Surface roughness boosts the SERS performance of imprinted plasmonic architectures

2016 ◽  
Vol 4 (18) ◽  
pp. 3970-3975 ◽  
Author(s):  
Gerard Macias ◽  
María Alba ◽  
Lluís F. Marsal ◽  
Agustín Mihi
Keyword(s):  
Surface Roughness ◽  
Plasmonic Crystals ◽  
Sers Substrates ◽  
Enhancement Factors

Rough 2D plasmonic crystals pose as inexpensive and easily processed SERS substrates exhibiting enhancement factors up to 1.6 × 1010.

scholarly journals An advance Towards the Synthesis of Ag Nanorod Arrays with Controlled Surface Roughness for SERS Substrates

2016 ◽  
Vol 3 (2) ◽  
pp. 294-302 ◽  
Author(s):  
M. Gómez-Gómez ◽  
J. Calderón ◽  
R. Abargues ◽  
P.J. Rodríguez-Cantó ◽  
I. Suárez ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Nanorod Arrays ◽  
Sers Substrates

Solution processed nanomanufacturing of SERS substrates with random Ag nanoholes exhibiting uniformly high enhancement factors

RSC Advances ◽  
2015 ◽  
Vol 5 (103) ◽  
pp. 85019-85027 ◽  
Author(s):  
Ritu Gupta ◽  
Soumik Siddhanta ◽  
Gangaiah Mettela ◽  
Swati Chakraborty ◽  
Chandrabhas Narayana ◽  
...  
Keyword(s):  
Surface Plasmons ◽  
Electrical Activation ◽  
Raman Signal ◽  
Interference Effects ◽  
Optical Interference ◽  
Solution Processed ◽  
Sers Signal ◽  
Sers Substrates ◽  
Enhancement Factors ◽  
Ag Film

An Ag film exhibits an enhanced Raman signal over unusually large areas due to surface plasmons around its nanoholes. The SERS signal is increased by optical interference effects and the uniformity of the signal is improved by electrical activation.

High performance SERS substrates using high surface roughness gold nanosheets assembled by nanowires

2020 ◽  
Vol 107 ◽  
pp. 103041 ◽  
Author(s):  
Dapeng Xu ◽  
Zixiong Wang ◽  
Song Zhang ◽  
Wei Yang ◽  
Jian Chen
Keyword(s):  
Surface Roughness ◽  
High Performance ◽  
High Surface ◽  
Sers Substrates ◽  
High Surface Roughness

scholarly journals Revisiting Surface Enhanced Raman  Scattering on Flat Metallic Surfaces

2021 ◽  
Author(s):  
◽  
Stefan Andreas Meyer
Keyword(s):  
Surface Roughness ◽  
Raman Spectroscopy ◽  
Surface Plasmon ◽  
Research Effort ◽  
Metallic Surfaces ◽  
Sers Substrates ◽  
Quantitative Measurements ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Extreme Sensitivity

<p>Surface enhanced Raman spectroscopy (SERS) is undoubtedly a powerful tool as it allows one to overcome the major disadvantage of Raman spectroscopy: the weakness of its signal. Enhancement factors (EF) of up to 1010 make it even possible to detect single molecules. However, using it as an analytical tool to make reproducible, quantitative measurements has so far been difficult as the enhancement of the signal is "bought" at the expense of reproducibility: The larger the EF the more the reproducibility of the substrate suffers. This has been dubbed informally the "SERS uncertainty principle" by Natan [1]. While currently a lot of research effort is taking place at the high-EF-side of the spectrum and ever more sophisticated SERS substrates are being explored, in this thesis we would like to make a shift in paradigm and revisit SERS on flat metallic surfaces, which arguably constitute the simplest substrates available. To this end we will show their usefulness in making quantitative measurements and how they are an ideal platform for a new hybrid technique that combines reproducibility and extreme sensitivity with substantial EFs. For making quantitativemeasurements two examples are explored in a systematic way: in the first example (Chapter 2) the determination of an unknown, resonant Raman cross-section is demonstrated on flat metallic films (possibly with some surface roughness) and confirmed with measurements done on more commonly used SERS substrates. Here the quantitative measurement is made possible by introducing a reference molecule as a standard and having statistics as our main ally: even though we do not know the exact EF that the individual molecules experience on the various substrates, we know that on average both, the unknown sample and the known reference, experience the same. In the second example (Chapter 3) we use commercially available flat films for which we verify experimentally that surface roughness is irrelevant. By themselves these substrates yield no enhancement – in fact they even quench the Raman signal. Yet they allow us to calculate and control the electric field on the surface which enables us to determine the orientation of adsorbed molecules by using surface selection rules (SSR). While the first example is mostly empirical, the second one allows us to test our theoretical understanding of plasmonic systems with proper numerical calculations that are in excellent agreement with the observed data. Finally, in Chapter 4, we use those flat films in a special configuration (called the Kretschmann configuration) to excite Surface Plasmon-Polaritons (SPP). This not only allows us to combine the spatial homogeneity of a flat surface with useful EFs easily predicted fromtheory but also to combine the extreme sensitivity of surface plasmon resonance spectroscopy (SPRS) with the analytical power of SERS. It is not our intention to claim that the work presented here is the first attempt to do analytical work with SERS. Rather the newmethods presented in this thesis will add new strategies and tools to the current research effort while the detailed analysis will provide the means to understand them theoretically and in their historical context.</p>

scholarly journals Revisiting Surface Enhanced Raman  Scattering on Flat Metallic Surfaces

2021 ◽  
Author(s):  
◽  
Stefan Andreas Meyer
Keyword(s):  
Surface Roughness ◽  
Raman Spectroscopy ◽  
Surface Plasmon ◽  
Research Effort ◽  
Metallic Surfaces ◽  
Sers Substrates ◽  
Quantitative Measurements ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Extreme Sensitivity

<p>Surface enhanced Raman spectroscopy (SERS) is undoubtedly a powerful tool as it allows one to overcome the major disadvantage of Raman spectroscopy: the weakness of its signal. Enhancement factors (EF) of up to 1010 make it even possible to detect single molecules. However, using it as an analytical tool to make reproducible, quantitative measurements has so far been difficult as the enhancement of the signal is "bought" at the expense of reproducibility: The larger the EF the more the reproducibility of the substrate suffers. This has been dubbed informally the "SERS uncertainty principle" by Natan [1]. While currently a lot of research effort is taking place at the high-EF-side of the spectrum and ever more sophisticated SERS substrates are being explored, in this thesis we would like to make a shift in paradigm and revisit SERS on flat metallic surfaces, which arguably constitute the simplest substrates available. To this end we will show their usefulness in making quantitative measurements and how they are an ideal platform for a new hybrid technique that combines reproducibility and extreme sensitivity with substantial EFs. For making quantitativemeasurements two examples are explored in a systematic way: in the first example (Chapter 2) the determination of an unknown, resonant Raman cross-section is demonstrated on flat metallic films (possibly with some surface roughness) and confirmed with measurements done on more commonly used SERS substrates. Here the quantitative measurement is made possible by introducing a reference molecule as a standard and having statistics as our main ally: even though we do not know the exact EF that the individual molecules experience on the various substrates, we know that on average both, the unknown sample and the known reference, experience the same. In the second example (Chapter 3) we use commercially available flat films for which we verify experimentally that surface roughness is irrelevant. By themselves these substrates yield no enhancement – in fact they even quench the Raman signal. Yet they allow us to calculate and control the electric field on the surface which enables us to determine the orientation of adsorbed molecules by using surface selection rules (SSR). While the first example is mostly empirical, the second one allows us to test our theoretical understanding of plasmonic systems with proper numerical calculations that are in excellent agreement with the observed data. Finally, in Chapter 4, we use those flat films in a special configuration (called the Kretschmann configuration) to excite Surface Plasmon-Polaritons (SPP). This not only allows us to combine the spatial homogeneity of a flat surface with useful EFs easily predicted fromtheory but also to combine the extreme sensitivity of surface plasmon resonance spectroscopy (SPRS) with the analytical power of SERS. It is not our intention to claim that the work presented here is the first attempt to do analytical work with SERS. Rather the newmethods presented in this thesis will add new strategies and tools to the current research effort while the detailed analysis will provide the means to understand them theoretically and in their historical context.</p>

scholarly journals Strong Dependence of Surface Enhanced Raman Scattering on Structure of Graphene Oxide Film

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1199 ◽  
Author(s):  
Ling Wang ◽  
Yan Zhang ◽  
Yongqiang Yang ◽  
Jing Zhang
Keyword(s):  
Graphene Oxide ◽  
Raman Scattering ◽  
Surface Enhanced Raman Scattering ◽  
Dye Molecules ◽  
Sers Substrates ◽  
Sers Enhancement ◽  
Surface Enhanced ◽  
Enhancement Factors ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Graphene and its derivatives have been demonstrated to be good surface-enhanced Raman scattering (SERS) substrates. However, the literature offers some contrasting views on the SERS effect of graphene-based materials. Thus, understanding the mechanism of the SERS enhancement of graphene is essential for exploring its application as a SERS substrate. In this study, graphene oxide (GO) and chemically reduced graphene oxide (CRGO) films with different morphologies and structures were prepared and applied as SERS substrates to detect Raman dye molecules. The observed enhancement factors can be as large as 10~103. The mechanism of SERS enhancement is discussed. It is shown that the SERS effect was independent of the adsorption of dye molecules and the surface morphologies of graphene-based films. Raman shifts are observed and are almost the same on different graphene-based films, indicating the existence of charge transfer between dye molecules and substrates. The Raman enhancement factors and sensitivities of dye molecules on different films are consistently within the IG/ID ratios of graphene-based substrates, indicating that the dramatically enhanced Raman spectra on graphene-based films are strongly dependent on the average size of sp2 carbon domain.

scholarly journals Controlling surface morphology and sensitivity of granular and porous silver films for surface-enhanced Raman scattering, SERS

2018 ◽  
Vol 9 ◽  
pp. 2813-2831 ◽  
Author(s):  
Sherif Okeil ◽  
Jörg J Schneider
Keyword(s):  
Electron Microscopy ◽  
Large Scale ◽  
Treatment Time ◽  
Low Cost ◽  
Silver Films ◽  
X Ray ◽  
Sers Substrates ◽  
Surface Enhanced ◽  
Enhancement Factors ◽  
Surface Enhanced Raman

The design of efficient substrates for surface-enhanced Raman spectroscopy (SERS) for large-scale fabrication at low cost is an important issue in further enhancing the use of SERS for routine chemical analysis. Here, we systematically investigate the effect of different radio frequency (rf) plasmas (argon, hydrogen, nitrogen, air and oxygen plasma) as well as combinations of these plasmas on the surface morphology of thin silver films. It was found that different surface structures and different degrees of surface roughness could be obtained by a systematic variation of the plasma type and condition as well as plasma power and treatment time. The differently roughened silver surfaces act as efficient SERS substrates showing greater enhancement factors compared to as prepared, sputtered, but untreated silver films when using rhodamine B as Raman probe molecule. The obtained roughened silver films were fully characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron (XPS and Auger) and ultraviolet–visible spectroscopy (UV–vis) as well as contact angle measurements. It was found that different morphologies of the roughened Ag films could be obtained under controlled conditions. These silver films show a broad range of tunable SERS enhancement factors ranging from 1.93 × 102 to 2.35 × 105 using rhodamine B as probe molecule. The main factors that control the enhancement are the plasma gas used and the plasma conditions, i.e., pressure, power and treatment time. Altogether this work shows for the first time the effectiveness of a plasma treatment for surface roughening of silver thin films and its profound influence on the interface-controlled SERS enhancement effect. The method can be used for low-cost, large-scale production of SERS substrates.

Numerical techniques of the estimation the amount of waveguides surface roughness for the THz regime

2021 ◽  
Author(s):  
N.V. Fedorkova ◽  
A.A. Sultanshin
Keyword(s):  
Surface Roughness ◽  
Effective Conductivity ◽  
Numerical Technique ◽  
Field Enhancement ◽  
Skin Depth ◽  
Efficient Design ◽  
Numerical Techniques ◽  
Full Wave ◽  
Direct Measurements ◽  
Enhancement Factors

The article is devoted to the problem of the efficient design of THz waveguides devices. Extreme small sizes of THz devices such as subharmonic pumped mixers for radiometer witch waveguides are integrated in copper block covered with 3 μm gold are presented. The three numerical techniques and direct measurements in the THz regime have been used to predict the effective conductivity reduction due to protrusions. Efficient design of THz systems requires the ability to predict effective conductivity, allowing engineers to determine the amount of surface roughness for acceptable reflection losses prior to fabrication. Full-wave numerical technique to predict the field enhancement factors for both the rf electric field and the rf magnetic field on the protrusion above smooth sample in the THz regime has been mentioned. The electric field and magnetic field enhancement factors on the hemispherical protrusion should be excluded in case the protrusions size are smaller than δ/50 and δ/1.5 correspondingly (δ is skin depth). Mie-Scattering-based approach approximates a unit cell of the grating as a circular cylinder protrusion the additional loss due to the protrusion compared with a perfectly flat surface of the same material. Hammerstad–Bekkadal Model demonstrates an analytical function which depends of sheet resistance for a sample with surface roughness on the surface roughness and skin depth of the metal. Numerical calculations using this technique predict 10% power absorption due to surface features 35 nm at 400 GHz. A layout of the apparatus for direct measurements of the effective conductivity of samples with roughness features using an open quasi-optical resonator is given. The results of theoretical calculation and empirical evaluation have been compared with computer simulation software taking into consideration of the effective conductivity only due to the change in the surface geometry. The comparison empirical results and numerical calculations full-wave numerical technique are more accurate for samples that are smooth relative to the skin depth. For surface features greater than the skin depth, we found the Hammerstad and Bekkadal model to be a better. The observed methods can be used as a rapid means to estimate waveguides surface roughness in terms of power loss in the THz regime.

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