CRYSTAL-ORIENTED WRINKLES WITH ORIGAMI-TYPE JUNCTIONS IN FEW-LAYER HBN
Camilla Karla Oliveira1,2, Egleidson F A Gomes1, Mariana C Prado1, Thonimar V Alencar1,
Regiane Nascimento1, Leandro M Malard1, Ronaldo J C Batista3, Alan B de Oliveira3, Hélio
Chacham1, Ana Maria de Paula1, Bernardo R A Neves1
1
Physics Department, Federal University of Minas Gerais, Belo Horizonte-MG, Brazil.
Physics Department, Federal University of Paraná, Curitiba-PR, Brazil.
3
Physics Department, Federal University of Ouro Preto, Ouro Preto-MG, Brazil.
Presenting author: Camilla Oliveira; [email protected]
2
We present an investigation of the morphology and optical response of annealed hexagonal
boron nitride (h-BN) few-layer flakes deposited on silicon oxide [1]. Atomic Force Microscopy
measurements show the formation of linear wrinkles along well-defined crystallographic
directions. These wrinkles form a network of threefold (mostly) and fourfold (rarely) origamitype junctions throughout the sample (figure 1). All threefold junctions and wrinkles are formed
along the armchair crystallographic direction, as independently confirmed by
octadecylphosphonic acid self-assembly investigation and polarization dependent Second
Harmonic Generation imaging. Furthermore, molecular dynamics simulations yield, through
spontaneous symmetry breaking, wrinkle junction morphologies that are consistent with both
the experiments and the proposed origami-folding model. Our findings indicate that this may
be a general property of several 2D materials under the proper stress-strain conditions with
direct consequences on device strain engineering.
Figure 1 - (a) A 10nm-thick flake showing an orientationally ordered wrinkle pattern. The
inset at the bottom left shows the FFT image of the flake topography. (b) Zoom-in AFM
image acquired at the region marked by a white square in (a). The wrinkle pattern orientation
is evidenced by the FFT image at the bottom left of the figure. (c) Detailed topographic
image of the wrinkle junction indicated by the white square in b. The color scale at the
bottom left of the image indicates its height variation.
References
1) Camilla Karla Oliveira, Egleidson F A Gomes, Mariana C Prado, Thonimar V Alencar,
Regiane Nascimento, Leandro M Malard, Ronaldo J C Batista, Alan B de Oliveira, Hélio
Chacham, Ana Maria de Paula, Bernardo R A Neves, “Crystal-oriented wrinkles with origamitype junctions in few-layer hexagonal boron nitride”. Nano Research (Print), 8 (2015) 1.