Submillimeter Optical Properties of Hexagonal Boron Nitride

1992 ◽  
Vol 242 ◽  
Author(s):  
A. J. Gatesman ◽  
R. H. Giles ◽  
J. Waldman
Keyword(s):  
Optical Properties ◽  
Boron Nitride ◽  
Room Temperature ◽  
Hexagonal Boron Nitride ◽  
Fourier Transform Spectrometer ◽  
Hexagonal Crystal Structure ◽  
Hexagonal Crystal ◽  
Absorption Properties ◽  
Birefringent Crystal ◽  
A Value

ABSTRACTThe submillimeter optical properties of hot-pressed boron nitride with a hexagonal crystal structure were studied at room temperature from approximately 20 cm-1 to 120 cm-1 (500μm -84 μm) with a Fourier Transform Spectrometer. Several grades were studied and probed both parallel and perpendicular to the material's optic axis. The material was found to behave as a negatively uniaxial birefringent crystal. In one case, the birefringence (Δ = ne - no) was quite large with a value of-0.152. The material's absorption properties were also studied. For certain grades, a modest dichroism was observed. The low absorption (α < 1 cm-1) for grade A at frequencies below 38 cm-1 suggests the possibility for millimeter/submillimeter wave applications. Results are compared with data by other researchers on related materials.

scholarly journals Controlled generation of luminescent centers in hexagonal boron nitride by irradiation engineering

2021 ◽  
Vol 7 (8) ◽  
pp. eabe7138
Author(s):  
M. Fischer ◽  
J. M. Caridad ◽  
A. Sajid ◽  
S. Ghaderzadeh ◽  
M. Ghorbani-Asl ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Optical Properties ◽  
Kinetic Energy ◽  
Boron Nitride ◽  
Ab Initio Calculations ◽  
Room Temperature ◽  
Hexagonal Boron Nitride ◽  
Two Dimensional ◽  
Dynamics Simulations ◽  
Luminescent Centers

Luminescent centers in the two-dimensional material hexagonal boron nitride have the potential to enable quantum applications at room temperature. To be used for applications, it is crucial to generate these centers in a controlled manner and to identify their microscopic nature. Here, we present a method inspired by irradiation engineering with oxygen atoms. We systematically explore the influence of the kinetic energy and the irradiation fluence on the generation of luminescent centers. We find modifications of their density for both parameters, while a fivefold enhancement is observed with increasing fluence. Molecular dynamics simulations clarify the generation mechanism of these centers and their microscopic nature. We infer that VNCB and VB− are the most likely centers formed. Ab initio calculations of their optical properties show excellent agreement with our experiments. Our methodology generates quantum emitters in a controlled manner and provides insights into their microscopic nature.

Room temperature spin valve effect in the NiFe/Gr–hBN/Co magnetic tunnel junction

2016 ◽  
Vol 4 (37) ◽  
pp. 8711-8715 ◽  
Author(s):  
Muhammad Zahir Iqbal ◽  
Salma Siddique ◽  
Ghulam Hussain ◽  
Muhammad Waqas Iqbal
Keyword(s):  
Boron Nitride ◽  
Tunnel Junction ◽  
Room Temperature ◽  
Hexagonal Boron Nitride ◽  
Spin Valve ◽  
Magnetic Tunnel Junction ◽  
Valve Effect ◽  
First Time

Graphene and hexagonal boron nitride (hBN) have shown fascinating features in spintronics due to their metallic and tunneling behaviors, respectively. In this work, we report for the first time room temperature spin valve effect in NiFe/Gr–hBN/Co configuration.

Tuning the electronic and optical properties of hexagonal boron-nitride nanosheet by inserting graphene quantum dots

2018 ◽  
Vol 32 (06) ◽  
pp. 1850084 ◽  
Author(s):  
Yi-Min Ding ◽  
Jun-Jie Shi ◽  
Min Zhang ◽  
Meng Wu ◽  
Hui Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Graphene Quantum Dots ◽  
Band Gaps ◽  
Hybrid Structures ◽  
Electronic And Optical Properties ◽  
Boron Nitride Nanosheet ◽  
Optoelectronic Nanodevices

It is difficult to integrate two-dimensional (2D) graphene and hexagonal boron-nitride (h-BN) in optoelectronic nanodevices, due to the semi-metal and insulator characteristic of graphene and h-BN, respectively. Using the state-of-the-art first-principles calculations based on many-body perturbation theory, we investigate the electronic and optical properties of h-BN nanosheet embedded with graphene dots. We find that C atom impurities doped in h-BN nanosheet tend to phase-separate into graphene quantum dots (QD), and BNC hybrid structure, i.e. a graphene dot within a h-BN background, can be formed. The band gaps of BNC hybrid structures have an inverse relationship with the size of graphene dot. The calculated optical band gaps for BNC structures vary from 4.71 eV to 3.77 eV, which are much smaller than that of h-BN nanosheet. Furthermore, the valence band maximum is located in C atoms bonded to B atoms and conduction band minimum is located in C atoms bonded to N atoms, which means the electron and hole wave functions are closely distributed around the graphene dot. The bound excitons, localized around the graphene dot, determine the optical spectra of the BNC hybrid structures, in which the exciton binding energies decrease with increase in the size of graphene dots. Our results provide an important theoretical basis for the design and development of BNC-based optoelectronic nanodevices.

Tribological and Corrosion Behavior of HVOF Sprayed Cr3C2-NiCr with Nickel Cladded Graphite and Hexagonal Boron Nitride

2021 ◽  
Author(s):  
M. Oechsner ◽  
T. Engler ◽  
H. Scheerer ◽  
Y. Joung ◽  
K. Bobzin ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Friction And Wear ◽  
Room Temperature ◽  
Solid Lubricant ◽  
Hexagonal Boron Nitride ◽  
Solid Lubricants ◽  
Wear Behaviour ◽  
Wear Volume ◽  
Coating Microstructure ◽  
Sprayed Coatings

Abstract High-velocity oxyfuel (HVOF) sprayed coatings of Cr3C2-NiCr containing solid lubricants such as nickel cladded graphite and hexagonal boron nitride were successfully developed and characterised with the aim of optimizing their friction and wear behaviour. HVOF technology was used for the integration of solid lubricants to achieve strong cohesion between particles while minimizing thermal decomposition. Coating microstructure and composition were measured and correlated to the results of tribological and corrosion tests. The integration of the solid lubricant greatly reduced friction and wear volume at room temperature, but the lubricating effect was highly dependent on atmosphere and temperature. Cr3C2-NiCr with hBN, however, tends to exhibit more stable wear resistance over a wider temperature range and can be used at temperatures beyond 450 °C.

scholarly journals Effect of growth temperature on the structural and optical properties of few-layer hexagonal boron nitride by molecular beam epitaxy

2018 ◽  
Vol 26 (18) ◽  
pp. 23031 ◽  
Author(s):  
David Arto Laleyan ◽  
Kelsey Mengle ◽  
Songrui Zhao ◽  
Yongjie Wang ◽  
Emmanouil Kioupakis ◽  
...  
Keyword(s):  
Optical Properties ◽  
Molecular Beam Epitaxy ◽  
Boron Nitride ◽  
Growth Temperature ◽  
Molecular Beam ◽  
Hexagonal Boron Nitride ◽  
Structural And Optical Properties

Unraveling the optical properties of hexagonal boron nitride

SPIE Newsroom ◽  
2016 ◽  
Author(s):  
Guillaume Cassabois ◽  
Pierre Valvin ◽  
Bernard Gil
Keyword(s):  
Optical Properties ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride

Formation of quantum emitter arrays in hexagonal Boron Nitride at room temperature

2018 ◽  
Author(s):  
Nicholas V Proscia ◽  
Zav Shoton ◽  
Harishankar Jayakumar ◽  
Prithvi Reddy ◽  
Michael Dollar ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Room Temperature ◽  
Hexagonal Boron Nitride ◽  
Quantum Emitter
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