scholarly journals Plasma Fabrication and SERS Functionality of Gold Crowned Silicon Submicrometer Pillars

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1244 ◽  
Author(s):  
Paola Pellacani ◽  
Carlo Morasso ◽  
Silvia Picciolini ◽  
Dario Gallach ◽  
Lucia Fornasari ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Surface Enhanced Raman Spectroscopy ◽  
Post Processing ◽  
Advanced Material ◽  
X Ray ◽  
Colloidal Monolayer ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Lift Off ◽  
X Ray Absorption

Sequential plasma processes combined with specific lithographic methods allow for the fabrication of advanced material structures. In the present work, we used self-assembled colloidal monolayers as lithographic structures for the conformation of ordered Si submicrometer pillars by reactive ion etching. We explored different discharge conditions to optimize the Si pillar geometry. Selected structures were further decorated with gold by conventional sputtering, prior to colloidal monolayer lift-off. The resulting structures consist of a gold crown, that is, a cylindrical coating on the edge of the Si pillar and a cavity on top. We analysed the Au structures in terms of electronic properties by using X-ray absorption spectroscopy (XAS) prior to and after post-processing with thermal annealing at 300 °C and/or interaction with a gold etchant solution (KI). The angular dependent analysis of the plasmonic properties was studied with Fourier transformed UV-vis measurements. Certain conditions were selected to perform a surface enhanced Raman spectroscopy (SERS) evaluation of these platforms with two model dyes, prior to confirming the potential interest for a well-resolved analysis of filtered blood plasma.

Characterization of the Adsorption of Nucleic Acid Bases onto Ferrihydrite via Fourier Transform Infrared and Surface-Enhanced Raman Spectroscopy and X-ray Diffractometry

Astrobiology ◽  
2015 ◽  
Vol 15 (9) ◽  
pp. 728-738 ◽  
Author(s):  
José E. Canhisares-Filho ◽  
Cristine E.A. Carneiro ◽  
Henrique de Santana ◽  
Alexandre Urbano ◽  
Antonio C.S. da Costa ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Fourier Transform ◽  
Nucleic Acid ◽  
Fourier Transform Infrared ◽  
Surface Enhanced Raman Spectroscopy ◽  
Nucleic Acid Bases ◽  
X Ray ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

HIGH-ORDERED AND ULTRA-SENSITIVE PARTICLE-IN-BOWL METALLIC ARRAYS FOR SURFACE ENHANCED RAMAN SPECTROSCOPY

NANO ◽  
2014 ◽  
Vol 09 (04) ◽  
pp. 1450050 ◽  
Author(s):  
DI DI ◽  
PEITAO DONG ◽  
CHAOGUANG WANG ◽  
JIAN CHEN ◽  
JUNFENG WANG ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Fdtd Method ◽  
Disease Diagnosis ◽  
Surface Enhanced Raman Spectroscopy ◽  
Excitation Wavelength ◽  
Raman Enhancement ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Em Field ◽  
Lift Off

High-ordered particle-in-bowl (PIB) arrays are developed in this paper for surface enhanced Raman spectroscopy (SERS). A heterogeneous shadow mask, composing of the chrome (Cr) layer and colloid residues, is used to fabricate the silicon ( Si ) template from where the PIB arrays finally lift-off. The finite difference time domain (FDTD) method is employed to investigate the Raman enhancement mechanism of this PIB architecture. The electromagnetic (EM) field tends to concentrate in the gap between the bowl and the particle forming the "hot spots". The enhancement factor (EF) of the EM field is about 70 with an excitation wavelength of 785 nm. The Raman measurements validate the EM calculation of the PIB arrays. The EF is about 1.12 × 107 using Rodamine 6G (R6G) as probe molecule. The proposed PIB array is high-ordered in morphology and ultra-sensitive in Raman measurement, providing an ideal substrate for SERS-based bio-chemical sensing, disease diagnosis and analytical chemistry.

scholarly journals Towards a traceable enhancement factor in surface-enhanced Raman spectroscopy

2020 ◽  
Vol 8 (46) ◽  
pp. 16513-16519
Author(s):  
Eleonora Cara ◽  
Luisa Mandrile ◽  
Alessio Sacco ◽  
Andrea M. Giovannozzi ◽  
Andrea M. Rossi ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Surface Density ◽  
Enhancement Factor ◽  
Surface Enhanced Raman Spectroscopy ◽  
Molecular Surface ◽  
X Ray ◽  
Sers Enhancement ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

Determination of the SERS enhancement factor through the challenging measurement of the molecular surface density by reference-free X-ray fluorescence.

scholarly journals Porous Hybrids Structure between Silver Nanoparticle and Layered Double Hydroxide for Surface-Enhanced Raman Spectroscopy

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 447
Author(s):  
Su-Bin Lee ◽  
Seung-Min Paek ◽  
Jae-Min Oh
Keyword(s):  
Raman Spectroscopy ◽  
Metal Oxide ◽  
Calcination Temperature ◽  
Layered Double Hydroxide ◽  
Silver Nanoparticle ◽  
Surface Enhanced Raman Spectroscopy ◽  
X Ray ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Double Hydroxide

Silver nanoparticle (AgNP), in terms of antibacterial, catalytic, electronic, and optical applications, is an attractive material. Especially, when prepared to furnish sharp edge and systematic particle orientation on the substrate, AgNPs can take advantage of surface-enhanced Raman spectroscopy (SERS). In this research, we suggested a synthetic method to immobilize the AgNP on metal oxide by utilizing Ag-thiolate and layered double hydroxide (LDH) as precursor and template, respectively. The layer-by-layer structure of LDH and Ag-thiolate transformed through reductive calcination to metal oxide and AgNP array. Physicochemical characterization, including powder X-ray diffraction, N2 adsorption–desorption, microscopies, and X-ray photoelectron spectroscopy, revealed that the AgNP with sufficient crystallinity and particle gap was obtained at relatively high calcination temperature, ~600 °C. UV-vis diffusion reflectance spectroscopy showed that the calcination temperature affected particle size and electronic structure of AgNP. The prepared materials were subjected to SERS tests toward 4-nitrothiophenol (4-NTP). The sample obtained at 600 °C exhibited 50 times higher substrate enhancement factor (SEF) than the one obtained at 400 °C, suggesting that the calcination temperature was a determining parameter to enhance SERS activity in current synthetic condition.

Bacterial detection and differentiation via direct volatile organic compound sensing with surface enhanced Raman spectroscopy

2017 ◽  
Author(s):  
Caitlin S. DeJong ◽  
David I. Wang ◽  
Aleksandr Polyakov ◽  
Anita Rogacs ◽  
Steven J. Simske ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Bacterial Infections ◽  
Direct Detection ◽  
Point Of Care ◽  
Surface Enhanced Raman Spectroscopy ◽  
E Coli ◽  
Recent Emergence ◽  
Surface Enhanced ◽  
Volatile Organic ◽  
Surface Enhanced Raman

Through the direct detection of bacterial volatile organic compounds (VOCs), via surface enhanced Raman spectroscopy (SERS), we report here a reconfigurable assay for the identification and monitoring of bacteria. We demonstrate differentiation between highly clinically relevant organisms: <i>Escherichia coli</i>, <i>Enterobacter cloacae</i>, and <i>Serratia marcescens</i>. This is the first differentiation of bacteria via SERS of bacterial VOC signatures. The assay also detected as few as 10 CFU/ml of <i>E. coli</i> in under 12 hrs, and detected <i>E. coli</i> from whole human blood and human urine in 16 hrs at clinically relevant concentrations of 10<sup>3</sup> CFU/ml and 10<sup>4</sup> CFU/ml, respectively. In addition, the recent emergence of portable Raman spectrometers uniquely allows SERS to bring VOC detection to point-of-care settings for diagnosing bacterial infections.

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