Photoluminescence and Raman Spectra of Flux Processed Bulk Single Crystal GaN

2001 ◽  
Vol 680 ◽  
Author(s):  
Chae Ryong Cho ◽  
Sang Eon Park ◽  
Yong Chan Cho ◽  
Se-Young Jeong
Keyword(s):  
Single Crystal ◽  
Photoelectron Spectroscopy ◽  
High Energy ◽  
Bulk Single Crystal ◽  
X Ray Diffraction ◽  
Phonon Modes ◽  
X Ray ◽  
Growth Method ◽  
Bulk Single Crystals ◽  
Gan Crystal

ABSTRACTBulk wurtzite-GaN crystal was obtained with a size more than 3 mm along the length of the crystal and with a thickness 200 ∼ 300 µm at around 750°C and 100 bar for 24 hrs in the flux growth method. The structural and compositional property of the GaN bulk single crystal was also studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. Photoluminescence, cathodoluminescence and micro-Raman measurements at room temperature are investigated for bulk single crystals of wurtzite GaN. The cathodoluminescence peak of near band-to-band transition at 365.5 nm and the E2(high energy, 568 cm−1) and A1(LO, 737 cm−1) Raman phonon modes were obtained according to the different position of the (0001) surface of GaN grown by flux method. Sharp line shape for the strain-sensitive E2 (high) mode is considered to be due to the high crystalline quality of the crystal.

scholarly journals Growth of sillenite Bi12FeO20 single crystals: structural, thermal, optical, photocatalytic features and first principle calculations

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Durga Sankar Vavilapalli ◽  
Ambrose A. Melvin ◽  
F. Bellarmine ◽  
Ramanjaneyulu Mannam ◽  
Srihari Velaga ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Diffraction Method ◽  
Lattice Parameter ◽  
First Principle ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Principle Calculations ◽  
Photodegradation Efficiency

AbstractIdeal sillenite type Bi12FeO20 (BFO) micron sized single crystals have been successfully grown via inexpensive hydrothermal method. The refined single crystal X-ray diffraction data reveals cubic Bi12FeO20 structure with single crystal parameters. Occurrence of rare Fe4+ state is identified via X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The lattice parameter (a) and corresponding molar volume (Vm) of Bi12FeO20 have been measured in the temperature range of 30–700 °C by the X-ray diffraction method. The thermal expansion coefficient (α) 3.93 × 10–5 K−1 was calculated from the measured values of the parameters. Electronic structure and density of states are investigated by first principle calculations. Photoelectrochemical measurements on single crystals with bandgap of 2 eV reveal significant photo response. The photoactivity of as grown crystals were further investigated by degrading organic effluents such as Methylene blue (MB) and Congo red (CR) under natural sunlight. BFO showed photodegradation efficiency about 74.23% and 32.10% for degrading MB and CR respectively. Interesting morphology and microstructure of pointed spearhead like BFO crystals provide a new insight in designing and synthesizing multifunctional single crystals.

Synthesis, Structure and Magnetism of ErCoIn5

2004 ◽  
Vol 848 ◽  
Author(s):  
Evan Lyle Thomas ◽  
Erin E. Erickson ◽  
Monica Moldovan ◽  
David P. Young ◽  
Julia Y. Chan
Keyword(s):  
Magnetic Properties ◽  
Electrical Resistivity ◽  
Magnetic Susceptibility ◽  
Single Crystal ◽  
Experimental Results ◽  
Flux Growth ◽  
X Ray Diffraction ◽  
Metallic Behavior ◽  
X Ray ◽  
Growth Method

AbstractA new member of the LnMIn5 family, ErCoIn5, has been synthesized by a flux-growth method. The structure of ErCoIn5 was determined by single crystal X-ray diffraction. It crystallizes in the tetragonal space group P4/mmm, Z = 1, with lattice parameters a = 4.5400(4) and c = 7.3970(7) Å, and V = 152.46(2) Å3. Electrical resistivity data show metallic behavior. Magnetic susceptibility measurements show this compound to be antiferromagnetic with TN = 5.1 K. We compare these experimental results with those of LaCoIn5 in an effort to better understand the effect of the structural trends observed on the transport and magnetic properties.

Characterization of X-ray irradiated graphene oxide coatings using X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy

2013 ◽  
Vol 28 (2) ◽  
pp. 68-71 ◽  
Author(s):  
Thomas N. Blanton ◽  
Debasis Majumdar
Keyword(s):  
Atomic Force Microscopy ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
High Energy ◽  
X Ray Diffraction ◽  
Carbon Phase ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After

In an effort to study an alternative approach to make graphene from graphene oxide (GO), exposure of GO to high-energy X-ray radiation has been performed. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) have been used to characterize GO before and after irradiation. Results indicate that GO exposed to high-energy radiation is converted to an amorphous carbon phase that is conductive.

Single-crystal X-ray diffraction, EMPA, FTIR and X-ray photoelectron spectroscopy study of narsarsukite from Murun Massif, Russia

2017 ◽  
Vol 81 (2) ◽  
pp. 339-354 ◽  
Author(s):  
E. Schingaro ◽  
E. Mesto ◽  
M. Lacalamita ◽  
F. Scordari ◽  
E. Kaneva ◽  
...  
Keyword(s):  
Single Crystal ◽  
Photoelectron Spectroscopy ◽  
Chemical Study ◽  
Structural Disorder ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Alkaline Massif

AbstractA crystal chemical study of narsarsukite from the Murun alkaline massif, Russia has been carried out combining single-crystal X-ray diffraction, electron microprobe analyses, micro-Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The narsarsukite single crystals are tetragonal (space group I4/m) with unit-cell parameters: 10.7140(1) ≤ a ≤ 10.7183(2) Å and 7.9478(1) ≤ c ≤ 7.9511(1) Å. The XPS analysis showed that Fe occurs in the mineral as Fe3+, whereas the FTIR spectrum showed that the sample studied is anhydrous. The average crystal chemical formula of the Murun narsarsukite is: Na2.04K0.01(V0.015+Ti0.74Zr0.01Al0.01Fe0.223+Mg0.01)1.00Si4.00(O10.74F0.23OH0.03)11.00. Structural disorder at octahedral and interstitial sites was modelled and also discussed in consideration of the main substitutional mechanism Ti4+ + O2– ↔ Fe3+ + (F–, OH–) active in the structure of the mineral.

Characterization of an Yb:LuVO4 single crystal using X-ray topography, high-resolution X-ray diffraction, and X-ray photoelectron spectroscopy

2011 ◽  
Vol 80 (10) ◽  
pp. 1001-1007 ◽  
Author(s):  
W. Paszkowicz ◽  
P. Romanowski ◽  
J. Bąk-Misiuk ◽  
W. Wierzchowski ◽  
K. Wieteska ◽  
...  
Keyword(s):  
High Resolution ◽  
Single Crystal ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Electronic and vibrational decoupling in chemically exfoliated bilayer 2D-V2O5

2021 ◽  
Author(s):  
Reshma P R ◽  
Anees Pazhedath ◽  
Ganesan Karuppiah ◽  
Arun Prasad ◽  
Sandip Dhara
Keyword(s):  
Transition Metal ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Blue Shift ◽  
X Ray Diffraction ◽  
Phonon Modes ◽  
Visible Absorption ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force

Abstract Recently emerged transition metal oxide (TMO) based 2D nanostructures are gaining a foothold in advanced applications. Unlike, 2D transition metal dichalchogenides, it is strenuous to obtain high quality thin TMOs due to exotic surface reconstruction during synthesis. Herein, we report the synthesis of bilayer thin 2D-V2O5 nanosheets using chemical exfoliation. Synchrotron X-ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy substantiate the successful formation of bilayer thin 2D-V2O5. Ultraviolet-visible absorption spectra exhibit a thickness dependent blue shift in the optical band gap, signifying the emergence of electronic decoupling. Raman spectroscopy fingerprinting shows a thickness dependent vibrational decoupling of phonon modes. Further, it has been verified by computing the lattice vibrational modes using density functional perturbation theory. In this study, the manifestation of the electronic and vibrational decoupling is used as a novel probe to confirm the successful exfoliation of bilayer 2D-V2O5 from its bulk counterpart.

Epitaxial growth and magnetic behavior of NiFe2O4 thin films

1996 ◽  
Vol 11 (5) ◽  
pp. 1187-1198 ◽  
Author(s):  
S. Venzke ◽  
R. B. van Dover ◽  
Julia M. Phillips ◽  
E. M. Gyorgy ◽  
T. Siegrist ◽  
...  
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Structural Changes ◽  
Amorphous Material ◽  
Magnetic Behavior ◽  
Bulk Single Crystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ion Channeling ◽  
Transmission Electron

Thin films of NiFe2O4 were deposited on SrTiO3 (001) and Y0.15Zr0.85O2 (yttria-stabilized zirconia) (001) and (011) substrates by 90°-off-axis sputtering. Ion channeling, x-ray diffraction, and transmission electron microscopy studies reveal that films grown at 600 °C consist of ∼300 Å diameter grains separated by thin regions of highly defective or amorphous material. The development of this microstructure is attributed to the presence of rotated or displaced crystallographic domains and is comparable to that observed in other materials grown on mismatched substrates (e.g., GaAs/Si or Ba2YCu3O7/MgO). Postdeposition annealing at 1000 °C yields films that are essentially single crystal. The magnetic properties of the films are strongly affected by the structural changes; unannealed films are not magnetically saturated even in an applied field of 55 kOe, while the annealed films have properties comparable to those of bulk, single crystal NiFe2O4. Homoepitaxial films grown at 400 °C also are essentially single crystal.

3D high-energy-density and low sensitivity materials: synthesis, structure and physicochemical properties of an azide–Cu(ii) complex with 3,5-dinitrobenzoic acid

RSC Advances ◽  
2014 ◽  
Vol 4 (31) ◽  
pp. 16087-16093 ◽  
Author(s):  
Xiangyu Liu ◽  
Qi Yang ◽  
Zhiyong Su ◽  
Sanping Chen ◽  
Gang Xie ◽  
...  
Keyword(s):  
Energy Density ◽  
Coordination Polymer ◽  
Physicochemical Properties ◽  
Single Crystal ◽  
High Energy ◽  
High Energy Density ◽  
X Ray Diffraction ◽  
Materials Synthesis ◽  
X Ray ◽  
Low Sensitivity

A novel 3D energetic coordination polymer of azide–Cu(ii), Cu(3,5-DNBA)(N3), was synthesized and structurally characterized by single crystal X-ray diffraction, where 3,5-DNBA represents 3,5-dinitrobenzoic acid.

A novel 3D energetic MOF of high energy content: synthesis and superior explosive performance of a Pb(ii) compound with 5,5′-bistetrazole-1,1′-diolate

2016 ◽  
Vol 45 (35) ◽  
pp. 13881-13887 ◽  
Author(s):  
Yu Shang ◽  
Bo Jin ◽  
Rufang Peng ◽  
Qiangqiang Liu ◽  
Bisheng Tan ◽  
...  
Keyword(s):  
Single Crystal ◽  
Energy Content ◽  
Metal Organic Framework ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Explosive Performance ◽  
Metal Organic ◽  
Organic Framework

A novel 3D energetic metal–organic framework (MOF) of exceptionally high energy content, [Pb(BTO)(H2O)]n, was synthesized and structurally characterized by single crystal X-ray diffraction.

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