Home > Press > Researchers integrate diamond/boron nitride crystalline layers for high-power devices
Raman spectra from diamond/c-BN single crystal films. |
Abstract:
“Direct Conversion of h-BN into c-BN and Formation of Epitaxial c-BN/Diamond Heterostructures”
Authors: Jagdish Narayan, Anagh Bhaumik, and Weizong Xu, North Carolina State University
Published: May 9, Journal of Applied Physics
DOI: 10.1063/1.4948688
Abstract: We have created a new state of BN (named Q-BN) through rapid melting and super undercooling and quenching by using nanosecond laser pulses. Phase pure c-BN is formed either by direct quenching of super undercooled liquid or by nucleation and growth from Q-BN. Thus a direct conversion of hexagonal boron nitride (h-BN) into phase-pure cubic boron nitride (c-BN) is achieved by nanosecond pulsed laser melting at ambient temperatures and atmospheric pressure in air. According to the P-T phase diagram, the transformation from h-BN into c-BN under equilibrium processing can occur only at high temperatures and pressures, as the hBN-cBN-Liquid triple point is at 3500K/9.5GPa or 3700K/7.0GPa with a recent theoretical refinement. Using nonequilibrium nanosecond laser melting, we have created super undercooled state and shifted this triple point to as low as 2800K and atmospheric pressure. The rapid quenching from super undercooled state leads to formation of a new phase, named as Q-BN. We present detailed characterization of Q-BN and c-BN layers by using Raman spectroscopy, high-resolution scanning electron microscopy, electron-back-scatter diffraction, HRTEM and electron energy loss spectroscopy, and discuss the mechanism of formation of nanodots, nanoneedles, microneedles, and single-crystal c-BN on sapphire substrate. We have also deposited diamond by pulsed laser deposition of carbon on c-BN and created c-BN/diamond heterostructures, where c-BN acts as a template for epitaxial diamond growth. We discuss the mechanism of epitaxial c-BN and diamond growth on lattice matching c-BN template under pulsed laser evaporation of amorphous carbon, and impact of this discovery on a variety of applications.
Materials researchers at North Carolina State University have developed a new technique to deposit diamond on the surface of cubic boron nitride (c-BN), integrating the two materials into a single crystalline structure.
“This could be used to create high-power devices, such as the solid state transformers needed to create the next generation ‘smart’ power grid,” says Jay Narayan, the John C. Fan Distinguished Chair Professor of Materials Science and Engineering at NC State and lead author of a paper describing the research.
“It could also be used to create cutting tools, high-speed machining and deep sea drilling equipment,” Narayan says. “Diamond is hard, but it tends to oxidize, transforming into graphite – which is softer. A coating of c-BN would prevent oxidation. Diamond also interacts with iron, making it difficult to use with steel tools. Again, c-BN would address the problem.”
C-BN is a form of boron nitride that has a cubic crystalline structure. It has similar properties to diamond, but holds several advantages: c-BN has a higher bandgap, which is attractive for use in high-power devices; c-BN can be “doped” to give it positively- and negatively-charged layers, which means it could be used to make transistors; and it forms a stable oxide layer on its surface when exposed to oxygen, making it stable at high temperatures. Earlier this year, Narayan unveiled a faster, less expensive technique for creating c-BN.
To create the epitaxial, or single crystal, diamond/c-BN structures, the researchers begin by creating a substrate of c-BN. This is done using the new technique Narayan published earlier this year. They then use a process called pulse-laser deposition – which is done at 500 degrees Celsius and an optimized atmospheric pressure – to deposit diamond on the surface of the c-BN. The pulse-laser technique allows them to control the thickness of the diamond layer.
“This is all done in a single chamber, making the process more energy- and time-efficient,” Narayan says. “You use only solid state carbon and BN, and it’s more environmentally benign than conventional techniques.”
The researchers were also able to deposit diamond on the c-BN using the conventional chemical vapor deposition technique, which utilizes methane gas, hydrogen gas and a tungsten filament at 900 °C.
“The chemical vapor deposition approach works, but our pulsed laser deposition approach works much better, doesn’t involve toxic gases, and can be done at much lower temperatures,” Narayan says.
Narayan has co-founded a company, Q-Carbon LLC, which has licensed the technique and is working to commercialize it for multiple applications.
####
For more information, please click here
Contacts:
Matt Shipman
919-515-6386
Copyright © North Carolina State University
If you have a comment, please Contact us.Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Related Links |
Related News Press |
News and information
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Mining/Extraction/Drilling
Chile coating and composite industry makes leap forward leveraging graphene nanotube solutions April 9th, 2021
Membrane technology could cut emissions and energy use in oil refining July 17th, 2020
Extraction of lithium from its largest source, i.e. seawater, by nanostructured membranes January 27th, 2020
Govt.-Legislation/Regulation/Funding/Policy
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
Possible Futures
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
With VECSELs towards the quantum internet Fraunhofer: IAF achieves record output power with VECSEL for quantum frequency converters April 5th, 2024
Discoveries
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
New micromaterial releases nanoparticles that selectively destroy cancer cells April 5th, 2024
Utilizing palladium for addressing contact issues of buried oxide thin film transistors April 5th, 2024
Materials/Metamaterials/Magnetoresistance
Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024
Focused ion beam technology: A single tool for a wide range of applications January 12th, 2024
Announcements
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Tools
Ferroelectrically modulate the Fermi level of graphene oxide to enhance SERS response November 3rd, 2023
The USTC realizes In situ electron paramagnetic resonance spectroscopy using single nanodiamond sensors November 3rd, 2023
Patents/IP/Tech Transfer/Licensing
Getting drugs across the blood-brain barrier using nanoparticles March 3rd, 2023
Metasurfaces control polarized light at will: New research unlocks the hidden potential of metasurfaces August 13th, 2021
Arrowhead Pharmaceuticals Announces Closing of Agreement with Takeda November 27th, 2020
The latest news from around the world, FREE | ||
Premium Products | ||
Only the news you want to read!
Learn More |
||
Full-service, expert consulting
Learn More |
||