scholarly journals Charge-polarized interfacial superlattices in marginally twisted hexagonal boron nitride

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
C. R. Woods ◽  
P. Ares ◽  
H. Nevison-Andrews ◽  
M. J. Holwill ◽  
R. Fabregas ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Electrostatic Force ◽  
Twist Angle ◽  
Force Microscopy ◽  
Transitional Metal ◽  
Close Proximity ◽  
Out Of Plane ◽  
Metal Dichalcogenides ◽  
Interfacial Surfaces

AbstractWhen two-dimensional crystals are brought into close proximity, their interaction results in reconstruction of electronic spectrum and crystal structure. Such reconstruction strongly depends on the twist angle between the crystals, which has received growing attention due to interesting electronic and optical properties that arise in graphene and transitional metal dichalcogenides. Here we study two insulating crystals of hexagonal boron nitride stacked at small twist angle. Using electrostatic force microscopy, we observe ferroelectric-like domains arranged in triangular superlattices with a large surface potential. The observation is attributed to interfacial elastic deformations that result in out-of-plane dipoles formed by pairs of boron and nitrogen atoms belonging to opposite interfacial surfaces. This creates a bilayer-thick ferroelectric with oppositely polarized (BN and NB) dipoles in neighbouring domains, in agreement with our modeling. These findings open up possibilities for designing van der Waals heterostructures and offer an alternative probe to study moiré-superlattice electrostatic potentials.

Atomic Force Microscopy study of hexagonal boron nitride film growth on 6H-SiC (0001)

2005 ◽  
Vol 202 (1) ◽  
pp. 3-3 ◽  
Author(s):  
Wei Chen ◽  
Kian Ping Loh ◽  
Ming Lin ◽  
Rong Liu ◽  
Andrew T. S. Wee
Keyword(s):  
Atomic Force Microscopy ◽  
Boron Nitride ◽  
Film Growth ◽  
Hexagonal Boron Nitride ◽  
Microscopy Study ◽  
Nitride Film ◽  
Atomic Force Microscopy Study ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Hexagonal Boron Nitride Tunnel Barriers Grown on Graphite by High Temperature Molecular Beam Epitaxy

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Yong-Jin Cho ◽  
Alex Summerfield ◽  
Andrew Davies ◽  
Tin S. Cheng ◽  
Emily F. Smith ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
High Temperature ◽  
Molecular Beam Epitaxy ◽  
Boron Nitride ◽  
Photoelectron Spectroscopy ◽  
Molecular Beam ◽  
Hexagonal Boron Nitride ◽  
Graphite Substrate ◽  
Force Microscopy ◽  
Atomic Force

Abstract We demonstrate direct epitaxial growth of high-quality hexagonal boron nitride (hBN) layers on graphite using high-temperature plasma-assisted molecular beam epitaxy. Atomic force microscopy reveals mono- and few-layer island growth, while conducting atomic force microscopy shows that the grown hBN has a resistance which increases exponentially with the number of layers, and has electrical properties comparable to exfoliated hBN. X-ray photoelectron spectroscopy, Raman microscopy and spectroscopic ellipsometry measurements on hBN confirm the formation of sp2-bonded hBN and a band gap of 5.9 ± 0.1 eV with no chemical intermixing with graphite. We also observe hexagonal moiré patterns with a period of 15 nm, consistent with the alignment of the hBN lattice and the graphite substrate.

scholarly journals Probing the Out-of-Plane Distortion of Single Point Defects in Atomically Thin Hexagonal Boron Nitride at the Picometer Scale

2011 ◽  
Vol 106 (12) ◽  
Author(s):  
Nasim Alem ◽  
Oleg V. Yazyev ◽  
Christian Kisielowski ◽  
P. Denes ◽  
Ulrich Dahmen ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Point Defects ◽  
Hexagonal Boron Nitride ◽  
Single Point ◽  
Out Of Plane

scholarly journals Epitaxy of highly ordered organic semiconductor crystallite networks supported by hexagonal boron nitride

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Aleksandar Matković ◽  
Jakob Genser ◽  
Daniel Lüftner ◽  
Markus Kratzer ◽  
Radoš Gajić ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Organic Semiconductors ◽  
Organic Semiconductor ◽  
Density Functional ◽  
Hexagonal Boron Nitride ◽  
Van Der Waals ◽  
Dielectric Substrate ◽  
Force Microscopy ◽  
Dielectric Substrates ◽  
Field Effect Devices

Abstract This study focuses on hexagonal boron nitride as an ultra-thin van der Waals dielectric substrate for the epitaxial growth of highly ordered crystalline networks of the organic semiconductor parahexaphenyl. Atomic force microscopy based morphology analysis combined with density functional theory simulations reveal their epitaxial relation. As a consequence, needle-like crystallites of parahexaphenyl grow with their long axes oriented five degrees off the hexagonal boron nitride zigzag directions. In addition, by tuning the deposition temperature and the thickness of hexagonal boron nitride, ordered networks of needle-like crystallites as long as several tens of micrometers can be obtained. A deeper understanding of the organic crystallites growth and ordering at ultra-thin van der Waals dielectric substrates will lead to grain boundary-free organic field effect devices, limited only by the intrinsic properties of the organic semiconductors.

scholarly journals Nanofriction characteristics of h-BN with electric field induced electrostatic interaction

Friction ◽  
2020 ◽  
Author(s):  
Kemeng Yu ◽  
Kun Zou ◽  
Haojie Lang ◽  
Yitian Peng
Keyword(s):  
Electric Field ◽  
Electrostatic Interaction ◽  
Hexagonal Boron Nitride ◽  
Electrostatic Force ◽  
Solid Lubricants ◽  
Conductive Atomic Force Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Graphene Devices ◽  
P Type

AbstractThe nanofriction properties of hexagonal boron nitride (h-BN) are vital for its application as a substrate for graphene devices and solid lubricants in micro- and nano-electromechanical devices. In this work, the nanofriction characteristics of h-BN on Si/SiO2 substrates with a bias voltage are explored using a conductive atomic force microscopy (AFM) tip sliding on the h-BN surface under different substrate bias voltages. The results show that the nanofriction on h-BN increases with an increase in the applied bias difference (Vt−s) between the conductive tip and the substrate. The nanofriction under negative Vt−s is larger than that under positive Vt−s. The variation in nanofriction is relevant to the electrostatic interaction caused by the charging effect. The electrostatic force between opposite charges localized on the conductive tip and at the SiO2/Si interface increases with an increase in Vt−s. Owing to the characteristics of p-type silicon, a positive Vt−s will first cause depletion of majority carriers, which results in a difference of nanofriction under positive and negative Vt−s. Our findings provide an approach for manipulating the nanofriction of 2D insulating material surfaces through an applied electric field, and are helpful for designing a substrate for graphene devices.

Hexagonal Boron Nitride Single Crystal Thermal Oxidation and Etching in Air: An Atomic Force Microscopy Study

MRS Advances ◽  
2019 ◽  
Vol 4 (10) ◽  
pp. 601-608
Author(s):  
N. Khan ◽  
E. Nour ◽  
J. Mondoux ◽  
S. Liu ◽  
J.H. Edgar ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Ambient Air ◽  
Microscopy Study ◽  
Deep Oxidation ◽  
Two Dimensional ◽  
Initial Oxidation ◽  
Force Microscopy ◽  
Atomic Force

ABSTRACTHexagonal boron nitride (hBN), a two dimensional (2D) material, has emerged as an important substrate and dielectric for electronic, optoelectronic, and photonic devices based on graphene and other atomically thin two dimensional materials. Here we report on the initial oxidation of (0001) hBN single crystals in ambient air as functions of temperature and time, as determined by atomic force microscopy (AFM) and scanning electron microscope with energy dispersive X-ray spectroscopy (SEM/EDS). For oxidation times of 20 minutes, the first evidence of oxidation appears at 900°C, with the formation of shallow, hexagonal-, and irregular-shaped pits that are less than 100 nm across and several nanometer deep. Oxidation at 1100°C for 20 minutes produced 1.0-2.0-micron size pits with flat and pointed bottoms that were approximately hexagonal-shaped, but with rough and irregular edges, and multiple interior steps. Oxidation was not uniform on the surface of hBN, but starts where dislocations in the crystal intersected the surfaces. Pit depth increased linearly with temperature and oxidation times. In addition to the surface pits, small particles formed on the surface. Elemental analysis of the thermally oxidized hBN crystals by SEM/EDS revealed the major elements of these particles were boron and oxygen.

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