scholarly journals Mechanochemical conversion kinetics of red to black phosphorus and scaling parameters for high volume synthesis

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Samuel V. Pedersen ◽  
Florent Muramutsa ◽  
Joshua D. Wood ◽  
Chad Husko ◽  
David Estrada ◽  
...  
Keyword(s):  
Large Scale ◽  
Near Infrared ◽  
Kinematic Model ◽  
High Volume ◽  
Optoelectronic Device ◽  
High Energy ◽  
Milling Process ◽  
Black Phosphorus ◽  
Ex Situ ◽  
Kinetics Of

Abstract Adopting black phosphorus (BP) as a material in electronic and optoelectronic device manufacturing requires the development and understanding of a large-scale synthesis technique. To that end, high-energy planetary ball milling is demonstrated as a scalable synthesis route, and the mechanisms and conversion kinetics of the BP phase transformation are investigated. During the milling process, media collisions rapidly compress amorphous red phosphorus (RP) into crystalline, orthorhombic BP flakes, resulting in a conversion yield of ≈90% for ≈5 g of bulk BP powder. Milling conversion kinetics, monitored via ex situ x-ray diffraction, manifest a sigmoidal behavior best described by the Avrami rate model with each impact of sufficient energy (>25 mJ) producing BP nuclei; the process appears to be limited by grain growth. Using a kinematic model for ball trajectories and impact energies, the optimum milling condition is determined to be an impact energy near ≈25 mJ and a milling dose near ≈100 kJ/gram. Photoexcitation of exfoliated BP flakes reveals emission in the near-infrared, indicating the formation of few-layer BP, a promising advance for optoelectronic device applications.

Evaluation of Tribological Properties of Organoclay Reinforced UHMWPE Nanocomposites

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Abdul Samad Mohammed ◽  
Annas bin Ali ◽  
Merah Nesar
Keyword(s):  
Tribological Properties ◽  
Large Scale ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
High Energy ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Uniform Dispersion ◽  
Ultrahigh Molecular Weight ◽  
Energy Ball

The current study is aimed to investigate the tribological properties of ultrahigh molecular weight polyethylene (UHMWPE) reinforced with organoclay Cloisite (C15A). Nanocomposites are prepared using a high energy ball milling process followed by hot pressing. Three different loadings of 0.5 wt.%, 1.5 wt.%, and 3 wt.% of C15A, respectively, are used as reinforcement. Results from the ball-on-disk wear tests showed that nanocomposites reinforced with 1.5 wt.% of C15A exhibited best wear resistance and lower coefficient of friction (COF), with C15A reducing the wear rate by 41% and the COF by 38%, when compared to the pristine UHMWPE. These improvements are attributed to the uniform dispersion of the nanosized clay platelets preventing large-scale material removal and formation of a thin tenacious, continuous transfer film on the counterface for C15A organoclay composites. X-ray diffraction (XRD), scanning electron microscopy (SEM), and optical profilometry are used to characterize the morphology of the nanocomposites and the wear tracks. SEM images of worn surfaces indicated more abrasive wear for the case of pristine UHMWPE as compared to organoclay composites.

Constructing stable covalent bonding in black phosphorus/reduced graphene oxide for lithium ion battery anodes

2020 ◽  
Vol 56 (78) ◽  
pp. 11613-11616 ◽  
Author(s):  
Yang Shi ◽  
Zhibin Yi ◽  
Yanping Kuang ◽  
Hanyu Guo ◽  
Yingzhi Li ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Lithium Ion ◽  
High Energy ◽  
Covalent Bonding ◽  
Milling Process ◽  
Black Phosphorus ◽  
Reduced Graphene ◽  
Energy Ball

The long-standing issue of large volume expansion of black phosphorus (BP) was solved by the formation of P–C and P–O–C covalent bands in the BP@in situ reduced graphene oxide nanocomposite through a facile high energy ball-milling process.

scholarly journals Development and Characterization of Mg-SiC Nanocomposite Powders Synthesized by Mechanical Milling

2017 ◽  
Vol 742 ◽  
pp. 165-172 ◽  
Author(s):  
Daniela Penther ◽  
Claudia Fleck ◽  
Alireza Ghasemi ◽  
Ralf Riedel ◽  
Sepideh Kamrani
Keyword(s):  
Mechanical Milling ◽  
Volume Fraction ◽  
High Volume ◽  
Average Diameter ◽  
High Energy ◽  
Particle Size Analysis ◽  
Milling Process ◽  
Size Analysis ◽  
Magnesium Matrix ◽  
Nanocomposite Powders

Magnesium powder in micron scale and various volume fractions of SiC particles with an average diameter of 50 nm were co-milled by a high energy planetary ball mill for up to 25 h to produce Mg-SiC nanocomposite powders. The milled Mg-SiC nanocomposite powders were characterized by scanning electron microscopy (SEM) and laser particle size analysis (PSA) to study morphological evolutions. Furthermore, XRD, TEM, EDAX and SEM analyses were performed to investigate the microstructure of the magnesium matrix and distribution of SiC-reinforcement. It was shown that with addition of and increase in SiC nanoparticle content, finer particles with narrower size distribution are obtained after mechanical milling. The morphology of these particles also became more equiaxed at shorter milling times. The microstructural observation revealed that the milling process ensured uniform distribution of SiC nanoparticles in the magnesium matrix even with a high volume fraction, up to 10 vol%.

scholarly journals Near-Infrared Heterojunction Field Modulated Phototransistors with Distinct Photodetection/Photostorage Switching Feature for Artificial Visuals

2021 ◽  
Author(s):  
Jun Wang ◽  
Xiaoyang Du ◽  
Jiayue Han ◽  
Zhenghan Zhang ◽  
Zeyu He ◽  
...  
Keyword(s):  
Large Scale ◽  
Near Infrared ◽  
Memory Function ◽  
Optoelectronic Device ◽  
Vision Chip ◽  
Image Capture ◽  
Memory Switching ◽  
Solution Processes ◽  
Photo Response ◽  
Good Retention

Abstract With the rising demand of recording, computing and image capture, advanced optoelectronic detection, storage and logic devices are highly pursued. Nevertheless, multi-functional vision chip based on infrared detection and memory switching has never been demonstrated. Here, by utilizing the electronic extraction layer ZnO and face-on orientation of D-A, we exhibit the broadband visible to near-infrared photo-response and photo-storage characters on graphene phototransistor. Functions as photodetection and photo-storage can be switched with the variation of gate voltage. The device demonstrates high photo-responsivity up to 1.88 × 106 A/W at 895 nm corresponding detectivity of 4.8 × 1012 Jones. Importantly, the rewritable and switching infrared optoelectronic memory function can be achieved with good retention over 104 s. The both retinomorphic vision and memorial preprocessing in artificial visual are simultaneously realized by photodetection/photostorage switching property. Such nearly all-solution processes in our phototransistors may open up the path for the large-scale and easy manufacturing infrared multifunctional bio-optoelectronic device.

Dynamics of InAs Quantum Dots Formation on AlAs and GaAs

2000 ◽  
Vol 648 ◽  
Author(s):  
M. Yakimov ◽  
V. Tokranov ◽  
S. Oktyabrsky
Keyword(s):  
Quantum Dots ◽  
Self Assembly ◽  
Single Layer ◽  
High Energy ◽  
Ex Situ ◽  
Inas Quantum Dots ◽  
Force Microscopy ◽  
Atomic Force ◽  
Kinetics Of

AbstractWe have studied the formation of InAs quantum dots (QDs) grown by molecular beam epitaxy on top of GaAs and 2 ML-thick AlAs layers in the temperature range from 350 to 500°C. In-situ reflection high energy electron diffraction (RHEED) patterns were recorded in real time during the growth and analyzed to characterize the 2D-to-3D transition on the surface, including QD formation, and ripening process. The kinetics of QD formation was studied using the InAs growth rates ranging from 0.01 to 1 ML/s and different ratios of As2/In fluxes. RHEED patterns and ex-situ atomic force microscopy images were analyzed to reveal the development of sizes and shapes of the single-layer and stacked QD ensembles. The critical InAs coverage for QD formation was shown to be consistently higher for dots grown on the AlAs overlayer than for those grown on GaAs surface. Self-assembly of multilayer QD stacks revealed the reduction of the critical thickness for dots formed in the upper layers.

scholarly journals Glassy carbon manufacture using rapid photonic curing

2022 ◽  
Author(s):  
Brent de Boode ◽  
Chris Phillips ◽  
Yin Cheung Lau ◽  
Arturas Adomkevicius ◽  
James McGettrick ◽  
...  
Keyword(s):  
Glassy Carbon ◽  
Large Scale ◽  
Surface Defects ◽  
Local Environment ◽  
High Volume ◽  
High Energy ◽  
Carbon Coatings ◽  
Polymer Resin ◽  
Photonic Curing ◽  
Environment Temperature

AbstractPhotonic curing was explored as a rapid method for producing glassy carbon coatings, reducing processing time from ~ 20 h for conventional thermal processing down to ~ 1 min. A resole-type thermoset polymer resin coated on steel foil was used as a precursor, placed in a nitrogen purged container and exposed to high energy light (~ 27 J/cm2 per pulse for up to 20 pulses). Comparison samples were produced at 800 °C using a conventional nitrogen purged thermal route. For both photonic and conventionally produced coatings, Raman spectroscopy and primary peak XPS data showed sp2 bonded carbon, indicative of bulk glassy carbon. This transformation evolved with increasing number of pulses, and therefore amount of energy transferred to the coating. The produced coatings were resilient, highly smooth, with no evidence of surface defects. XPS analysis indicated greater sp3 content at the immediate surface (5–10 nm) for photonic cured carbon compared with thermally cured carbon, likely due to the local environment (temperature, atmosphere) around the surface during conversion. The ability to rapidly manufacture glassy carbon coatings provides new opportunities to expand the window of applications of glassy carbons in coatings towards large-scale high volume applications.

Transmission Electron Microscopy of Epitaxial silicides grown by ultra high vacuum deposition

1989 ◽  
Vol 47 ◽  
pp. 462-463
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
High Vacuum ◽  
High Energy ◽  
Energy Electron ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Transmission Electron

The silicides CoSi2 and NiSi2 are both metallic with the fee flourite structure and lattice constants which are close to silicon (1.2% and 0.6% smaller at room temperature respectively) Consequently epitaxial cobalt and nickel disilicide can be grown on silicon. If these layers are formed by ultra high vacuum (UHV) deposition (also known as molecular beam epitaxy or MBE) their thickness can be controlled to within a few monolayers. Such ultrathin metal/silicon systems have many potential applications: for example electronic devices based on ballistic transport. They also provide a model system to study the properties of heterointerfaces. In this work we will discuss results obtained using in situ and ex situ transmission electron microscopy (TEM).In situ TEM is suited to the study of MBE growth for several reasons. It offers high spatial resolution and the ability to penetrate many monolayers of material. This is in contrast to the techniques which are usually employed for in situ measurements in MBE, for example low energy electron diffraction (LEED) and reflection high energy electron diffraction (RHEED), which are both sensitive to only a few monolayers at the surface.

Organic solvent-assisted free-standing Li2MnO3·LiNi1/3Co1/3Mn1/3O2 on 3D graphene as a high energy density cathode

2015 ◽  
Vol 51 (91) ◽  
pp. 16381-16384 ◽  
Author(s):  
Yuelong Xin ◽  
Liya Qi ◽  
Yiwei Zhang ◽  
Zicheng Zuo ◽  
Henghui Zhou ◽  
...  
Keyword(s):  
Energy Density ◽  
Organic Solvent ◽  
Freeze Drying ◽  
Large Scale ◽  
High Energy ◽  
High Energy Density ◽  
Free Standing ◽  
3D Graphene ◽  
Active Particles

A novel organic solvent-assisted freeze-drying pathway, which can effectively protect and uniformly distribute active particles, is developed to fabricate a free-standing Li2MnO3·LiNi1/3Co1/3Mn1/3O2 (LR)/rGO electrode on a large scale.

scholarly journals An optical observational cluster mass function at z ∼ 1 with the ORELSE survey

2021 ◽  
Vol 502 (3) ◽  
pp. 3942-3954
Author(s):  
D Hung ◽  
B C Lemaux ◽  
R R Gal ◽  
A R Tomczak ◽  
L M Lubin ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Large Scale ◽  
Near Infrared ◽  
Function Analysis ◽  
Voronoi Tessellation ◽  
Cosmological Parameters ◽  
Mass Range ◽  
Mass Function ◽  
Cluster Mass ◽  
Theoretical Mass

ABSTRACT We present a new mass function of galaxy clusters and groups using optical/near-infrared (NIR) wavelength spectroscopic and photometric data from the Observations of Redshift Evolution in Large-Scale Environments (ORELSE) survey. At z ∼ 1, cluster mass function studies are rare regardless of wavelength and have never been attempted from an optical/NIR perspective. This work serves as a proof of concept that z ∼ 1 cluster mass functions are achievable without supplemental X-ray or Sunyaev-Zel’dovich data. Measurements of the cluster mass function provide important contraints on cosmological parameters and are complementary to other probes. With ORELSE, a new cluster finding technique based on Voronoi tessellation Monte Carlo (VMC) mapping, and rigorous purity and completeness testing, we have obtained ∼240 galaxy overdensity candidates in the redshift range 0.55 < z < 1.37 at a mass range of 13.6 < log (M/M⊙) < 14.8. This mass range is comparable to existing optical cluster mass function studies for the local universe. Our candidate numbers vary based on the choice of multiple input parameters related to detection and characterization in our cluster finding algorithm, which we incorporated into the mass function analysis through a Monte Carlo scheme. We find cosmological constraints on the matter density, Ωm, and the amplitude of fluctuations, σ8, of $\Omega _{m} = 0.250^{+0.104}_{-0.099}$ and $\sigma _{8} = 1.150^{+0.260}_{-0.163}$. While our Ωm value is close to concordance, our σ8 value is ∼2σ higher because of the inflated observed number densities compared to theoretical mass function models owing to how our survey targeted overdense regions. With Euclid and several other large, unbiased optical surveys on the horizon, VMC mapping will enable optical/NIR cluster cosmology at redshifts much higher than what has been possible before.

scholarly journals Creation of Negatively Charged Boron Vacancies in Hexagonal Boron Nitride Crystal by Electron Irradiation and Mechanism of Inhomogeneous Broadening of Boron Vacancy-Related Spin Resonance Lines

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1373
Author(s):  
Fadis F. Murzakhanov ◽  
Boris V. Yavkin ◽  
Georgiy V. Mamin ◽  
Sergei B. Orlinskii ◽  
Ivan E. Mumdzhi ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Electron Irradiation ◽  
Near Infrared ◽  
Hexagonal Boron Nitride ◽  
Optical Excitation ◽  
High Energy ◽  
Infrared Range ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Spin Resonance

Optically addressable high-spin states (S ≥ 1) of defects in semiconductors are the basis for the development of solid-state quantum technologies. Recently, one such defect has been found in hexagonal boron nitride (hBN) and identified as a negatively charged boron vacancy (VB−). To explore and utilize the properties of this defect, one needs to design a robust way for its creation in an hBN crystal. We investigate the possibility of creating VB− centers in an hBN single crystal by means of irradiation with a high-energy (E = 2 MeV) electron flux. Optical excitation of the irradiated sample induces fluorescence in the near-infrared range together with the electron spin resonance (ESR) spectrum of the triplet centers with a zero-field splitting value of D = 3.6 GHz, manifesting an optically induced population inversion of the ground state spin sublevels. These observations are the signatures of the VB− centers and demonstrate that electron irradiation can be reliably used to create these centers in hBN. Exploration of the VB− spin resonance line shape allowed us to establish the source of the line broadening, which occurs due to the slight deviation in orientation of the two-dimensional B-N atomic plains being exactly parallel relative to each other. The results of the analysis of the broadening mechanism can be used for the crystalline quality control of the 2D materials, using the VB− spin embedded in the hBN as a probe.

Sign in / Sign up

Export Citation Format

Share Document