Premium
Phase‐Tunable Synthesis of Ultrathin Layered Tetragonal CoSe and Nonlayered Hexagonal CoSe Nanoplates
Author(s) -
Ma Huifang,
Wan Zhong,
Li Jia,
Wu Ruixia,
Zhang Zhengwei,
Li Bo,
Zhao Bei,
Qian Qi,
Liu Yuan,
Xia Qinglin,
Guo Guanghua,
Duan Xidong,
Duan Xiangfeng
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201900901
Subject(s) - tetragonal crystal system , materials science , selected area diffraction , magnetoresistance , chemical vapor deposition , nanotechnology , phase (matter) , electron diffraction , electrical resistivity and conductivity , nanostructure , diffraction , transmission electron microscopy , condensed matter physics , optics , chemistry , physics , electrical engineering , organic chemistry , engineering , quantum mechanics , magnetic field
Abstract Multiple structural phases in transition metal dichalcogenides have attracted considerable recent interest for their tunable chemical and electronic properties. Herein, a chemical vapor deposition route to ultrathin CoSe nanoplates with tunable structure phases is reported. By precisely tailoring the growth temperature, ultrathin 2D layered tetragonal CoSe nanoplates and nonlayered hexagonal CoSe nanoplates can be selectively prepared as square or hexagonal geometries, with thickness as thin as 2.3 and 3.7 nm, respectively. X‐ray diffraction, transmission electron microscopy, and selected area electron diffraction studies show that both types of nanoplates are high‐quality single crystals. Electrical transport studies reveal that both the tetragonal and hexagonal CoSe nanoplates show strong thickness‐tunable electrical properties and excellent breakdown current density. The 2D hexagonal CoSe nanoplates display metallic behavior with an excellent conductivity up to 6.6 × 10 5 S m −1 and an extraordinary breakdown current density up to 3.9 × 10 7 A cm −2 , while the square tetragonal nanoplates show considerably lower conductivity up to 8.2 × 10 4 S m −1 with angle‐dependent magnetoresistance and weak antilocalization effect at lower field. This study offers a tunable material system for exploring multiphase 2D materials and their potential applications for electronic and magnetoelectronic devices.