the measured signal. The result is an increased traceability of the SPR shifts for biosensing applications. The main system limitation is the propagation distance of the coupled plasmon modes. This aspect is therefore studied for thin film microstructures operating in the visible and near-infrared spectral regions. The surface roughness of the substrate layer is examined for different dielectrics and deposition methods. The Au layer, on which the plasmonic modes are propagating and the biosensing occurs, is also examined. The surface roughness and dielectric values for various deposition rates of very thin Au films are measured. We also investigate an interferometric SPR setup where, due to the power flux transfer between plasmon modes, the specific choice of grating coupler can either decrease or increase the plasmon propagation length.

No MeSH data available.


Surface roughness for various dielectric materials and fabrication methods, as measured by ellipsometry. Uncertainties represent the standard variation between three independent material depositions [13].
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Figure 3: Surface roughness for various dielectric materials and fabrication methods, as measured by ellipsometry. Uncertainties represent the standard variation between three independent material depositions [13].

Mentions: To reduce the roughness, we analysed different materials and deposition techniques. The substrate layer on which the metallic layer is going to be deposited is the first concern, as its roughness will directly impact the quality of the subsequent thin films. All the films studied were deposited on Si substrate, whose surface roughness is below 8 Å under AFM. Figure 3 presents the surface roughness, measured by ellipsometry, for three dielectrics commonly employed in nanofabrication [13]. SiO2 is initially studied, for which three different fabrication methods were explored: e-beam evaporation, plasma sputtering and plasma-enhanced chemical vapour deposition (PECVD). Si3N4 is a good candidate, due to its relatively large dielectric constant, and was deposited through PECVD. The spin coating of a common electro resist, polymethyl methacrylate (PMMA), is also presented. On average, 300 nm of SiO2 or Si3N4 and 150 nm of PMMA were deposited atop Si substrates. Figure 3 shows that SiO2 deposited through PECVD is the best candidate for thin films in the present case, with a consistent surface roughness of 12.3 ± 0.8 Å. The energy-dependent dielectric values for the resulting layers have been measured by ellipsometry and are presented elsewhere [13]. SEM and AFM measurements were also carried, concurred with the presented results, but are not exposed here for clarity.


Plasmonic propagations distances for interferometric surface plasmon resonance biosensing.

Lepage D, Carrier D, Jiménez A, Beauvais J, Dubowski JJ - Nanoscale Res Lett (2011)

Surface roughness for various dielectric materials and fabrication methods, as measured by ellipsometry. Uncertainties represent the standard variation between three independent material depositions [13].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211481&req=5

Figure 3: Surface roughness for various dielectric materials and fabrication methods, as measured by ellipsometry. Uncertainties represent the standard variation between three independent material depositions [13].
Mentions: To reduce the roughness, we analysed different materials and deposition techniques. The substrate layer on which the metallic layer is going to be deposited is the first concern, as its roughness will directly impact the quality of the subsequent thin films. All the films studied were deposited on Si substrate, whose surface roughness is below 8 Å under AFM. Figure 3 presents the surface roughness, measured by ellipsometry, for three dielectrics commonly employed in nanofabrication [13]. SiO2 is initially studied, for which three different fabrication methods were explored: e-beam evaporation, plasma sputtering and plasma-enhanced chemical vapour deposition (PECVD). Si3N4 is a good candidate, due to its relatively large dielectric constant, and was deposited through PECVD. The spin coating of a common electro resist, polymethyl methacrylate (PMMA), is also presented. On average, 300 nm of SiO2 or Si3N4 and 150 nm of PMMA were deposited atop Si substrates. Figure 3 shows that SiO2 deposited through PECVD is the best candidate for thin films in the present case, with a consistent surface roughness of 12.3 ± 0.8 Å. The energy-dependent dielectric values for the resulting layers have been measured by ellipsometry and are presented elsewhere [13]. SEM and AFM measurements were also carried, concurred with the presented results, but are not exposed here for clarity.

Bottom Line: The result is an increased traceability of the SPR shifts for biosensing applications.The surface roughness and dielectric values for various deposition rates of very thin Au films are measured.We also investigate an interferometric SPR setup where, due to the power flux transfer between plasmon modes, the specific choice of grating coupler can either decrease or increase the plasmon propagation length.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electrical and Computer Engineering, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada. Jan.J.Dubowski@USherbrooke.ca.

ABSTRACT
A surface plasmon resonance (SPR) scheme is proposed in which the local phase modulations of the coupled plasmons can interfere and yield phase-sensitive intensity modulations in the measured signal. The result is an increased traceability of the SPR shifts for biosensing applications. The main system limitation is the propagation distance of the coupled plasmon modes. This aspect is therefore studied for thin film microstructures operating in the visible and near-infrared spectral regions. The surface roughness of the substrate layer is examined for different dielectrics and deposition methods. The Au layer, on which the plasmonic modes are propagating and the biosensing occurs, is also examined. The surface roughness and dielectric values for various deposition rates of very thin Au films are measured. We also investigate an interferometric SPR setup where, due to the power flux transfer between plasmon modes, the specific choice of grating coupler can either decrease or increase the plasmon propagation length.

No MeSH data available.