Microstructure and Optical Properties of ZnS:Mn Nanocrystals

2013 ◽  
Vol 652-654 ◽  
pp. 192-196
Author(s):  
Jin Hua Ma ◽  
Chang Zheng Wang ◽  
Chang Yong Sun
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Hexagonal Phase ◽  
Blue Shift ◽  
Emission Peak ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Strong Emission ◽  
Luminescence Peak ◽  
Structure Morphology

Abstract. By using Na2S•9H2O as source precursor and citric acid as stabilizer, ZnS:Mn nanocrystallines were synthesized by solvothermal method. They were annealed at 800 oC in the charcoal powder. The structure, morphology and optical properties were investigated by using X-ray diffraction spectra (XRD), scanning electron microscopy (SEM), and Spectrofluorophotometer respectively. The results showed that all unannealed ZnS:Mn nanocrystallines were about 3~5 nm of particle size and have cubic structure, and all annealed samples were about 30-70 nm of particle size and have mixed structure of the cubic phase and hexagonal phase. Moreover, Mn2+ took the place of Zn2+ in ZnS:Mn. With the increment of Mn2+ content, there occurred a strong emission peak at about 596nm which can be attributed to the Mn2 + leap from 4T1 to 6A1. In addition, the intensity of 596nm emission peak first increased and then decreased with the increment of Mn2+ content, reaching a maximum at about 15% of Mn2+ content. After annealing Mn2+ emission peak intensity is about 20 times that before annealing, and the luminescence peak also showed slightly blue shift.

Effect of Doping on the Structural and Optical Properties of Microwave-Assisted Synthesis of ZnSe@ZnS Core-Shell Quantum Dots

2009 ◽  
Vol 1207 ◽  
Author(s):  
Sonia J Bailon-Ruiz ◽  
Oscar Perales-Perez ◽  
Surinder P Singh ◽  
Paul M Voyles
Keyword(s):  
Quantum Dots ◽  
Blue Shift ◽  
Host Lattice ◽  
Emission Peak ◽  
Microwave Assisted Synthesis ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Strong Emission ◽  
X Ray ◽  
Doped Quantum Dots

AbstractPure and Cu-doped quantum dots of ZnSe@ZnS were synthesized in aqueous phase using microwave irradiation at 140 °C. X-ray diffraction analyses suggested the development of a ZnSe-ZnS structure. UV-vis measurements evidenced that the presence of Cu species in quantum dots caused the blue shift of exciton peaks with respect to pure, i.e. non doped ones. Photoluminescence spectra of quantum dots synthesized at Zn/Cu mole ratios of 1/0.001 and 1/0.005 exhibited a very strong emission peak centered on ˜ 515 nm. On the contrary, a weak emission peak was observed at 412 nm in pure ZnSe@ZnS quantum dots. The observed emission at 515 nm was attributed to the internal doping of Cu species, which should have induced d-d transitions in the host lattice. Quenching of the luminescence at 515 nm was observed for nominal Cu concentrations above 0.005 mM.

scholarly journals Effect of laser fluence on structural transformations and photoluminescence quenching of Zinc Selenide nanoparticles thin films

2019 ◽  
Vol 29 (4) ◽  
pp. 122
Author(s):  
Nadheer Jassim Mohammed
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Laser Fluence ◽  
Hexagonal Phase ◽  
Blue Shift ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Znse Nanoparticles ◽  
X Ray ◽  
Pl Spectra

Abstract We reported in this work the growth of ZnSe nanoparticles thin films deposited on glass substrates were synthesized by a pulsed laser deposition (PLD) method. The as obtained films were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), UV-VIS Spectrophotometer, and Photoluminescence (PL) spectra. X-ray diffraction study confirmed the transformation the cubic phase of ZnSe nanoparticles into hexagonal phase by increase the laser fluence from (4.77-5.97) J/cm2. The particle size variations were achieved by varying the laser fluence of prepared films. XRD studies and TEM images confirmed the nanometer size was found to lie in the range of 12-80 nm. A UV-VIS study was carried out to measure the band gap of the ZnSe nanoparicles thin films and it showed a blue shift with respect to the bulk value. The PL spectra at room temperature (300K) of the films showed the decrease of maximum values at at 522 nm( 2.379), 521 nm (2.3838) and 520 nm (2.3882 eV) for the laser fluence (4.77, 5.57 and 5.97 J/cm2), respectively. We assigned the variation due a larger number of non-radiative recombination centers appears in the films.

scholarly journals Cubic InGaN Grown by MOCVD

1999 ◽  
Vol 4 (S1) ◽  
pp. 239-243
Author(s):  
J.B. Li ◽  
Hui Yang ◽  
L.X. Zheng ◽  
D.P. Xu ◽  
Y.T. Wang
Keyword(s):  
Room Temperature ◽  
Emission Peak ◽  
Buffer Layers ◽  
Cubic Phase ◽  
Yellow Luminescence ◽  
X Ray Diffraction ◽  
High Quality ◽  
X Ray ◽  
Cubic Gan ◽  
Pl Emission

We report on the growth of high-quality cubic phase InGaN on GaAs by MOCVD. The cubic InGaN layers are grown on cubic GaN buffer layers on GaAs (001) substrates. The surface morphology of the films are mirror-like. The cubic nature of the InGaN films is obtained by X-ray diffraction (XRD) measurements. The InGaN layers show strong photoluminescence (PL) at room temperature. Neither emission peak from wurtzite GaN nor yellow luminescence is observed in our films. The highest In content as determined by XRD is about 17% with an PL emission wavelength of 450 nm. The FWHM of the cubic InGaN PL peak are 153 meV and 216 meV for 427 nm and 450 nm emissions, respectively. It is found that the In compositions determined from XRD are not in agreement with those estimated from PL measurements. The reasons for this disagreement are discussed.

scholarly journals Identification of tetragonal and cubic structures of zirconia using synchrotron x-radiation source

1991 ◽  
Vol 6 (6) ◽  
pp. 1287-1292 ◽  
Author(s):  
Ram Srinivasan ◽  
Robert J. De Angelis ◽  
Gene Ice ◽  
Burtron H. Davis
Keyword(s):  
Particle Size ◽  
Radiation Source ◽  
Sol Gel ◽  
Yttria Stabilized Zirconia ◽  
Tetragonal Structure ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Synchrotron Source ◽  
Three Samples

X-ray diffraction from a synchrotron source was employed in an attempt to identify the crystal structures in zirconia ceramics produced by the sol-gel method. The particles of chemically precipitated zirconia, after calcination below 600 °C, are very fine, and have a diffracting particle size in the range of 7–15 nm. As the tetragonal and cubic structures of zirconia have similar lattice parameters, it is difficult to distinguish between the two. The tetragonal structure can be identified only by the characteristic splittings of the Bragg profiles from the “c” index planes. However, these split Bragg peaks from the tetragonal phase in zirconia overlap with one another due to particle size broadening. In order to distinguish between the tetragonal and cubic structures of zirconia, three samples were studied using synchrotron radiation source. The results indicated that a sample containing 13 mol% yttria-stabilized zirconia possessed the cubic structure with a0 = 0.51420 ± 0.00012 nm. A sample containing 6.5 mol% yttria stabilized zirconia was found to consist of a cubic phase with a0 = 0.51430 ± 0.00008 nm. Finally, a sample which was precipitated from a pH 13.5 solution was observed to have the tetragonal structure with a0 = 0.51441 ± 0.00085 nm and c0 = 0.51902 ± 0.00086.

scholarly journals Synthesis and optical properties of self-assembled flower-like CdS architectures by mixed solvothermal process

2010 ◽  
Vol 8 (5) ◽  
pp. 1027-1033 ◽  
Author(s):  
Junhao Zhang ◽  
Yuhui Wu ◽  
Jia Zhu ◽  
Shaoxing Huang ◽  
Dongjing Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Optical Properties ◽  
X Ray Diffraction ◽  
Wurtzite Phase ◽  
Strong Emission ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Self Assembled ◽  
Xrd Patterns ◽  
Hexagonal Wurtzite Phase

AbstractSelf-assembled CdS architectures with flower-like structures have been synthesized by a mixed solvothermal method using ethylene glycol and oleic acid as the mixed solvent at 160°C for 12 h. The results of X-ray diffraction (XRD) patterns, field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images indicate that the product exists as the hexagonal wurtzite phase and conatins of larger numbers of flower-like CdS architectures with diameters of 1.8–3 μm. The selected-area electron diffraction (SAED) pattern and the high resolution transmission electron microscope (HRTEM) image reveal that the grain has better crystallinity. The optical properties of flower-like CdS architectures were also investigated by ultraviolet-visable (UV-vis) and photoluminescence spectroscopy at room temperature. A strong peak at 490 nm is shown in the UV-vis absorption, while an emission at 486 nm and another strong emission at 712 nm are shown in the PL spectrum.

Synthesis and Optical Properties of Annealed Cr Doped ZnS Nanoparticles

2013 ◽  
Vol 678 ◽  
pp. 163-167 ◽  
Author(s):  
D. Amaranatha Reddy ◽  
G. Murali ◽  
N. Madhusudhana Rao ◽  
R.P. Vijayalakshmi ◽  
B.K. Reddy
Keyword(s):  
Optical Properties ◽  
Hexagonal Phase ◽  
Blue Emission ◽  
Precipitation Method ◽  
Cubic Phase ◽  
Structural And Optical Properties ◽  
Zns Nanoparticles ◽  
Blue Emission Peak ◽  
Co Precipitation ◽  
Surface Morphologies

Undoped and Cr doped ZnS nanoparticles with Cr concentrations of 3.0 at.% were prepared by a chemical co-precipitation method for the fist time, using 2-Mercaptoethanol as the capping agent and annealed the synthesized particles at 600°C for 3h in air. The effect of annealing on morphological, structural and optical properties of ZnS and ZnS:Cr have been studied and compared with as prepared samples. EDAX measurements confirmed the presence of Cr in the ZnS lattice and it also confirms the conversion of ZnS into ZnO after annealed at 600 0C/3h. Surface morphologies of all samples were characterized using scanning electron microscopy (SEM). XRD spectra of as synthesized nanoparticles of ZnS and ZnS:Cr exhibited cubic phase. After annealing, the cubic phase is transformed into hexagonal phase. The particle sizes of the ZnS:Cr powders were increased from 5 to 30 nm when the powders were annealed at 600°C. A stable blue emission peak at 445 nm is observed from the as prepared samples (pure ZnS and Cr doped ZnS) but annealed at 600 0C the PL peaked at 500 nm for pure ZnS and Cr doped ZnS nanoparticles exhibited PL peak at 500 nm as well as 654 nm. The emission intensity decreased in annealed particles compared to as synthesized samples.

Frequency dependence and fuel effect on optical properties of nano TiO2-based structures

2016 ◽  
Vol 30 (18) ◽  
pp. 1650247 ◽  
Author(s):  
Mahdi Ghasemifard ◽  
Misagh Ghamari ◽  
Meysam Iziy
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Average Particle Size ◽  
Combustion Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Nano Tio2 ◽  
Transmission Electron ◽  
Auto Combustion ◽  
Xrd Patterns

TiO2-(Ti[Formula: see text]Si[Formula: see text]O2 nanopowders (TS-NPs) with average particle size around 90 nm were successfully synthesized by controlled auto-combustion method by using citric acid/nitric acid (AC:NA) and urea/metal cation (U:MC). The structure of powders was studied based on their X-ray diffraction (XRD) patterns. The XRD of TS-NPs shows that rutile and anatase are the main phases of TS-NPs for AC:NA and U:MC, respectively. Particle size and histogram of nanopowders were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Optical properties of TS-NPs were calculated by Fourier transform infrared spectroscopy (FTIR) and Kramers–Kroning (KK) relation. Plasma frequencies of TS-NPs obtained from energy loss functions depend on fuels as a result of changes in crystal structure, particle size distribution, and morphology.

scholarly journals SEED MEDIATED SYNTHESIS OF HEXAGONAL S-DOPED ZnO NANOROD AND ITS PHYSICAL PROPERTIES

2021 ◽  
Vol 6 (1) ◽  
pp. 19-24
Author(s):  
Yolanda Rati ◽  
Akrajas Ali Umar ◽  
Yanuar Hamzah ◽  
Ari Sulistyo Rini
Keyword(s):  
Optical Properties ◽  
Zno Nanorod ◽  
X Ray Diffraction ◽  
Optical Absorbance ◽  
Optical Absorption Peak ◽  
Structure Morphology ◽  
Vis Spectroscopy ◽  
Wide Range ◽  
Electron Scanning Microscopy ◽  
Seed Mediated

Sulfur-doped zinc oxide (S-ZnO) nanorod has been successfully synthesized via the seed-mediated hydrothermal method with different sulfur concentrations (0%, 1%, 2.5%). This research aims to study the influence of the concentration of sulfur on the structure, morphology, and optical properties of ZnO as a promising material in a wide range of applications.  Crystal structure, morphology, and optical properties of the samples were characterized using  X-Ray Diffraction (XRD), Field Emission Electron Scanning Microscopy (FESEM), and UV-Vis Spectroscopy, respectively. The XRD pattern shows the strongest peak at 2θ = 34.43° for crystal orientation of (002). The crystallinity properties of the S-ZnO sample are higher compared to the ZnO sample.  The FESEM images of the 1% S-ZnO sample exhibit the highest nanorod density arrangement. The optical absorbance of the higher sulfur dopant possesses a higher optical absorption peak on the UV-Vis spectrum. The results indicate that S doping to ZnO can alter the structural, morphological, and optical properties of ZnO.

Investigation of Nanostructure and Optical Properties of Flexible AZO Thin Films at Different Powers of RF Magnetron Sputtering

NANO ◽  
2018 ◽  
Vol 13 (06) ◽  
pp. 1850062 ◽  
Author(s):  
Sh. Khatami ◽  
L. Fekri Aval ◽  
G. Behzadi Pour
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Magnetron Sputtering ◽  
Rf Magnetron Sputtering ◽  
Rf Power ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
Structure Morphology ◽  
Xrd Patterns ◽  
Predominant Direction

In this study Al-doped Zinc Oxide (AZO) thin films were successfully deposited on the flexible Polymethyl methacrylate (PMMA) substrate by RF magnetron sputtering. The effects of RF power on the crystal structure, morphology, thickness and optical properties of AZO thin films have been investigated. The AZO thin films were analyzed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), DEKTAK 3 profilometer, UV–Visible spectroscopy and room temperature photoluminescence (PL) spectroscopy. The XRD patterns show that increase of RF power leads to increase in the predominant direction along (100) and crystal plane of hexagonal ZnO. Moreover, the transmittance of thin films decreased from 76% to 61% and optical bang gap varied among 3.34[Formula: see text]eV to 3.22[Formula: see text]eV with increasing RF power. The PL spectra show excellent light-emitting characteristics: 375[Formula: see text]nm, 428[Formula: see text]nm, 467[Formula: see text]nm and 505[Formula: see text]nm. The results indicate that the peak intensity increases with increasing RF power from 80[Formula: see text]W to 180[Formula: see text]W.

Structural Investigation of Cubic-Phase InN on GaAs (001) Grown by MBE under In- and N-Rich Growth Conditions

2007 ◽  
Vol 31 ◽  
pp. 215-217 ◽  
Author(s):  
S. Kuntharin ◽  
S. Sanorpim ◽  
T. Nakamura ◽  
R. Katayama ◽  
Kentaro Onabe
Keyword(s):  
Growth Condition ◽  
Structural Modification ◽  
Structural Investigation ◽  
Hexagonal Phase ◽  
Critical Role ◽  
Growth Conditions ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Phase Purity ◽  
X Ray

We have investigated effect of the In- and N-rich growth conditions on the structural modification of cubic-phase InN (c-InN) films grown on GaAs (001) substrates by rf-plasmaassisted molecular beam epitaxy (RF-MBE). High resolution x-ray diffraction (HRXRD) and Raman scattering measurements were performed to examine the hexagonal phase generation in the c-InN grown films. It is evident that higher crystal quality c-InN films with higher cubic phase purity (~82%) were achieved under the In-rich growth condition. On the other hand, for the N-rich growth condition, the c-InN films exhibited higher incorporation of hexagonal phase, which is generated in the cubic phase through the incidental stacking faults on the c-InN (111) planes. Our results demonstrate that the In-rich growth condition plays a critical role in the growth of high quality c-InN films with higher cubic phase purity.

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