Visible Light Emission from Silicon Nanoparticles

1991 ◽  
Vol 256 ◽  
Author(s):  
D. Zhang ◽  
R. M. Kolbas ◽  
P. Mehta ◽  
A. K. Singh ◽  
D. J. Lichtenwalner ◽  
...  
Keyword(s):  
Silicon Nanoparticles ◽  
Microwave Plasma ◽  
Light Emission ◽  
Crystalline Silicon ◽  
Red Light ◽  
Emission Spectra ◽  
X Ray Diffraction ◽  
Phase Synthesis ◽  
Transmission Electron ◽  
First Time

ABSTRACTOrange-red light emission has been observed for the first time from crystalline silicon nanoparticles produced by gas phase synthesis in a non-thermal microwave plasma. The size and crystalline nature of the particles have been confirmed by transmission electron microscopy and X-ray diffraction. Photoluminescence at 300 K and 77 K has been measured and analyzed. The emission spectra are consistent with quantum mechanical calculations based on a quantum box.

Photoluminescence Quantum Yields from Crystalline and Amorphous Silicon Nanoparticles

2007 ◽  
Vol 1056 ◽  
Author(s):  
Rebecca Anthony ◽  
Uwe Kortshagen
Keyword(s):  
Silicon Nanoparticles ◽  
Crystalline Silicon ◽  
Plasma Reactor ◽  
Quantum Yields ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Non Thermal Plasma ◽  
Amorphous Nanoparticles ◽  
Amorphous Silicon Nanoparticles

ABSTRACTThe optical properties of amorphous and crystalline silicon nanoparticles are studied. By tuning the power of the non-thermal plasma reactor, the structure of the particles is adjusted from amorphous to crystalline nanoparticles. The microstructure is studied using transmission electron microscopy, X-ray diffraction, and Raman vibrational spectroscopy. The photoluminescence quantum yields of crystalline nanoparticle samples are consistently higher than those of amorphous nanoparticles.

scholarly journals Quartz Crystallite Size and Moganite Content as Indicators of the Mineralogical Maturity of the Carboniferous Chert: The Case of Cherts from Eastern Asturias (Spain)

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 611
Author(s):  
Celia Marcos ◽  
María de Uribe-Zorita ◽  
Pedro Álvarez-Lloret ◽  
Alaa Adawy ◽  
Patricia Fernández ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystallite Size ◽  
Archaeological Sites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared And Raman Spectroscopy ◽  
First Time ◽  
Geological Formations

Chert samples from different coastal and inland outcrops in the Eastern Asturias (Spain) were mineralogically investigated for the first time for archaeological purposes. X-ray diffraction, X-ray fluorescence, transmission electron microscopy, infrared and Raman spectroscopy and total organic carbon techniques were used. The low content of moganite, since its detection by X-ray diffraction is practically imperceptible, and the crystallite size (over 1000 Å) of the quartz in these cherts would be indicative of its maturity and could potentially be used for dating chert-tools recovered from archaeological sites. Also, this information can constitute essential data to differentiate the cherts and compare them with those used in archaeological tools. However, neither composition nor crystallite size would allow distinguishing between coastal and inland chert outcrops belonging to the same geological formations.

scholarly journals The Effect of Surfactant-Modified Montmorillonite on the Cross-Linking Efficiency of Polysiloxanes

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2623
Author(s):  
Monika Wójcik-Bania ◽  
Jakub Matusik
Keyword(s):  
Total Pore Volume ◽  
Cross Linking ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Cross ◽  
Chain Lengths ◽  
First Time ◽  
Substituent Influence ◽  
Benzyl Substituent

Polymer–clay mineral composites are an important class of materials with various applications in the industry. Despite interesting properties of polysiloxanes, such matrices were rarely used in combination with clay minerals. Thus, for the first time, a systematic study was designed to investigate the cross-linking efficiency of polysiloxane networks in the presence of 2 wt % of organo-montmorillonite. Montmorillonite (Mt) was intercalated with six quaternary ammonium salts of the cation structure [(CH3)2R’NR]+, where R = C12, C14, C16, and R’ = methyl or benzyl substituent. The intercalation efficiency was examined by X-ray diffraction, CHN elemental analysis, and Fourier transform infrared (FTIR) spectroscopy. Textural studies have shown that the application of freezing in liquid nitrogen and freeze-drying after the intercalation increases the specific surface area and the total pore volume of organo-Mt. The polymer matrix was a poly(methylhydrosiloxane) cross-linked with two linear vinylsiloxanes of different siloxane chain lengths between end functional groups. X-ray diffraction and transmission electron microscopy studies have shown that the increase in d-spacing of organo-Mt and the benzyl substituent influence the degree of nanofillers’ exfoliation in the nanocomposites. The increase in the degree of organo-Mt exfoliation reduces the efficiency of hydrosilylation reaction monitored by FTIR. This was due to physical hindrance induced by exfoliated Mt particles.

Mesoscopic characterization of the optical property of antiphase boundaries in CuPt-ordered GaInP2

1999 ◽  
Vol 588 ◽  
Author(s):  
Y. Ohno ◽  
S. Takeda
Keyword(s):  
Optical Property ◽  
Light Emission ◽  
Polarized Light ◽  
Structural Data ◽  
Luminescence Spectra ◽  
Antiphase Boundaries ◽  
Transmission Electron ◽  
Tem Method ◽  
Low Dimensional ◽  
First Time

AbstractWe have developed an apparatus for polarized cathodoluminescence (CL) spectroscopy combined with transmission electron microscopy (TEM), that enables us to obtain simultaneously structural data in higher spatial resolution by TEM and polarized luminescence spectra by CL of the same microscopic area. The polarized-CL/TEM method is very useful to study the optical properties of low-dimensional microstructures in semiconducting materials. We have applied the method to examine the optical property of antiphase boundaries in CuPt-ordered GaInP2 and found, for the first time, the polarized light emission from the APBs whose habit planes are parallel to the (T11) and (1T0) atomic planes.

Preparation and Characterization of γ-Fe2O3-ZnFe2O4 Composite Nanoparticles

2013 ◽  
Vol 873 ◽  
pp. 152-157
Author(s):  
Long Long Chen ◽  
Jun Ming Li ◽  
Xiao Min Gong ◽  
Jian Li
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Species ◽  
Composite Nanoparticles ◽  
X Ray Diffraction ◽  
Ferrite Core ◽  
Phase Synthesis ◽  
X Ray ◽  
Transmission Electron ◽  
Chemically Induced

Using a chemically induced transition in an FeCl2 solution, γ-Fe2O3 nanoparticles can be prepared from an amorphous precursor composed of FeOOH and Mg (OH)2. Surface modification by adding ZnCl2 during liquid-phase synthesis was attempted. The magnetization, morphology, crystal structure, and chemical species of as-prepared samples were characterized by vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray energy-dispersive spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). The experimental results showed that the surface of the γ-Fe2O3 nanoparticles can be modified by adding ZnCl2 to form composite nanoparticles with a γ-Fe2O3/ZnFe2O4 ferrite core coated with Zn (OH)2 and absorbed FeCl36H2O; this modification can be enhanced by additional NaOH.

Boron Nitride Nanotubes: Nanoparticles Functionalization and Junction Fabrication

2007 ◽  
Vol 7 (2) ◽  
pp. 530-534 ◽  
Author(s):  
Chunyi Zhi ◽  
Yoshio Bando ◽  
Guozhen Shen ◽  
Chengchun Tang ◽  
Dmitri Golberg
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Boron Nitride ◽  
Boron Nitride Nanotubes ◽  
X Ray Diffraction ◽  
Carbon Nanostructure ◽  
Wet Chemistry ◽  
X Ray ◽  
Transmission Electron ◽  
First Time

Adopting a wet chemistry method, Au and Fe3O4 nanoparticles were functionalized on boron nitride nanotubes (BNNTs) successfully for the first time. X-ray diffraction pattern and transmission electron microscopy were used to characterize the resultant products. Subsequently, a method was proposed to fabricate heterojunction structures based on the particle-functionalized BNNTs. As a demonstration, BNNT-carbon nanostructure, BNNT-ZnO and BNNT-Ga2O3 junctions were successfully fabricated using the functionalized particles as catalysts.

scholarly journals Formation of ZnO/Zn0.5Cd0.5Se Alloy Quantum Dots in the Presence of High Oleylamine Contents

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 999
Author(s):  
Yi-An Chen ◽  
Kuo-Hsien Chou ◽  
Yi-Yang Kuo ◽  
Cheng-Ye Wu ◽  
Po-Wen Hsiao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Particle Size ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Average Size ◽  
Alloy Quantum Dots ◽  
First Time

To the best of our knowledge, this report presents, for the first time, the schematic of the possible chemical reaction for a one-pot synthesis of Zn0.5Cd0.5Se alloy quantum dots (QDs) in the presence of low/high oleylamine (OLA) contents. For high OLA contents, high-resolution transmission electron microscopy (HRTEM) results showed that the average size of Zn0.5Cd0.5Se increases significantly from 4 to 9 nm with an increasing OLA content from 4 to 10 mL. First, [Zn(OAc)2]–OLA complex can be formed by a reaction between Zn(OAc)2 and OLA. Then, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) data confirmed that ZnO is formed by thermal decomposition of the [Zn(OAc)2]–OLA complex. The results indicated that ZnO grew on the Zn0.5Cd0.5Se surface, thus increasing the particle size. For low OLA contents, HRTEM images were used to estimate the average sizes of the Zn0.5Cd0.5Se alloy QDs, which were approximately 8, 6, and 4 nm with OLA loadings of 0, 2, and 4 mL, respectively. We found that Zn(OAc)2 and OLA could form a [Zn(OAc)2]–OLA complex, which inhibited the growth of the Zn0.5Cd0.5Se alloy QDs, due to the decreasing reaction between Zn(oleic acid)2 and Se2−, which led to a decrease in particle size.

Direct Synthesis of Silicon Nanowires using Silane and Molten Gallium

2002 ◽  
Vol 737 ◽  
Author(s):  
Shashank Sharma ◽  
Mahendra K. Sunkara ◽  
Elizabeth C. Dickey
Keyword(s):  
Silicon Nanowires ◽  
Crystalline Silicon ◽  
Direct Synthesis ◽  
Growth Direction ◽  
Single Crystalline ◽  
Gas Phase Chemistry ◽  
Transmission Electron ◽  
Phase Chemistry ◽  
First Time ◽  
Low Solubility

ABSTRACTWe report for the first time, bulk synthesis of single crystalline silicon nanowires using molten gallium pools and an activated vapor phase containing silane. The resulting silicon nanowires were single crystalline with <100> growth direction. Nanowires contained an unexpectedly thin, non-uniform oxide sheath determined using high-resolution Transmission Electron Microscopy (TEM). Nanowires were tens of nanometers in diameter and tens to hundreds of microns long. The use of activated gas phase chemistry containing solute of interest over molten metal pools of low-solubility eutectics such as gallium offer a viable route to generate nanowire systems containing abrupt compositional hetero-interfaces.

scholarly journals Synthesis of Novel YbxSb2 − xTe3Hexagonal Nanoplates: Investigation of Their Physical, Structural, and Photocatalytic Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Younes Hanifehpour ◽  
Sang Woo Joo
Keyword(s):  
Electron Microscopy ◽  
Emission Spectra ◽  
Hydrothermal Condition ◽  
X Ray Diffraction ◽  
Dopant Content ◽  
Transmission Electron ◽  
Intensity Changes ◽  
Diffraction Patterns ◽  
Green Solution ◽  
Microscopy Images

Yb-doped Sb2Te3nanomaterials were synthesized by a coreduction method in hydrothermal condition. Powder X-ray diffraction patterns indicate that theYbxSb2−xTe3crystals (x=0.00–0.05) are isostructural with Sb2Te3. The cell parameteradecreases forYbxSb2−xTe3compounds upon increasing the dopant content (x), whilecincreases. Scanning electron microscopy and transmission electron microscopy images show that doping of Yb3+ions in the lattice of Sb2Te3produces different morphology. The electrical conductivity of Yb-doped Sb2Te3is higher than the pure Sb2Te3and increases with temperature. By increasing concentration of the Yb3+ions, the absorption spectrum of Sb2Te3shows red shifts and some intensity changes. In addition to the characteristic red emission peaks of Sb2Te3, emission spectra of doped materials show other emission bands originating fromf-ftransitions of the Yb3+ions. The photocatalytic performance of as-synthesized nanoparticles was investigated towards the decolorization of Malachite Green solution under visible light irradiation.

Synthesis and Properties of SnO2 One-Dimensional Nanomaterials on Pt-Coated Substrates

2006 ◽  
Vol 517 ◽  
pp. 21-24
Author(s):  
Hyoun Woo Kim ◽  
S.H. Shim
Keyword(s):  
Electron Microscopy ◽  
Thermal Evaporation ◽  
Light Emission ◽  
Growth Mechanisms ◽  
X Ray Diffraction ◽  
Rutile Structure ◽  
One Dimensional ◽  
X Ray ◽  
Transmission Electron ◽  
Tetragonal Rutile Structure

We have synthesized the belt-like structures of tin oxide (SnO2) by carrying out the thermal evaporation of solid Sn powders. We have analyzed the samples with scanning electron microscopy, X-ray diffraction, transmission electron microscopy and photoluminescence (PL). The obtained nanobelts were single crystalline with a tetragonal rutile structure. PL spectrum exhibited the visible light emission. We have discussed the possible growth mechanisms.

Sign in / Sign up

Export Citation Format

Share Document