Plasmon energy shift in porous silicon measured by x-ray photoelectron spectroscopy

2001 ◽  
Vol 79 (26) ◽  
pp. 4432-4434 ◽  
Author(s):  
N. Mannella ◽  
G. Gabetta ◽  
F. Parmigiani
Keyword(s):  
Porous Silicon ◽  
Photoelectron Spectroscopy ◽  
Energy Shift ◽  
Plasmon Energy ◽  
X Ray

Gold nanoclusters reductively deposited on porous silicon: morphology and electronic structures

1998 ◽  
Vol 76 (11) ◽  
pp. 1707-1716 ◽  
Author(s):  
I Coulthard ◽  
S Degen ◽  
Y -J Zhu ◽  
T K Sham
Keyword(s):  
Gold Nanoparticles ◽  
Porous Silicon ◽  
Photoelectron Spectroscopy ◽  
Gold Nanoclusters ◽  
Gold Complex ◽  
X Ray Diffraction ◽  
Complex Ions ◽  
X Ray ◽  
Preparation Conditions ◽  
P Type

Utilizing porous silicon as a reducing agent and a substrate, gold complex ions [AuCl4]- were reduced from aqueous solution to produce nanoparticles of gold upon the surface of porous silicon. Scanning electron microscopy (SEM) was utilized to study the morphology of the porous silicon layers and the deposits of gold nanoparticles. It is found that preparation conditions have a profound effect on the morphology of the deposits, especially on porous silicon prepared from a p-type wafer. The gold nanoparticles, varying from micrometric aggregates of clusters of the order of 10 nm, to a distribution of nearly spherical clusters of the order of 10 nm, to strings of ~10 nm were observed and compared to bulk gold metal using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS). These techniques confirm and complement the SEM findings. The potential for this reductive deposition technique is noted.Key words: gold nanostructures, reductive deposition, porous silicon, morphology, X-ray spectroscopy.

scholarly journals Porous Silicon-Zinc Oxide Nanocomposites Prepared by Atomic Layer Deposition for Biophotonic Applications

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1987 ◽  
Author(s):  
Mykola Pavlenko ◽  
Valerii Myndrul ◽  
Gloria Gottardi ◽  
Emerson Coy ◽  
Mariusz Jancelewicz ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Optical Properties ◽  
Porous Silicon ◽  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Atomic Layer ◽  
Visible Range ◽  
Optical Biosensing ◽  
X Ray ◽  
Layer Deposition

In the current research, a porous silicon/zinc oxide (PSi/ZnO) nanocomposite produced by a combination of metal-assisted chemical etching (MACE) and atomic layer deposition (ALD) methods is presented. The applicability of the composite for biophotonics (optical biosensing) was investigated. To characterize the structural and optical properties of the produced PSi/ZnO nanocomposites, several studies were performed: scanning and transmission electron microscopy (SEM/TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), diffuse reflectance, and photoluminescence (PL). It was found that the ALD ZnO layer fully covers the PSi, and it possesses a polycrystalline wurtzite structure. The effect of the number of ALD cycles and the type of Si doping on the optical properties of nanocomposites was determined. PL measurements showed a “shoulder-shape” emission in the visible range. The mechanisms of the observed PL were discussed. It was demonstrated that the improved PL performance of the PSi/ZnO nanocomposites could be used for implementation in optical biosensor applications. Furthermore, the produced PSi/ZnO nanocomposite was tested for optical/PL biosensing towards mycotoxins (Aflatoxin B1) detection, confirming the applicability of the nanocomposites.

Near ambient pressure X-ray photoelectron spectroscopy monitoring of the surface immobilization cascade on a porous silicon-gold nanoparticle FET biosensor

2019 ◽  
Vol 492 ◽  
pp. 362-368 ◽  
Author(s):  
Chloé Rodriguez ◽  
Paul Dietrich ◽  
Vicente Torres-Costa ◽  
Virginia Cebrián ◽  
Cristina Gómez-Abad ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Gold Nanoparticle ◽  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
Surface Immobilization ◽  
X Ray

Synthesis of Nanophase Noble Metal Systems Utilizing Porous Silicon

1996 ◽  
Vol 457 ◽  
Author(s):  
I. Coulthard ◽  
T. K. Sham
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Porous Silicon ◽  
Noble Metal ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Visible Range ◽  
X Ray ◽  
Metallic Salt ◽  
Scanning Electron

ABSTRACTApart from its well known ability to luminesce very intensely at room temperature in the visible range, porous silicon is also an effective reducing agent. We report the formation of several noble metal (Pd, Ag, Au, Pt) nanostructures by reductive dispersion of metal ions from aqueous solutions onto the surface of porous silicon. The nanophase systems produced by reductive deposition vary with the element deposited and the metallic salt utilized in the process. The resulting nanophase systems were studied using a variety of techniques including: scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and spectroscopie methods using synchrotron radiation.

scholarly journals Mesoporous CdO/Al2O3 nanocomposite with enhanced optoelectronic properties for visible-light photocatalysis and bactericidal applications

2021 ◽  
Author(s):  
Janani B ◽  
Asad Syed ◽  
Abdallah M. Elgorban ◽  
Ali H. Bahkali ◽  
S. Sudheer Khan
Keyword(s):  
Photoelectron Spectroscopy ◽  
Organic Contaminants ◽  
Dye Degradation ◽  
High Surface ◽  
High Surface Area ◽  
Energy Shift ◽  
Band Gap Energy ◽  
Oh Radicals ◽  
X Ray ◽  
Viable Solution

Abstract Pristine Al2O3 and CdO are known to possess poor photocatalytic activity individually. The formation of CdO/Al2O3 heterojunction was investigated for the enhancement of photocatalytic performance. High resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) has been used to determine the crystalline feature and elemental composition of the NCs respectively. Peaks ascribed to Cd-O and O-Al-O was noted in fourier-transform infrared spectroscopy (FTIR) analysis. The NCs exhibits a high surface area (27.23 m2/g) to their contributing particles which was analysed using BET analyser. The band gap energy of CdO/Al2O3NCs was observed to be 2.95 eV which shows a considerable energy shift from its individual particles, CdO (2.73 eV) and Al2O3 (3.94 eV). The results displayed that the degradation efficiency of the CdO-Al2O3 NCs was enhanced 14 times than pristine Al2O3 and 3.5 times than pristine CdO. The MB dye has showed the half life period of 80 min. TOC analysis of degraded product supported high mineralization of the pollutants. The dye degradation was driven by OH. radicals and the CdO-Al2O3 nanocomposite possessed high reusability which was confirmed by six cycle test. Growth inhibition of E. coli, P. aeruginosa and B. subtilis was attained by exposure to CdO/Al2O3 NCs. The CdO-Al2O3 NCs can be a viable solution for degradation of organic contaminants effectively under natural sun light as well as an efficient antibacterial agent.

scholarly journals In situ metalation of free base phthalocyanine covalently bonded to silicon surfaces

2014 ◽  
Vol 5 ◽  
pp. 2222-2229 ◽  
Author(s):  
Fabio Lupo ◽  
Cristina Tudisco ◽  
Federico Bertani ◽  
Enrico Dalcanale ◽  
Guglielmo G Condorelli
Keyword(s):  
Porous Silicon ◽  
Photoelectron Spectroscopy ◽  
Relevant Information ◽  
Silicon Surfaces ◽  
Porous Si ◽  
Wet Chemistry ◽  
X Ray ◽  
Covalently Bonded ◽  
Phthalocyanine Ring

Free 4-undecenoxyphthalocyanine molecules were covalently bonded to Si(100) and porous silicon through thermic hydrosilylation of the terminal double bonds of the undecenyl chains. The success of the anchoring strategy on both surfaces was demonstrated by the combination of X-ray photoelectron spectroscopy with control experiments performed adopting the commercially available 2,3,9,10,16,17,23,24-octakis(octyloxy)-29H,31H-phthalocyanine, which is not suited for silicon anchoring. Moreover, the study of the shape of the XPS N 1s band gave relevant information on the interactions occurring between the anchored molecules and the substrates. The spectra suggest that the phthalocyanine ring interacts significantly with the flat Si surface, whilst ring–surface interactions are less relevant on porous Si. The surface-bonded molecules were then metalated in situ with Co by using wet chemistry. The efficiency of the metalation process was evaluated by XPS measurements and, in particular, on porous silicon, the complexation of cobalt was confirmed by the disappearance in the FTIR spectra of the band at 3290 cm−1 due to –NH stretches. Finally, XPS results revealed that the different surface–phthalocyanine interactions observed for flat and porous substrates affect the efficiency of the in situ metalation process.

scholarly journals Synthesis and Introducing Au-Cu Alloy Nanoparticles/Porous Silicon as a Novel Modifier of Screen Printed Carbon Electrode in Simultaneous Electrocatalytic Detection of Codeine and Acetaminophen

2022 ◽  
Author(s):  
Farzad Allahnouri ◽  
Khalil Farhadi ◽  
Hamideh Imanzadeh ◽  
Rahim Molaei ◽  
Habibollah Eskandari
Keyword(s):  
Porous Silicon ◽  
Photoelectron Spectroscopy ◽  
High Surface ◽  
High Surface Area ◽  
Galvanic Replacement ◽  
Human Blood Plasma ◽  
Carbon Electrode ◽  
X Ray ◽  
Screen Printed Carbon Electrode ◽  
Screen Printed

Abstract In the present study, a bimetallic nanostructure of gold-copper (Au-CuNPs) was decorated on the surface of porous silicon (PSi) using an easy galvanic replacement reaction between metal ions and PSi in the presence of 0.1 M hydrofluoric acid solution. The morphology and structures of the Au-CuNPs@PSi nanocomposite were characterized using X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) energy-dispersive X-ray spectroscopy (EDX) and cyclic voltammetry (CV) techniques. Then, prepared nanocomposite was used as a modifier in screen-printed carbon electrode (SPCE) for the highly sensitive simultaneous determination of codeine (COD) and acetaminophen (ACE). The combination of PSi and metals nanoparticles provide a porous and high surface area with excellent electrical conductivity which leads to reduce the peak potentials and enhance the oxidation peak currents of COD and ACE at the surface of the Au-CuNPs@PSi/SPCE nanosensor. The dynamic linear ranges were obtained from 0.06 to 0.6 µM for both COD and ACE and the detection limits (3.0 S/N) estimated 0.35 µM for COD and 0.30 µM for ACE, respectively. Moreover, recovery tests were carried out in real samples such as urine, human blood plasma, and tablets.

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