TMDC Horizontal Poster
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This document summarizes research into growing single crystals of ternary transition metal dichalcogenide compounds. The researchers are attempting to grow crystals of NbIrTe4 using chemical vapor transport. They analyzed crystals from different growth conditions but found results were inconsistent. Moving forward they will try growth from melt reactions and aim to identify parameters hindering consistency like cleanliness and vacuum/pressure conditions.
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![Ricardo Vidrio1, Ryan Need1, Stephen Wilson1
1 Materials Department, University of California, Santa Barbara, CA, USA
Acknowledgements
The Growth of Two Dimensional Transition Metal Dichalcogenides
Transition metal dichalcogenides
are the semiconducting analog to graphene
Crystal growth reactions are carried out
using the chemical vapor transport mechanism
Mass amounts of powder for NbIrTe4 [in mg]
Element Mass with
excess
tellurium
(1:1:4.3)
Mass without
excess
tellurium
(1:1:4)
Mass with
excess
tellurium
(1:1:8)
niobium (Nb) 111.4 116.8 71.1
iridium (Ir) 230.5 241.6 147
tellurium (Te) 658.0 641.6 782
Pressure = 5x10-5mbar
Growth time = 7 days
Temperature: Temperature gradient, THOT=1000°C and TCOLD=900°C
Powder found in ampoules after reaction
is analyzed using x-ray diffraction
This project was partially supported by the LSAMP program of the National Science
Foundation under Award no. DMR-1102531 and by the MRSEC Program of the National
Science Foundation under Award No. DMR- 1121053. I also acknowledge the
contribution that Ryan Need has placed forward on this project. His mentorship and
patience proved invaluable throughout the entire summer. I also want to thank Prof.
Stephen Wilson for allowing me to research in his lab this summer.
The location, height, and shape of the peaks is analyzed
using a process known as Rietveld refinement.
(a) Tellurium crystals
deposited inside of
ampoule vial via
microscope
(b) SEM micrograph of
tellurium crystals
(c) Electrical
measurement of
tellurium crystals
Electrical and chemical analysis of crystals
revealed them to be pure tellurium
SEM micrographs reveal the hexagonal crystal structure of tellurium. The
ratio of diameter/length was found to be dependent on the pressure
present in the ampoule during growth.
Temperature-dependent electrical transport confirmed that our tellurium
crystals did not behave like semiconductors, but instead like semimetals
as previous literature had reported.
Moving forward, growth-from-the-melt
reactions will be attempted
There is no ternary phase diagram available for
this system so it is possible that NbIrTe4 is a
congruently melting phase that could be grown
straight from a melt of the three elements.
Since tellurium melts first (M.P. is 449°C), it was
placed in the bottom of the ampoule so that
niobium (M.P. is 2,469°C) and iridium (M.P. is
2,447°C) sink into liquid and mix properly.
Need to identify parameters that hinder inconsistency:
(1) Determine if cleanliness is an important factor in hindering
inconsistency
(2) Make sure that we set up a proper vacuum and pressure
conditions inside of ampoule
Image source:
http://www.intech
open.com/source/
html/43029/media
/image1.png
Two-dimensional transition metal
dichalcogenides combine a sheet-like
structure with versatile electrical
properties.
M = transition metal
X = chalcogenide
Specifically, we’re attempting to grow
single crystals of ternary dichalcogenides
compounds.
M = transition metal #1
M’ = transition metal #2
X = chalcogenide
These may allow for increased
functionality through cation chemistry
compared to their binary counterparts.
MX2
MM’X4
Raw x-ray data is collected on a powdered sample. An example data
set is shown below in blue.
After refinement, our model matches the data closely, and quantifies
which phases are present in the powder and in what amounts.
One-third of our reactions have produced
high quantities of our desired phase, NbIrTe4
Using bromine and iodine as transport agents, as well as using no
transport agent, has resulted in batches with >70% NbIrTe4.
However, when repeated, none of our batches have produced
repeatable results.
This leads us to believe there is some un-captured variable in our
experiment up to now.](https://image.slidesharecdn.com/21515045-e3ec-414f-a82d-614f6bfc673f-160430225524/85/TMDC-Horizontal-Poster-1-320.jpg)
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The researchers were attempting to grow high quality single crystals of the ternary dichalcogenide NbIrTe4 using two different growth methods: chemical vapor transport and a reaction using molten tellurium. Preliminary results using chemical vapor transport were inconsistent, yielding powders of various binary phases rather than large NbIrTe4 crystals. Using a reaction with molten tellurium in contact with Nb and Ir powders produced NbIrTe4 crystals at the interface, confirming the layered growth technique is more promising. Moving forward, the researchers will optimize this new technique for growing larger NbIrTe4 crystals and also explore synthesizing the ungrown compound ZrIrTe4.
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This document summarizes an experiment to grow crystals of the ternary transition metal dichalcogenide NbIrTe4 using chemical vapor transport reactions. Initial attempts using this method produced inconsistent and undesired results due to the added complexity of a third element. Subsequent experiments layering niobium and iridium powders above tellurium in an ampoule produced the first mm-sized crystals of NbIrTe4. Moving forward, the authors plan to optimize growth conditions and explore other unstudied transition metal dichalcogenides.
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4. Has an isotropic transition around 67°C but x-ray diffraction found a crystal phase below this temperature with no observable liquid crystal phase.
M.Perez R.Jacobs poster 2015
The document discusses the synthesis and characterization of various photocatalyst materials for wastewater treatment. Particle sizes of TiO2 were prepared by hand grinding and ball milling, with smaller particle sizes from hand grinding showing better photocatalytic activity. Electron-doped TiO2 samples were synthesized via solid-state reactions and characterized using XRD. TaON was attempted through metathesis reactions but resulted mainly in LiTaO3; a subsequent iodine treatment improved the TaON yield. The photocatalytic degradation of methylene blue was evaluated for the materials using a solar simulator, with effects of particle size, doping, and time monitored through spectroscopy.
10.1007_s12633-015-9356-x
This document summarizes research on nanocrystalline titania powders doped with copper. Key findings include:
- Copper doping affected the phase stability of titania, promoting the rutile phase at higher temperatures.
- The 5% copper-doped titania sample had the largest degradation of methylene orange dye under visible light, indicating better photocatalytic activity than pure titania.
- UV-Vis spectroscopy estimated the band gap of the copper-doped titania to be 1.9-2 eV, lower than pure titania and allowing absorption of visible light.
Le3619061915
International Journal of Engineering Research and Applications (IJERA) aims to cover the latest outstanding developments in the field of all Engineering Technologies & science.
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Synthesis, characterization and kinetic studies of nickel (ii)
This document summarizes the synthesis, characterization, and kinetic studies of a nickel(II) complex of dibenzoylmethane and its 1,10-phenanthroline adduct. The compounds were synthesized using nickel(II) acetate and characterized using elemental analysis, magnetic susceptibility, IR and UV-Vis spectroscopy. Elemental analysis showed a 1:2 metal-ligand ratio for both compounds. Kinetic studies revealed the formation of the nickel complex occurs via a second-order reversible reaction between nickel and dibenzoylmethane with a rate constant between 1.7 x 103–9.2 x 103 moldm-3.
Navneeta Katyan_MS thesis (1)
The document summarizes a study on the variation in melting point of encapsulated silver nanoparticles with size. Silver nanoparticles were synthesized with inert oxide shells like ZrO2 and SiO2 using chemical methods. Characterization techniques like XRD, SEM, TEM and EDS were used to analyze the structure and composition. Differential thermal and scanning calorimetry were employed to determine the melting transition at different sizes. Samples with silver core sizes of around 12nm and 30nm were prepared using a ZrO2 shell, while SiO2 shell samples were synthesized by varying reaction parameters to obtain silver cores between 2nm to 30nm.
10.1007_s11082-014-9975-2
This document discusses the effect of heating rate on the structural and optical properties of silicon and magnesium co-doped zirconia nanopowders prepared by a sol-gel method. X-ray diffraction analysis showed that different heating rates between 1-10°C/min affected the formation of tetragonal and cubic phases, crystallinity, and particle size. Ultraviolet-visible spectroscopy showed that the band gap energy of the doped zirconia crystals decreased depending on the heating rate, with a minimum band gap of around 3-3.2 eV.
Growth, structural, optical, electrical and SHG studies of N-N′ allylthiourea...
Potassium Dihydrogen Phosphate (KDP) crystals are one of the most popular crystals used for Non-linear
Optical (NLO) applications. Pure KDP single crystals and KDP crystals doped with N-N′ allylthiourea were
grown by the method of slow evaporation from aqueous solutions. The grown pure and doped crystals were
confirmed by X-ray single crystal and powder diffraction studies. The pure and doped crystals were
characterized by FTIR spectroscopy studies. Absorptions of these grown crystals were analyzed using UV–Vis–
NIR studies, and it was found that these crystals possess minimum absorption in the entire visible region.
Nonlinear optical studies of pure and doped crystals were carried out and it reveals that the dopants have
increased the efficiency of KDP crystals. Dielectric measurements were carried out along both the unique axis
and perpendicular directions at various temperatures ranging from 40 to 150 °C. The dielectric constant and the
dielectric loss values of N-N′ allylthiourea doped KDP crystals were lower than the pure KDP crystals. Also, it
indicates that 0.8 mole% N-N′ allylthiourea addition to KDP leads to low permittivity value dielectrics. The
results are discussed.
A study of lattice parameters and dielectric properties against temperature a...
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Synthesis and characterization of pani ti o2 nanocomposite for solar
This document summarizes the synthesis and characterization of a polyaniline-titanium dioxide (PANI-TiO2) nanocomposite for use in solar cells. PANI-TiO2 nanocomposites with different TiO2 concentrations were prepared and characterized using XRD, FTIR, FESEM, and I-V measurements. XRD and FTIR confirmed the formation of the nanocomposite. FESEM showed uniform distribution of TiO2 nanoparticles in the PANI matrix. I-V characterization demonstrated that conductivity increased with TiO2 concentration up to 6%, making PANI-TiO2 suitable for solar cell applications.
Characterization of different dopants in TiO2 Structure by Pulsed Laser Dep...
Characterization of different dopants in TiO2 Structure by Pulsed Laser Deposition
A thesis submitted By: Khaled Z.Yahya
Supervised by: Prof.Dr. Adawiya J.Haider Prof.Dr. Raad M.S.Al-Haddad
M044086066
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Fq3610331039
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
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Mixed a site cation higher-order ruddlesden-popper phase materials as intermediate-temperature solid oxide fuel cell cathodes-c
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Synthesis, characterization and kinetic studies of nickel (ii)
Synthesis, characterization and kinetic studies of nickel (ii)
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Growth, structural, optical, electrical and SHG studies of N-N′ allylthiourea...
A study of lattice parameters and dielectric properties against temperature a...
A study of lattice parameters and dielectric properties against temperature a...
Synthesis and characterization of pani ti o2 nanocomposite for solar
Synthesis and characterization of pani ti o2 nanocomposite for solar
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Characterization of different dopants in TiO2 Structure by Pulsed Laser Dep...
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This document summarizes Paulo Sergio Fonseca's research project on growing and characterizing monolayer molybdenum disulfide (MoS2) using chemical vapor deposition (CVD). The goals were to grow monolayer MoS2 islands using CVD, characterize the material properties using techniques like photoluminescence spectroscopy and atomic force microscopy, fabricate devices on the MoS2 using electron beam lithography, and investigate the electrical properties through transport measurements. Key accomplishments included the successful growth and characterization of CVD monolayer MoS2, as well as fabricating a device to enable future transport studies of the material's electron mobility.
seawater desalination using MoS2 nanopore POWER POINT
The document discusses the use of single layer molybdenum disulfide (MoS2) nanopores for desalination. It begins with an introduction to MoS2, describing its lamellar structure and weak van der Waals forces between layers. It then discusses using MoS2 nanopores for more efficient and energy-saving desalination compared to traditional reverse osmosis. The document concludes that single layer MoS2 nanopores show promise as an effective membrane for seawater desalination due to their thin, ultrastructure and lower energy requirements.
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Invited lecture of the Simposium N "Surface Engineering - functional coatings and modified surfaces" at the XIII SBPMat (Brazilian MRS) meeting, in João Pessoa (Brazil). The lecture took place on September 29th, 2014.
The speaker was Christopher Muratore, "Wright Brothers Institute Endowed Chair Professor" at the Department of Chemical and Materials Engineering from University of Dayton (USA).MoS2
Rahul Raghvendra's seminar discussed molybdenum disulfide (MoS2), a 2D semiconductor material that can potentially replace silicon. MoS2 has desirable properties such as a tunable bandgap, high mobility, flexibility and transparency. The seminar covered MoS2's atomic structure, electrical properties, fabrication methods and applications in sensors, memory devices and flexible electronics. Challenges include controlling the number of MoS2 monolayers deposited and developing devices compatible with plastic substrates.
Band structure and surface properties of 1-4 layers of MoS2
A brief introduction to 1-4ML MoS2 ARPES study - background, motivation, tools, measurement, results.
PPT thesis defense_nikhil
h-BN has potential as an ideal dielectric material for 2D electronics. As a gate dielectric, h-BN provides improved carrier mobility and resists dielectric breakdown at high electric fields. When used as a substrate, h-BN enhances graphene conductivity and mobility while improving reliability by facilitating better heat dissipation than conventional dielectrics like SiO2. Overall, h-BN shows promise as an ubiquitous dielectric that can fulfill critical roles in 2D heterostructures and devices.
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This document summarizes the synthesis and characterization of a new benzotriazole phthalocyanine nickel(II) complex to be used as a photostabilizer for low density polyethylene. The complex was prepared and characterized using elemental analysis and FT-IR spectroscopy. Experimental investigation showed that this complex acts as an excellent photostabilizer for LDPE, providing stabilization through multiple pathways, unlike commercial antioxidants which typically offer only single mechanisms of protection. Testing revealed that the complex performed better than LDPE samples containing other common antioxidants at preventing degradation when exposed to UV light over time. Therefore, the complex is a promising new photostabilizer for improving the UV resistance of LDPE.
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The document summarizes research on synthesizing and characterizing 3 mol% yttria stabilized tetragonal zirconia polycrystals (3Y-TZP) nanopowders using a simple co-precipitation process. Thermogravimetric analysis showed weight losses associated with dehydration of the freeze-dried precursor powders up to 1020 K. Differential scanning calorimetry identified exothermic peaks corresponding to atomic rearrangement and crystallization of tetragonal ZrO2 at 523 K and 753 K, respectively. X-ray diffraction analysis revealed the freeze-dried powders remained amorphous until calcined at 773 K, at which point they crystallized
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This document summarizes research on the synthesis and characterization of cadmium-substituted nickel ferrite (Ni1-xCdxFe2O4) powders prepared using an auto-combustion technique. X-ray diffraction analysis confirmed the formation of single-phase spinel structures for all compositions sintered at 1050°C. Lattice parameters increased linearly with increasing cadmium content due to the larger ionic radius of Cd2+. Bulk density decreased with higher cadmium concentration but increased with sintering temperature. FTIR analysis showed that absorption band positions shifted to lower wave numbers with cadmium substitution due to redistribution of Fe3+ ions between octahedral and tetrahedral sites.
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The document summarizes research on the synthesis of lead tungstate (PbWO4) hollow nanostructures via a low-temperature hydrothermal method at different pH levels without using surfactants. PbWO4 samples were characterized using XRD, TEM, and photoluminescence. XRD showed the samples were highly crystalline and single phase. TEM images revealed the formation of hollow nanoparticles and nanotubes at pH 7. The nanotubes had an outer diameter of 12.37 nm and lengths from 80-170 nm. Photoluminescence spectroscopy exhibited a broad blue-green emission that was fitted with four Gaussian peaks attributed to excited states of emission centers.
Heterogeneous Catalysis - Opportunities and Challenges
This document discusses opportunities and challenges in heterogeneous catalysis. The key challenges are meeting societal needs and developing a basic scientific understanding. Opportunities include designing catalysts at the nano-scale, rational catalyst design based on scientific insights, and accelerated discovery through large data-driven methods. Rational catalyst design requires understanding what determines catalytic properties and how to influence them. Basic understanding from computational and experimental studies is providing insights to guide catalyst optimization.
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STRUCTURAL AND DIELECTRIC STUDIES OF TERBIUM SUBSTITUTED NICKEL FERRITE NANOP...
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TMDC Horizontal Poster
- 1. Ricardo Vidrio1, Ryan Need1, Stephen Wilson1 1 Materials Department, University of California, Santa Barbara, CA, USA Acknowledgements The Growth of Two Dimensional Transition Metal Dichalcogenides Transition metal dichalcogenides are the semiconducting analog to graphene Crystal growth reactions are carried out using the chemical vapor transport mechanism Mass amounts of powder for NbIrTe4 [in mg] Element Mass with excess tellurium (1:1:4.3) Mass without excess tellurium (1:1:4) Mass with excess tellurium (1:1:8) niobium (Nb) 111.4 116.8 71.1 iridium (Ir) 230.5 241.6 147 tellurium (Te) 658.0 641.6 782 Pressure = 5x10-5mbar Growth time = 7 days Temperature: Temperature gradient, THOT=1000°C and TCOLD=900°C Powder found in ampoules after reaction is analyzed using x-ray diffraction This project was partially supported by the LSAMP program of the National Science Foundation under Award no. DMR-1102531 and by the MRSEC Program of the National Science Foundation under Award No. DMR- 1121053. I also acknowledge the contribution that Ryan Need has placed forward on this project. His mentorship and patience proved invaluable throughout the entire summer. I also want to thank Prof. Stephen Wilson for allowing me to research in his lab this summer. The location, height, and shape of the peaks is analyzed using a process known as Rietveld refinement. (a) Tellurium crystals deposited inside of ampoule vial via microscope (b) SEM micrograph of tellurium crystals (c) Electrical measurement of tellurium crystals Electrical and chemical analysis of crystals revealed them to be pure tellurium SEM micrographs reveal the hexagonal crystal structure of tellurium. The ratio of diameter/length was found to be dependent on the pressure present in the ampoule during growth. Temperature-dependent electrical transport confirmed that our tellurium crystals did not behave like semiconductors, but instead like semimetals as previous literature had reported. Moving forward, growth-from-the-melt reactions will be attempted There is no ternary phase diagram available for this system so it is possible that NbIrTe4 is a congruently melting phase that could be grown straight from a melt of the three elements. Since tellurium melts first (M.P. is 449°C), it was placed in the bottom of the ampoule so that niobium (M.P. is 2,469°C) and iridium (M.P. is 2,447°C) sink into liquid and mix properly. Need to identify parameters that hinder inconsistency: (1) Determine if cleanliness is an important factor in hindering inconsistency (2) Make sure that we set up a proper vacuum and pressure conditions inside of ampoule Image source: http://www.intech open.com/source/ html/43029/media /image1.png Two-dimensional transition metal dichalcogenides combine a sheet-like structure with versatile electrical properties. M = transition metal X = chalcogenide Specifically, we’re attempting to grow single crystals of ternary dichalcogenides compounds. M = transition metal #1 M’ = transition metal #2 X = chalcogenide These may allow for increased functionality through cation chemistry compared to their binary counterparts. MX2 MM’X4 Raw x-ray data is collected on a powdered sample. An example data set is shown below in blue. After refinement, our model matches the data closely, and quantifies which phases are present in the powder and in what amounts. One-third of our reactions have produced high quantities of our desired phase, NbIrTe4 Using bromine and iodine as transport agents, as well as using no transport agent, has resulted in batches with >70% NbIrTe4. However, when repeated, none of our batches have produced repeatable results. This leads us to believe there is some un-captured variable in our experiment up to now.