Chinese Physics Letters,
Год журнала:
2023,
Номер
40(6), С. 067801 - 067801
Опубликована: Май 1, 2023
Optical
fine-tunable
layer-hybridized
Moiré
excitons
are
highly
in
demand
for
emerging
many-body
states
two-dimensional
semiconductors.
We
report
naturally
confined
bright
with
long
lifetimes
twisted
hexagonal
GaTe
bilayers,
using
ab
initio
perturbation
theory
and
the
Bethe–Salpeter
equation.
Due
to
hybridization
of
electrons
holes
between
layers,
which
enhances
brightness
excitons,
bilayer
system
becomes
attractive
optical
applications.
find
that
both
R
H-type
stacking
superlattices,
more
than
200
meV
lateral
quantum
confinements
occur
on
exciton
energies,
results
two
scenarios:
(1)
The
ground
state
X
A
found
be
trapped
at
high-symmetry
points,
opposite
electric
dipoles
R-stacking
supercell,
forming
a
honeycomb
superlattice
nearest-neighbor
dipolar
attraction.
(2)
For
H-stacking
case,
is
only
one
point
exhibiting
triangular
superlattice.
Our
suggest
h-GaTe
promising
systems
excitonic
devices
provide
an
ideal
platform
realizing
strong
correlated
Bose–Hubbard
physics.
ACS Nano,
Год журнала:
2023,
Номер
17(3), С. 2472 - 2486
Опубликована: Янв. 17, 2023
Energetic
processing
methods
such
as
hyperthermal
implantation
hold
special
promise
to
achieve
the
precision
synthesis
of
metastable
two-dimensional
(2D)
materials
Janus
monolayers;
however,
they
require
precise
control.
Here,
we
report
a
feedback
approach
reveal
and
control
transformation
pathways
in
by
pulsed
laser
deposition
(PLD)
apply
it
investigate
kinetics
monolayer
WS2
crystals
into
WSSe
WSe2
Se
clusters
with
different
maximum
kinetic
energies
(<42
eV/Se-atom)
generated
ablation
target.
Real-time
Raman
spectroscopy
photoluminescence
are
used
assess
structure,
composition,
optoelectronic
quality
crystal
is
implanted
well-controlled
fluxes
selenium
for
that
regulated
situ
ICCD
imaging,
ion
probe,
diagnostics.
First-principles
calculations,
XPS,
atomic-resolution
HAADF
STEM
imaging
understand
intermediate
alloy
compositions
their
vibrational
modes
identify
pathways.
The
real-time
measurements
highly
selective
top-layer
conversion
transforms
through
WS2(1-x)Se2x
alloys
provide
means
adjust
conditions
fractional
complete
monolayers
transition
states.
general
demonstrates
method
layers
or
other
desired
structure
grown
PLD,
addressing
priority
research
directions
adaptive
Nanophotonics,
Год журнала:
2025,
Номер
14(10), С. 1475 - 1507
Опубликована: Март 10, 2025
Abstract
Over
the
past
two
decades,
two-dimensional
(2D)
van
der
Waals
(vdW)
semiconductors
have
garnered
significant
attention
in
field
of
light
sources
due
to
their
unique
optoelectronic
properties,
such
as
high
excitonic
binding
energy,
tunable
bandgaps,
and
strong
optical
anisotropy.
These
properties
make
2D
vdW
highly
promising
for
next-generation
sources,
offering
advantages
like
enhanced
efficiency,
wavelength
tunability,
polarization
control.
In
this
review,
we
summarize
development
various
material-based
modulation
mechanisms.
We
first
provide
an
overview
light-emission
principles
that
aim
develop
with
low-power,
high-efficiency.
Next,
discuss
advances
semiconductor
lasers,
including
intralayer
interlayer
exciton
cavity-free
systems,
exciton-polariton
sources.
then
look
into
single-photon
emission
integration
on-chip
followed
by
studies
on
nonlinear
high-order
harmonic
generation
P-band
emission.
Additionally,
cover
advancements
electrically
pumped
The
review
concludes
outlook
future
developments
Physical Review Materials,
Год журнала:
2023,
Номер
7(10)
Опубликована: Окт. 3, 2023
The
accurate
description
of
electronic
properties
and
optical
absorption
spectra
is
a
long-standing
challenge
for
density
functional
theory.
Recently,
the
introduction
screened
range-separated
hybrid
(SRSH)
functionals
solid-state
materials
has
allowed
calculation
fundamental
band
gaps
that
are
in
very
good
agreement
with
many-body
perturbation
However,
since
SRSH
typically
tuned
to
reproduce
bulk
phases,
their
transferability
low-dimensional
structures,
which
experience
substantially
different
screening
than
bulk,
remains
an
open
question.
In
this
work,
we
explore
several
prototypical
van
der
Waals
materials,
including
transition-metal
sulfides
selenides,
indium
selenide,
black
phosphorus,
hexagonal
boron
nitride.
Considering
monolayer
these
as
limiting
cases,
show
parameters
can
be
determined
systematically,
using
only
band-edge
quasiparticle
energies
extremal
structural
phases
fitting
targets.
resulting
describe
both
structures
accuracy
comparable
more
demanding
ab
initio
theory
(GW
Bethe-Salpeter
equation)
approaches.
Selected
examples
also
demonstrate
parameters,
obtained
from
reference
display
bilayers,
indicating
degree
independent
procedure.
Journal of Chemical Theory and Computation,
Год журнала:
2024,
Номер
20(6), С. 2349 - 2361
Опубликована: Март 16, 2024
Proper
construction
of
the
density
matrix
based
on
surface
hopping
trajectories
remains
a
difficult
problem.
Due
to
well-known
overcoherence
in
traditional
simulations,
electronic
wave
function
cannot
be
used
directly.
In
this
work,
we
propose
consistent
method,
which
takes
advantage
occupation
active
states
rescale
coherence
calculated
by
functions
and
ensures
intrinsic
consistency
matrix.
This
new
trajectory
analysis
method
can
for
both
Tully's
fewest
switches
(FSSH)
our
recently
proposed
branching
corrected
(BCSH).
As
benchmarked
one-
two-dimensional
standard
scattering
models,
approach
combined
with
BCSH
achieves
highly
accurate
time-dependent
spatial
distributions
adiabatic
populations
compared
exact
quantum
results.
Advanced Optical Materials,
Год журнала:
2023,
Номер
11(19)
Опубликована: Авг. 1, 2023
Abstract
Janus
transition
metal
dichalcogenides
are
an
emerging
class
of
atomically
thin
materials
with
engineered
broken
mirror
symmetry
that
gives
rise
to
long‐lived
dipolar
excitons,
Rashba
splitting,
and
topologically
protected
solitons.
They
hold
great
promise
as
a
versatile
nonlinear
optical
platform
due
their
broadband
harmonic
generation
tunability,
ease
integration
on
photonic
structures,
nonlinearities
beyond
the
basal
crystal
plane.
Here,
second
third
in
MoSSe
WSSe
monolayers
is
studied.
Polarization‐resolved
spectroscopy
used
map
full
second‐order
susceptibility
tensor
MoSSe,
including
its
out‐of‐plane
components.
In
addition,
effective
third‐order
dispersion
close
exciton
resonances
for
both
measured
at
room
cryogenic
temperatures.
This
work
sets
bedrock
understanding
properties
probing
use
next‐generation
on‐chip
multifaceted
devices.
Exciton-exciton
interactions
are
key
to
understanding
nonlinear
optical
and
transport
phenomena
in
van
der
Waals
heterobilayers,
which
emerged
as
versatile
platforms
study
correlated
electronic
states.
We
present
a
combined
theory-experiment
of
excitonic
many-body
effects
based
on
first-principle
band
structures
Coulomb
interaction
matrix
elements.
Key
our
approach
is
the
explicit
treatment
fermionic
substructure
excitons
dynamical
screening
for
density-induced
energy
renormalization
dissipation.
demonstrate
that
dipolar
blueshifts
almost
perfectly
compensated
by
effects,
mainly
screening-induced
self-energy
corrections.
Moreover,
we
identify
crossover
between
attractive
repulsive
behavior
at
elevated
exciton
densities.
Theoretical
findings
supported
experimental
studies
spectrally
narrow,
mobile
interlayer
atomically
reconstructed,
h-BN-encapsulated
MoSe2/WSe2
heterobilayers.
Both
theory
experiment
show
scale
few
meV
even
high
injection
densities
vicinity
Mott
transition.
Our
results
revise
established
picture
repulsion
dominating
exciton-exciton
heterostructures
open
up
opportunities
their
external
design.
Published
American
Physical
Society
2024
Abstract
Janus
transition
metal
dichalcogenides
(TMDs)
are
a
novel
class
of
2D
materials
with
unique
mirror
asymmetry.
Plasma‐assisted
synthesis
at
room
temperature
is
favored
for
producing
TMDs
due
to
its
energy
efficiency
and
prevention
alloying.
However,
current
methods
require
stringent
control
over
growth
conditions,
risking
defects
or
unintended
materials.
A
robust
plasma‐assisted
(RPA)
strategy
introduced,
incorporating
built‐in
tube
suitable
inner
diameter
into
the
system.
This
innovation
creates
mild,
uniform
plasma
atmosphere,
allowing
broader
variations
in
parameters
without
significantly
affecting
MoSSe's
morphology
characteristics.
approach
simplifies
process
enhances
success
rate
TMD
production.
Additionally,
explored
enhance
photoluminescence
(PL)
MoSSe.
Releasing
MoSSe
from
substrate
annealing
it
removes
strain
unintentional
doping,
improving
PL
performance.
on
hexagonal
boron
nitride
(
h
‐BN)
flakes
after
shows
32‐fold
increase
intensity.
Bis(trifluoromethane)
sulfonimide
(TFSI)
treatment
results
remarkable
70‐fold
intensity,
2.5‐fold
extension
exciton
lifetime,
quantum
yield
(QY)
reaching
up
≈31.2%.
These
findings
provide
critical
insights
optimizing
luminescence
properties
materials,
advancing
optoelectronics.
