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@article{WOS:001701838600001,
title = {Surface defects in carbon-doped hexagonal boron nitride for
negative-contrast direct laser writing},
author = {Dmitrii Litvinov and Virgil Gavriliuc and Magdalena Grzeszczyk and Kristina Vaklinova and Kenji Watanabe and Takashi Taniguchi and Kostya S Novoselov and Maciej Koperski},
doi = {10.1088/2053-1583/ae463c},
times_cited = {0},
issn = {2053-1583},
year = {2026},
date = {2026-06-01},
journal = {2D MATERIALS},
volume = {13},
number = {2},
publisher = {IOP Publishing Ltd},
address = {No.2 The Distillery, Glassfields, Avon Street, Bristol, ENGLAND},
abstract = {Radiative defects in hexagonal boron nitride (hBN) are active in a broad
spectral range from deep ultraviolet to near-infrared wavelengths.
Representatives of these defects act as bright single photon sources,
spin-1 systems, and multiproperty atomic-scale sensors. They are
predominantly investigated in bulk hBN films, where defects are
decoupled from surface and interfacial effects. Here, we demonstrate a
novel class of surface defects optically active in the green/yellow
visible spectral range, which exhibit photophysical properties distinct
from their bulk counterparts. High-power resonant laser illumination
quenched the emission from the ensemble of such defects, which was
attributed to a light-driven structural reconfiguration. The quenched
defects were found to recover their emissive capabilities via a thermal
cycling process, revealing an activation energy of 24.5 meV for the
structural transition. Alternatively, permanent quenching of the defects
was triggered by surface chemistry, involving lithiation-enabled
attachment of functional groups. These mechanisms were utilized to
realize negative-contrast direct laser writing, designing arbitrary
geometric emissive patterns on demand in a microscopic configuration.
The surface-active radiative centers in hBN appear particularly
attractive for exploring environmental sensitivity, surface science, and
coupling to photonic structures or electronic devices by taking unique
advantage of the two-dimensional characteristics of the host lattice.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{WOS:001825334700001,
title = {Polymer-free van der Waals assembly of 2D material heterostructures
using muscovite crystals},
author = {Ian Babich and Timofey M Savilov and Natalia A Mamchik and Kristina Vaklinova and Nansi Zhou and Denis S Baranov and Dmitrii A Litvinov and Virgil Gavriliuc and Yue Yuan and Amoz Chua and Kenji Watanabe and Takashi Taniguchi and Mario Lanza and Maciej Koperski and Kostya S Novoselov and Alexey I Berdyugin and Makars Siskins},
doi = {10.1038/s41467-026-72554-x},
times_cited = {4},
year = {2026},
date = {2026-05-01},
journal = {NATURE COMMUNICATIONS},
volume = {17},
number = {1},
publisher = {NATURE PORTFOLIO},
address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},
abstract = {The advent of van der Waals (vdW) heterostructures has enabled formation
of bespoke materials with atomic precision, where numerous quantum and
topological phenomena have already been discovered. This atomic-layer
tunability, however, comes at a cost: individual 2D layers must be
picked up, moved, and placed in a deterministic manner while keeping
their interfaces atomically clean. Recent advances in machine learning
and robotics place even stronger emphasis on the deterministic aspect of
vdW assembly. Current polymer-based transfer methods satisfy neither the
determinism nor cleanliness requirements. To this end, solutions are
needed where adhesion can be dynamically and deterministically
controlled without leaving organic contamination. Here, we present a
polymer-free transfer technique employing thin muscovite (mica)
crystals. Temperature control over mica adhesion enables deterministic
pick-up, stacking, and release of 2D materials, while their crystalline,
inorganic nature ensures pristine interfaces and suppresses strain.
Fully compatible with existing fabrication workflows, this approach
enables the assembly of demanding vdW heterostructures, including those
with exposed conductive layers, moir & eacute; superlattices and
suspended membranes. Our method represents a promising strategy for vdW
heterostructure fabrication toward its automatisation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{WOS:001634241900001,
title = {Electrically modulated light-emitting device driven by resonant and
antiresonant tunneling between
Cr2Ge2Te6 electrodes},
author = {Natalia Zawadzka and Kristina Vaklinova and Tomasz Wozniak and Mihai Sturza I and Holger Kohlmann and Kenji Watanabe and Takashi Taniguchi and Adam Babinski and Maciej Koperski and Maciej R Molas},
doi = {10.1088/2053-1583/ae2520},
times_cited = {1},
issn = {2053-1583},
year = {2026},
date = {2026-03-01},
journal = {2D MATERIALS},
volume = {13},
number = {1},
publisher = {IOP Publishing Ltd},
address = {No.2 The Distillery, Glassfields, Avon Street, Bristol, ENGLAND},
abstract = {Exploring the electron tunneling mechanisms in diverse materials systems
constitutes a versatile strategy for tailoring the properties of
optoelectronic devices. In this domain, bipolar vertical tunneling
junctions composed of van der Waals materials with vastly different
electronic band structures enable simultaneous injection of electrons
and holes into an optically active material, providing a universal
blueprint for light-emitting devices. Efficient modulation of the
injection efficiency has previously been demonstrated by creating
resonant states within the energy barrier formed by the luminescent
material. Here, we present an alternative approach towards resonant
tunneling conditions by fabricating tunneling junctions composed
entirely from gapped materials: Cr2Ge2Te6 as electrodes, hBN as a
tunneling barrier, and monolayer WSe2 as a luminescent medium. The
characterization of such light-emitting tunneling structure revealed a
nonmonotonous evolution of the electroluminescence intensity with the
tunneling bias. The dominant role driving the characteristics of the
electron tunneling was associated with the relative alignment of the
density of states in Cr2Ge2Te6 electrodes. The unique device
architecture introduced here presents a universal pathway towards
electroluminescent devices operating at room temperature with
electrically modulated emission intensity.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{WOS:001541286100001,
title = {Interplay between charge transfer and magnetic proximity effects in
WSe2/CrCl3 heterostructures},
author = {Lucja Kipczak and Zhaolong Chen and Magdalena Grzeszczyk and Sergey Grebenchuk and Pengru Huang and Kristina Vaklinova and Kenji Watanabe and Takashi Taniguchi and Adam Babinski and Maciej Koperski and Maciej R Molas},
doi = {10.1039/d5nh00198f},
times_cited = {5},
issn = {2055-6756},
year = {2025},
date = {2025-09-01},
journal = {NANOSCALE HORIZONS},
volume = {10},
number = {10},
pages = {2465-2474},
publisher = {ROYAL SOC CHEMISTRY},
address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS,
ENGLAND},
abstract = {Ferromagnetism in van der Waals systems with diverse spin arrangements
opened a pathway to use proximity magnetic fields to activate the
properties of materials that would otherwise require external stimuli.
Herein, we demonstrate this concept by creating heterostructures
comprising a bulk CrCl3 antiferromagnet with in-plane easy-axis
magnetization and a monolayer (ML) WSe2 semiconductor. Photoluminescence
and magnetic force microscopy techniques were performed to reveal the
interaction between the relevant layers in the WSe2/CrCl3
heterostructures (HSs). The quenching of the WSe2 emission is apparent
in the WSe2/CrCl3 HSs due to an efficient charge transfer process
enabled by the relative band alignment within the structures. Moreover,
we demonstrate that at specific spatial locations in the structures, the
magnetic proximity effect between the WSe2 ML and the CrCl3 bulk
activates dark exciton emission within the WSe2 ML. The dark exciton
emission in the WSe2 ML survives to a higher temperature than the
intraplane Curie temperature (TC) of the CrCl3 because of its elevated
TC in the strained regions of the CrCl3 layer. Our findings are relevant
to the development of spintronics and valleytronics with long-lived dark
states on technological timescales, as well as to sensing applications
of local magnetic fields realized simultaneously in multiple dimensions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{WOS:001407856300001,
title = {Single photon sources and single electron transistors in two-dimensional
materials},
author = {D Litvinov and A Wu and M Barbosa and K Vaklinova and M Grzeszczyk and G Baldi and M Zhu and M Koperski},
doi = {10.1016/j.mser.2025.100928},
times_cited = {9},
issn = {0927-796X},
year = {2025},
date = {2025-04-01},
journal = {MATERIALS SCIENCE & ENGINEERING R-REPORTS},
volume = {163},
publisher = {ELSEVIER SCIENCE SA},
address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND},
abstract = {The future optoelectronic technologies may operate on the basis of
individual elementary particles, including photons and electrons.
Achieving control knobs at such a fundamental level necessitates
substantial progress in the domains of materials and device engineering.
Recently, two-dimensional (2D) materials have become an important
platform for such investigations, as their layered crystal structures
give rise to inherent in-plane confinement of electrons. Defect
engineering and/or van der Waals heterostructure device fabrication
provide multiple strategies to induce further lateral confinement,
leading to discrete electronic states required for both single photon
emission and single electron operation. Herewith, we review the
cutting-edge developments regarding single photon sources and single
electron transistors in 2D materials. We provide a perspective on the
convergence of these two separate fields into single electron-photon
device platforms enabled by the unique characteristics of 2D systems.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}