Label-Free Nanometer-Resolution Imaging of Biological Architectures through Surface Enhanced Raman Scattering

Ayas, Sencer; Çınar, Göksu; Özkan, Alper D.; Soran, Zeliha; Ekiz, Oner; Kocaay, D.; Tomak, Aysel; Toren, Pelin; Kaya, Yasin; Tunç, İlknur; Zareie, Hadi M.; Tekinay, Turgay; Tekinay, Ayşe B.; Güler, Mustafa O.; Dâna, Aykutlu

doi:10.1038/srep02624

Cited by 64 publications

(67 citation statements)

References 47 publications

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“…As shown in Figure 2 c, the intensities at 1013 ± 3, 1200 ± 3, and 1636 ± 3 cm −1 peaks were measured and normalized with the mean value. According to the statistical analysis, the standard deviation, σ , for all diffraction-limit pixels in the 20 µm × 20 µm area is 21.6%-22.7%, which is reasonably good compared with other random particle based SERS substrates [ 25,26 ] or hierarchical porous structures. [ 18,53 ] Although excellent variation smaller than 10% have been obtained using top-down nanofabrication methods, [54][55][56] the large area low cost fabrication and ultrabroadband response is the advantage of the proposed metasurface substrate.…”

Section: Resultsmentioning

confidence: 91%

See 1 more Smart Citation

Ultrabroadband Metasurface for Efficient Light Trapping and Localization: A Universal Surface‐Enhanced Raman Spectroscopy Substrate for “All” Excitation Wavelengths

Zhang

Liu

et al. 2015

Adv Materials Inter

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nanoporous lithography methods, [18][19][20][21] etc. However, these techniques are still expensive and complicated for the fabrication of high quality SERS substrates over large areas, thus resulting in high prices for commercial SERS substrates. Furthermore, most commercial SERS substrates can only work for individual excitation wavelengths, i.e., one particular product works at one or two excitation wavelengths only. [22][23][24][25][26][27][28] When one wants to identify anonymous trace molecules or mixed samples, multiple excitation wavelengths will be required. [29][30][31] In this case, different substrates have to be used for different wavelength excitation, which consumes more biological/chemical materials, substrates, and measurement time. This is an obvious disadvantage for conventional SERS substrates. On the contrary, the SERS EF is proportional to the product of the fi eld intensity enhancements at both excitation and Raman scattering wavelengths. It was predicted that the maximum SERS enhancement can be achieved when localized surface plasmon resonance is located between the excitation and Raman scattering wavelengths. [ 32 ] To realize higher EF, double-resonance SERS substrates were proposed to realize strong enhancements for excitation and Raman scattered signals simultaneously using expensive e-beam lithography processes. [ 23 ] Due to the narrowband absorption spectra for both resonant bands, the enhanced SERS signal is still limited within narrow spectral regions. To address this problem, broadband resonant nanostructures are highly desired. For instance, a relatively broadband 1D metal-dielectric-metal metasurface (i.e., ≈70% optical absorption from 420 to 550 nm) was fabricated using e-beam lithography to realize uniform enhancement for SERS sensing. [ 24 ] However, the top-down lithography technique imposed a signifi cant fabrication cost barrier for large-scale practical applications. In addition, 1D grating structures are polarization dependent which can only work for given polarization states (usually transverse magnetic polarization). To overcome these limitations, here we report an ultrabroadband super absorbing metasurface substrate that can enhance the SERS signal for excitation wavelengths in a broad spectral region using lithography-free processes. [ 33 ] Most frequently used excitation wavelengths for SERS (e.g., from 450 to 1100 nm [23][24][25][26][27][28]34 ] are all covered due to the broadband light trapping and fi eld concentration within deep subwavelength Most reported surface-enhanced Raman spectroscopy (SERS) substrates can work for individual excitation wavelengths only. Therefore, different substrates have to be used for different excitation wavelengths, which consumes more biological/chemical materials, substrates, and measurement time. Here, an ultrabroadband super absorbing metasurface that can work as a universal substrate for low cost and high performance SERS sensing is reported. Due to broadband light trapping and localized fi eld enhancement, this structure can...

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Section: Resultsmentioning

confidence: 91%

“…[ 25,26,33 ] The nominal mass thickness of the directly deposited fi lm is 9.1 nm. The sample was thermally annealed at 120 °C under the nitrogen ambient (see the Experimental Section for more fabrication details).…”

Section: Resultsmentioning

confidence: 99%

Ultrabroadband Metasurface for Efficient Light Trapping and Localization: A Universal Surface‐Enhanced Raman Spectroscopy Substrate for “All” Excitation Wavelengths

Zhang

Liu

et al. 2015

Adv Materials Inter

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“…A thin Ag layer of 3 nm mass thickness is evaporated on the HfO 2 , which forms Ag nanoislands of average diameter of 30 nm and thickness of 10 nm. 21,22 The surface exhibits a broad plasmonic absorption band around 580 nm (Figure 3(b)) and a repeatable photoresponse as measured by XPS, as shown in Figures 3(c) and 3(d). When a semicontinuous film is formed on top of HfO 2 by depositing 5 nm thick Ag, no photoresponse can be observed (Figures 3(e)-3(h)).…”

Section: -2mentioning

confidence: 87%

Probing hot-electron effects in wide area plasmonic surfaces using X-ray photoelectron spectroscopy

Ayas

Cupallari

Dâna

2014

Applied Physics Letters

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Plasmon enhanced hot carrier formation in metallic nanostructures increasingly attracts attention due to potential applications in photodetection, photocatalysis, and solar energy conversion. Here, hot-electron effects in nanoscale metal-insulator-metal (MIM) structures are investigated using a non-contact X-ray photoelectron spectroscopy based technique using continuous wave X-ray and laser excitations. The effects are observed through shifts of the binding energy of the top metal layer upon excitation with lasers of 445, 532, and 650 nm wavelength. The shifts are polarization dependent for plasmonic MIM grating structures fabricated by electron beam lithography. Wide area plasmonic MIM surfaces fabricated using a lithography free route by the dewetting of evaporated Ag on HfO2 exhibit polarization independent optical absorption and surface photovoltage. Using a simple model and making several assumptions about the magnitude of the photoemission current, the responsivity and external quantum efficiency of wide area plasmonic MIM surfaces are estimated as 500 nA/W and 11 × 10−6 for 445 nm illumination.

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“…The sensitivity can be improved greatly by combining SNOM with other techniques such as coherent anti-Stokes Raman scattering (CARS), stimulated Raman scattering [25], or tip enhanced Raman scattering (TERS) [26]. More recently surface enhanced Raman scattering (SERS) has demonstrated label-free single molecule resolution [18,27]. Coupling Raman spectroscopy with c-SNOM systems overcomes the limitations of the other sensitivity enhancing techniques and can achieve nanoscale-SNOM enhanced Raman spectroscopy [17].…”

Section: C-snom Spectroscopymentioning

confidence: 99%

A Review of Three-Dimensional Scanning Near-Field Optical Microscopy (3D-SNOM) and Its Applications in Nanoscale Light Management

2017

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Abstract:In this article, we present an overview of aperture and apertureless type scanning near-field optical microscopy (SNOM) techniques that have been developed, with a focus on three-dimensional (3D) SNOM methods. 3D SNOM has been undertaken to image the local distribution (within~100 nm of the surface) of the electromagnetic radiation scattered by random and deterministic arrays of metal nanostructures or photonic crystal waveguides. Individual metal nanoparticles and metal nanoparticle arrays exhibit unique effects under light illumination, including plasmon resonance and waveguiding properties, which can be directly investigated using 3D-SNOM. In the second part of this article, we will review a few applications in which 3D-SNOM has proven to be useful for designing and understanding specific nano-optoelectronic structures. Examples include the analysis of the nano-optical response phonetic crystal waveguides, aperture antennae and metal nanoparticle arrays, as well as the design of plasmonic solar cells incorporating random arrays of copper nanoparticles as an optical absorption enhancement layer, and the use of 3D-SNOM to probe multiple components of the electric and magnetic near-fields without requiring specially designed probe tips. A common denominator of these examples is the added value provided by 3D-SNOM in predicting the properties-performance relationship of nanostructured systems.

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Label-Free Nanometer-Resolution Imaging of Biological Architectures through Surface Enhanced Raman Scattering

Cited by 64 publications

References 47 publications

Ultrabroadband Metasurface for Efficient Light Trapping and Localization: A Universal Surface‐Enhanced Raman Spectroscopy Substrate for “All” Excitation Wavelengths

Ultrabroadband Metasurface for Efficient Light Trapping and Localization: A Universal Surface‐Enhanced Raman Spectroscopy Substrate for “All” Excitation Wavelengths

Probing hot-electron effects in wide area plasmonic surfaces using X-ray photoelectron spectroscopy

A Review of Three-Dimensional Scanning Near-Field Optical Microscopy (3D-SNOM) and Its Applications in Nanoscale Light Management

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