Structural and electronic signatures of stacking and intralayer transitions in epitaxial bilayer WSe2 on GaP(111)B
Abstract
Two-dimensional materials from the transition metal dichalcogenides family host multiple crystal phases and stacking configurations that strongly affect their electronic properties. Here, we investigate the structural and electronic phase evolution of epitaxial bilayer WSe2 grown by molecular beam epitaxy on Se-terminated GaP(111)B substrates. Films grown at low temperature (∼250 °C) exhibit a coexistence of rhombohedral 3R-stacked bilayers together with a minor crystal-phase heterostructure involving a 1T′ layer. In this configuration, the 1T′ phase is stabilized only as a monolayer stacked on top of a 1H layer (1T′/1H), while a fully stacked 1T′ bilayer is not observed. The GaP(111)B substrate likely plays an important role in stabilizing these metastable configurations through interface interactions and lattice registry effects. Post-growth annealing at 650 °C under selenium flux drives a complete transition toward the thermodynamically stable 2H stacking through a rearrangement of the interlayer registry. This transformation is evidenced by the disappearance of the electronic signatures of the 1T′ phase together with structural changes observed by diffraction and microscopy. Our results demonstrate that annealing provides an effective route to control stacking order and crystal phases in epitaxial WSe2 bilayers, opening new opportunities for phase engineering in two-dimensional materials.
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BibTeX
@article{bouaziz2026structural,
title = {{Structural and electronic signatures of stacking and intralayer transitions in epitaxial bilayer WSe2 on GaP(111)B}},
author = {Meryem Bouaziz and Samir El Masaoudi and Aymen Mahmoudi and Niels Chapuis and Mathieu Silly and Gilles Patriarche and Iann Gerber and Julien Chaste and Fabrice Oehler and Xavier Wallart and Abdelkarim Ouerghi},
journal = {Nanoscale},
year = {2026},
month = nov,
doi = {10.1039/d6nr01013j},
url = {https://hal.science/hal-05687513v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Structural and electronic signatures of stacking and intralayer transitions in epitaxial bilayer WSe2 on GaP(111)B
AU - Meryem Bouaziz
AU - Samir El Masaoudi
AU - Aymen Mahmoudi
AU - Niels Chapuis
AU - Mathieu Silly
AU - Gilles Patriarche
AU - Iann Gerber
AU - Julien Chaste
AU - Fabrice Oehler
AU - Xavier Wallart
AU - Abdelkarim Ouerghi
PY - 2026
DA - 2026/11/03
JO - Nanoscale
DO - 10.1039/d6nr01013j
UR - https://hal.science/hal-05687513v1
AB - Two-dimensional materials from the transition metal dichalcogenides family host multiple crystal phases and stacking configurations that strongly affect their electronic properties. Here, we investigate the structural and electronic phase evolution of epitaxial bilayer WSe2 grown by molecular beam epitaxy on Se-terminated GaP(111)B substrates. Films grown at low temperature (∼250 °C) exhibit a coexistence of rhombohedral 3R-stacked bilayers together with a minor crystal-phase heterostructure involving a 1T′ layer. In this configuration, the 1T′ phase is stabilized only as a monolayer stacked on top of a 1H layer (1T′/1H), while a fully stacked 1T′ bilayer is not observed. The GaP(111)B substrate likely plays an important role in stabilizing these metastable configurations through interface interactions and lattice registry effects. Post-growth annealing at 650 °C under selenium flux drives a complete transition toward the thermodynamically stable 2H stacking through a rearrangement of the interlayer registry. This transformation is evidenced by the disappearance of the electronic signatures of the 1T′ phase together with structural changes observed by diffraction and microscopy. Our results demonstrate that annealing provides an effective route to control stacking order and crystal phases in epitaxial WSe2 bilayers, opening new opportunities for phase engineering in two-dimensional materials.
SN - 2040-3364
SN - 2040-3372
ER -