Shape-control growth of 2D-In2Se3 with out-of-plane ferroelectricity by chemical vapor deposition

Rashad Rashid; Francis Chi-Chung Ling; Shuang-Peng Wang; Ke Xiao; Xiaodong Cui; T. H. Chan; H. C. Ong; Waqar Azeem; Muhammad Younas

doi:10.1039/C9NR10207H

Shape-control growth of 2D-In₂Se₃ with out-of-plane ferroelectricity by chemical vapor deposition†

Rashad Rashid,

*^ab Francis Chi-Chung Ling,

*^a Shuang-Peng Wang,

^c Ke Xiao,^a Xiaodong Cui,^a T. H. Chan,^d H. C. Ong,^d Waqar Azeem^a and Muhammad Younas

Author affiliations

* Corresponding authors

^a Department of Physics, The University of Hong Kong, Pokfulam Road, China
E-mail: rashad0725@gmail.com

^b National Institute of Lasers and Optronics (NILOP), Islamabad, Pakistan

^c Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macao S.A.R., China

^d Department of Physics, The Chinese University of Hong Kong, Sha Tin, Hong Kong

^e PCG, Physics Division, PINSTECH, P.O. Nilore, Islamabad 45650, Pakistan

Abstract

For potential applications in ferroelectric switching and piezoelectric nano-generator devices, the promising ferroelectric properties of two dimensional (2D) layered In₂Se₃ attracted much attention. In the present study, 2D In₂Se₃ flakes down to monolayers are grown by the chemical vapor deposition (CVD) technique on a mica substrate with their structural, optical and ferroelectric properties being studied. The effect of growth parameters (time of growth and Ar flow rate) on the shape and size of the deposited flakes was studied. The optical microscopy study revealed that the flake changed from a circular shape to a sharp face triangle as the Ar flow rate and growth time increased. Raman spectroscopy and high-resolution scanning transmission electron microscopy (HR-STEM) studies revealed that the flakes were of α and β phases, each of which has a hexagonal crystal structure. Strong second harmonic generation (SHG) was observed from α-In₂Se₃, demonstrating its non-centrosymmetric structure. The piezo-force microscopic (PFM) study showed the presence of out of plane (OOP) ferroelectricity with no in plane (IP) ferroelectricity in CVD grown α-In₂Se₃ indicating its vertically confined piezoresponse, which was tuned by the applied electric bias and the flake thickness. The present result of shape-controlled growth of In₂Se₃ with OOP ferroelectricity would open new pathways in the field of 2D ferroelectric switching devices.

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Article information

DOI: https://doi.org/10.1039/C9NR10207H
Article type: Paper
Submitted: 02 Dec 2019
Accepted: 29 Jun 2020
First published: 30 Jun 2020

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Nanoscale, 2020,12, 20189-20201

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Shape-control growth of 2D-In₂Se₃ with out-of-plane ferroelectricity by chemical vapor deposition

R. Rashid, F. C. Ling, S. Wang, K. Xiao, X. Cui, T. H. Chan, H. C. Ong, W. Azeem and M. Younas, Nanoscale, 2020, 12, 20189 DOI: 10.1039/C9NR10207H

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