Visible Luminescence from Surface-Oxidized Silicon Nanostructures: Three Region Model

1995 ◽  
Vol 405 ◽  
Author(s):  
Yoshihiko Kanemitsu
Keyword(s):  
Surface Layer ◽  
Essential Role ◽  
Interface State ◽  
Luminescence Properties ◽  
Silicon Nanostructures ◽  
Visible Luminescence ◽  
Region Model ◽  
Disorder Potential ◽  
Si Nanostructures ◽  
Red Luminescence

AbstractWe discuss the mechanism of red luminescence from surface-oxidized Si nanostructures. The interface state between crystalline Si and SiO2 surface layer plays an essential role in efficient visible luminescence. The crystalline Si nanostructures with a disorder potential of interface states show complicated luminescence properties.

scholarly journals Three-dimensional self-assembled hybrid silicon nanostructures for high sensitivity SERS chemical and biosensing applications

2021 ◽  
Author(s):  
Jeffery Alexander Powell
Keyword(s):  
Noble Metal ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Metal Nanostructures ◽  
Silicon Nanostructures ◽  
Sers Enhancement ◽  
Noble Metal Nanostructures ◽  
Self Assembled ◽  
Hybrid Silicon ◽  
Si Nanostructures

Raman spectroscopy is a powerful tool for detection of chemical and bioanalytes but lacks enhancement required to detect these analytes at the ultrahigh sensitivity needed for many applications. Surface enhanced Raman Scattering is a technique by which an analyte signal can become greatly enhanced and, near single molecule sensitivity, is achievable. Currently, SERS-based detection platforms currently rely on noble metal nanostructures as primary enhancing sources for the detection of chemical and bioanalytes but have significant limitations in terms of reproducibility and biocompatibility. Recent research has shown that semiconductors have the ability to exhibit SERS enhancing characteristics that can potentially supplant the use of noble metals without the limitations associated with noble metal nanomaterials. This thesis presents, the generation of three-dimensional self-assembled hybrid silicon nanostructures though a laser-ion plume formation mechanism. These Si nanostructures exhibit high sensitivity SERS enhancement characteristics which can be applied for chemical and biosensing applications. In this thesis, the Raman enhancing characteristics of the hybrid Si nanostructures are examined and correlated to the unique physical morphology and material chemistry of these nanostructures. These Si nanostructures are shown to be comprised of individual Si nanospheroids that have fused to form a highly 3D nanoweb-like self-assembled nanostructures. It is also shown that these nanospheroids are composed of both amorphous and polycrystalline sub-regions, which can only be generated within an ion-plume formed by a femtosecond pulsed laser. By programming the laser, the nanostructure morphology and hybrid nature can be manipulated and optimized. These Si nanostructures are shown to be highly sensitive as SERS platforms for chemical analytes. In addition, it is shown that with the application of noble metal nanoparticles on the surface of the 3D hybrid silicon nanowebs structures, an additional enhancement boost can be optimized for the detection of chemical molecules. With this, the dual contribution to the SERS sensitivity from both the primary Si nanostructures and the secondary noble metal nanostructures can be used to detect the presence of a biomolecule analyte is shown. To delve deeper into how these hybrid Si nanostructures cause SERS enhancement of bioanalytes, the Si ion interactions within the laser-ion plume were manipulated to induce quantum-scale defects within the hybrid Si nanospheroids. By creating both an inert and oxygenated laser-ion plumes the formation of sub-nanograins within the nanospheroids and sub-nanovoids on the nanospheroid surface is shown to significantly enhance the detection of bioanalyte signal for multiple biomolecules which act as signals for various diseases. Based on the results in this thesis, it has been proven that Si-based nanostructures have the capacity to be used as sole SERS enhancing sources for chemical and biomolecule analytes.

scholarly journals Deposition of Gold Nanoparticles via Galvanic Replacement in DMSO and Their Influence on Formation of Silicon Nanostructures

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Mariana Shepida ◽  
Orest Kuntyi ◽  
Stepan Nichkalo ◽  
Galyna Zozulya ◽  
Sergiy Korniy
Keyword(s):  
Surface Coverage ◽  
Aprotic Solvent ◽  
Nanowire Arrays ◽  
Silicon Nanostructures ◽  
Galvanic Replacement ◽  
Dmso Solution ◽  
Coverage Density ◽  
Size Growth ◽  
Si Nanostructures ◽  
Deposition Conditions

The process of gold nanoparticle (AuNP) precipitation on the silicon (Si) surface by galvanic replacement (GR) in dimethyl sulfoxide (DMSO) solution depending on the concentration of H[AuCl4], temperature, and duration was investigated. It is established that with an increase in the concentration of [AuCl4]− ions (from 2 to 8 mM H[AuCl4]), both the size of AuNPs and their surface coverage density are increased. It is demonstrated that an increase in temperature causes the size of AuNPs to increase from 40 to 80 nm at 40°C to 80–120 and 120–160 nm at 50 and 60°C, respectively. As the duration of the GR process increases, there is a tendency of the particle size growth. Under the studied deposition conditions, the organic aprotic solvent medium contributes to the formation of spherical AuNPs with 2D substrate filling. It is established that the AuNPs deposited on the silicon surface catalyze the process of metal-assisted chemical etching (MacEtch), which makes it possible to obtain Si nanostructures in the form of nanowire arrays.

UV-visible luminescence properties of the broad-band Yb:CALGO laser crystal

2014 ◽  
Author(s):  
A. Jaffres ◽  
S.K. Sharma ◽  
P. Loiseau ◽  
B. Viana ◽  
J.L. Doualan ◽  
...  
Keyword(s):  
Laser Crystal ◽  
Broad Band ◽  
Luminescence Properties ◽  
Visible Luminescence ◽  
Uv Visible

Synthesis, microstructure and visible luminescence properties of vertically aligned lightly doped porous silicon nanowalls

2019 ◽  
Vol 273 ◽  
pp. 99-106 ◽  
Author(s):  
Anil K. Behera ◽  
R.N. Viswanath ◽  
C. Lakshmanan ◽  
K.K. Madapu ◽  
M. Kamruddin ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Luminescence Properties ◽  
Visible Luminescence ◽  
Vertically Aligned

scholarly journals Оптические и структурные свойства наноструктур Ag и c-Si, формирующихся в процессе металл-стимулированного химического травления кремния

2019 ◽  
Vol 53 (4) ◽  
pp. 576
Author(s):  
Ю.А. Жарова ◽  
В.А. Толмачев ◽  
С.И. Павлов
Keyword(s):  
Optical Model ◽  
Single Crystal Silicon ◽  
Silicon Nanostructures ◽  
Crystal Silicon ◽  
Fitting Procedures ◽  
Stage Process ◽  
Three Stages ◽  
Metal Assisted Chemical Etching ◽  
Si Nanostructures ◽  
Stage 1

AbstractThis study consisting of two parts is concerned with the features of the three-stage process of the metal-assisted chemical etching (MACE) of silicon. This process is used to fabricate silicon nanostructures. In the first part of this work, a layer of self-assembled Ag nanoparticles chemically deposited from a solution on the surface of single-crystal silicon (c-Si) (MACE stage 1) was studied, and the second part includes of investigation of Si nanostructures formed in stages 2 and 3. By means of spectroscopic ellipsometry (in the range of wavelengths λ = 250–900 nm), the pseudodielectric functions of the nanostructures were determined and compared for all the three stages of the MACE process. In addition, for the Si nanostructures, the parameters of layers (the thickness and void fraction) were calculated in the context of the multilayer optical model, with the use of Bruggeman’s effective-medium approximation and fitting procedures.

Controllable silicon nanostructures featuring stable fluorescence and intrinsic in vitro and in vivo anti-cancer activity

2019 ◽  
Vol 7 (40) ◽  
pp. 6247-6256
Author(s):  
Binbin Chu ◽  
Sicong Wu ◽  
Xiaoyuan Ji ◽  
Runzhi Chen ◽  
Bin Song ◽  
...  
Keyword(s):  
Cancer Therapy ◽  
Silicon Nanostructures ◽  
Synthetic Approach ◽  
Microwave Assisted ◽  
Anti Cancer ◽  
Si Nanostructures ◽  
Cancer Activity

A facile microwave-assisted synthetic approach enables the fabrication of different-dimensional Si nanostructures with unique optical merits for cancer therapy.

Control of the Cobalt Surface Layer Formation on Cemented Carbides

2015 ◽  
Vol 825-826 ◽  
pp. 1009-1015
Author(s):  
Alan Pasquazzi ◽  
Wolf Dieter Schubert ◽  
Ronald Weissenbacher
Keyword(s):  
Surface Layer ◽  
Essential Role ◽  
Recent Literature ◽  
Cemented Carbide ◽  
Cemented Carbides ◽  
Layer Formation ◽  
Grain Sizes ◽  
Cooling Conditions ◽  
Microstructure Of The Material ◽  
Surface Layer Formation

The formation of a surface layer of cobalt on cemented carbides which occurs on cooling during sintering is an often observed phenomenon which has been discussed in the recent literature. The presented work shows different factors which influence the formation of the layer and proposes factor-related mechanisms. For this purpose cemented carbide samples with different compositions, WC grain sizes and carbon contents were produced and studied. The results reveal that besides the cooling conditions also the variations in composition and microstructure of the material play an essential role for the formation of a surface layer.

BaGa4O7, a new A3BC10O20 crystalline phase: synthesis, structural determination and luminescence properties

CrystEngComm ◽  
2015 ◽  
Vol 17 (32) ◽  
pp. 6127-6135 ◽  
Author(s):  
Marina Boyer ◽  
Emmanuel Véron ◽  
Ana Isabel Becerro ◽  
Florence Porcher ◽  
Matthew R. Suchomel ◽  
...  
Keyword(s):  
Crystalline Phase ◽  
Luminescence Properties ◽  
Structural Determination ◽  
Phase Synthesis ◽  
Luminescence Emission ◽  
Red Luminescence

A new compound, BaGa4O7, is found by cooling from the melt. Part of the A3BC10O20 family, it exhibits strong orange-red luminescence emission when doped with Eu3+.

Visible luminescence properties of Er3+–Dy3+ codoped tellurite glasses

2010 ◽  
Vol 101 (4) ◽  
pp. 777-780 ◽  
Author(s):  
Feng Zhang ◽  
Zhisong Xiao ◽  
Lu Yan ◽  
Fang Zhu ◽  
Anping Huang
Keyword(s):  
Luminescence Properties ◽  
Tellurite Glasses ◽  
Visible Luminescence

Ultraviolet and visible luminescence properties of Sc3+ doped single crystals

2002 ◽  
Vol 35 (1) ◽  
pp. 1-2 ◽  
Author(s):  
I.S Bykov ◽  
A.B Dubovsky ◽  
L.I Kazakova
Keyword(s):  
Single Crystals ◽  
Luminescence Properties ◽  
Visible Luminescence
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