scholarly journals Synthesis of Three-Dimensionally Interconnected Hexagonal Boron Nitride Networked Cu-Ni Composite

2021 ◽  
Vol 59 (7) ◽  
pp. 505-513
Author(s):  
Zahid Hussain ◽  
Hye-Won Yang ◽  
Byung-Sang Choi
Keyword(s):  
Electron Microscopy ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Compaction Pressure ◽  
Chemical Properties ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Transmission Electron ◽  
Ni Alloy ◽  
Composite Energy

A three-dimensionally interconnected hexagonal boron nitride (3Di-hBN) networked Cu-Ni (3DihBN-Cu-Ni) composite was successfully synthesized in situ using a simple two-step process which involved the compaction of mixed Cu-Ni powders (70 wt.% Cu and 30 wt.% Ni) into a disc followed by metal-organic chemical vapor deposition (MOCVD) at 1000 oC. During MOCVD, the Cu-Ni alloy grains acted as a template for the growth of hexagonal boron nitride (hBN) while decaborane and ammonia were used as precursors for boron and nitrogen, respectively. Boron and nitrogen atoms diffused into the Cu-Ni solution during the MOCVD process and precipitated out along the Cu-Ni interfaces upon cooling, resulting in the formation of the 3Di hBN-Cu-Ni composite. Energy-dispersive spectroscopic analysis confirmed the presence of boron and nitrogen atoms at the interfaces of Cu-Ni alloy grains. Optical microscopy examination indicated that there was a minimum amount of bulk hBN at a certain compaction pressure (280 MPa) and sintering time (30 min). Scanning electron microscopy and transmission electron microscopy revealed that an interconnected network of hBN layers surrounding the Cu-Ni grains developed in the 3Di-hBN-Cu-Ni composite. This 3Di-hBN network is expected to enhance the mechanical, thermal, and chemical properties of the 3Di-hBN-Cu-Ni composite. Moreover, the foam-like 3Di-hBN extracted from 3Di-hBN-Cu-Ni composite could have further applications in the fields of biomedicine and energy storage.

scholarly journals High-Yield Synthesis of Cubic and Hexagonal Boron Nitride Nanoparticles by Laser Chemical Vapor Decomposition of Borazine

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
A. Hidalgo ◽  
V. Makarov ◽  
G. Morell ◽  
B. R. Weiner
Keyword(s):  
Electron Microscopy ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Chemical Vapor ◽  
High Yield ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Chemical Vapor Decomposition ◽  
Electron Energy Loss ◽  
Bn Nanostructures

We report a new method for the synthesis of boron nitride nanostructures (nBN) using laser chemical vapor decomposition (LCVD). Borazine was used as precursor and excited with two simultaneous radiations, the fundamental and second YAG laser harmonics. If only one of the two radiations is employed, no reaction takes place. Abundant BN powder is obtained after one hour of laser radiation. The BN yield obtained with the LCVD technique is about 83% by weight. The BN material was characterized using scanning electron microscopy, transmission electron microscopy, electron energy loss spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. They all indicate that the BN powder consists of a mixture of hexagonal and cubic BN nanostructures. No other BN phases or stoichiometries were found. The size of the resulting BN nanostructures is in the range of 20–100 nm and their B : N composition is 1 : 1. A simplified mechanism involving laser-excited states followed by photoinduced removal of hydrogen is proposed to understand the synthesis of BN nanopowder by LCVD of borazine.

Characterization of Highly Textured PZT Thin Films Grown on LaNiO3 Coated Si Substrates by MOCVD

1997 ◽  
Vol 493 ◽  
Author(s):  
C. H. Lin ◽  
B. M. Yen ◽  
Haydn Chen ◽  
T. B. Wu ◽  
H. C. Kuo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Fatigue Behavior ◽  
Chemical Vapor ◽  
Dielectric Constants ◽  
Preferential Orientation ◽  
Organic Chemical ◽  
Pzt Thin Films ◽  
Si Substrates ◽  
Transmission Electron

ABSTRACTHighly textured PbZrxTi1−xO3 (PZT) thin films with x= 0-0.6 were grown on LaNiO3 coated Si substrates at 600 °C by metal-organic chemical vapor deposition (MOCVD). The preferred crystalline orientation of PZT thin films with various Zr concentration were characterized by X-ray diffraction (XRD). Microstructures were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The dielectric constants, hysteresis and fatigue behavior of these thin films were also measured. The relationship between growth rate and the preferential orientation is discussed. Furthermore, the dependence of the electrical properties on Zr concentration and preferential orientation is demonstrated.

Microstructural Characterization of GaN Grown on SiC

2019 ◽  
Vol 25 (6) ◽  
pp. 1383-1393
Author(s):  
Sabyasachi Saha ◽  
Deepak Kumar ◽  
Chandan K. Sharma ◽  
Vikash K. Singh ◽  
Samartha Channagiri ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Raman Spectroscopy ◽  
Surface Morphology ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
Organic Chemical ◽  
Nucleation Layer ◽  
Transmission Electron ◽  
Vapor Deposition Technique ◽  
Metal Organic

AbstractGaN films have been grown on SiC substrates with an AlN nucleation layer by using a metal organic chemical vapor deposition technique. Micro-cracking of the GaN films has been observed in some of the grown samples. In order to investigate the micro-cracking and microstructure, the samples have been studied using various characterization techniques such as optical microscopy, atomic force microscopy, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy (TEM). The surface morphology of the AlN nucleation layer is related to the stress evolution in subsequent overgrown GaN epilayers. It is determined via TEM evidence that, if the AlN nucleation layer has a rough surface morphology, this leads to tensile stresses in the GaN films, which finally results in cracking. Raman spectroscopy results also suggest this, by showing the existence of considerable tensile residual stress in the AlN nucleation layer. Based on these various observations and results, conclusions or propositions relating to the microstructure are presented.

scholarly journals Catalyst-Free Bottom-Up Synthesis of Few-Layer Hexagonal Boron Nitride Nanosheets

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Shena M. Stanley ◽  
Amartya Chakrabarti ◽  
Joshua J. DeMuth ◽  
Vanessa E. Tempel ◽  
Narayan S. Hosmane
Keyword(s):  
Electron Microscopy ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
X Ray Diffraction ◽  
Bottom Up ◽  
X Ray ◽  
Boron Nitride Nanosheets ◽  
Catalyst Free ◽  
Transmission Electron ◽  
Novel Catalyst

A novel catalyst-free methodology has been developed to prepare few-layer hexagonal boron nitride nanosheets using a bottom-up process. Scanning electron microscopy and transmission electron microscopy (both high and low resolution) exhibit evidence of less than ten layers of nanosheets with uniform dimension. X-ray diffraction pattern and other additional characterization techniques prove crystallinity and purity of the product.

scholarly journals Atomic-scale dynamics of triangular hole growth in monolayer hexagonal boron nitride under electron irradiation

Nanoscale ◽  
2015 ◽  
Vol 7 (24) ◽  
pp. 10600-10605 ◽  
Author(s):  
Gyeong Hee Ryu ◽  
Hyo Ju Park ◽  
Junga Ryou ◽  
Jinwoo Park ◽  
Jongyeong Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Boron Nitride ◽  
Electron Beam Irradiation ◽  
Hexagonal Boron Nitride ◽  
Atomic Scale ◽  
Atomic Resolution ◽  
Beam Irradiation ◽  
Transmission Electron ◽  
Hole Growth ◽  
Over Time

The production of holes by electron beam irradiation in hexagonal boron nitride is monitored over time using atomic resolution transmission electron microscopy.

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