title: Two-Dimensional SnS: A Phosphorene Analogue with Strong In-Plane Electronic Anisotropy.
abstract: We study the anisotropic electronic properties of two-dimensional (2D) SnS, an analogue of phosphorene, grown by physical vapor transport. With transmission electron microscopy and polarized Raman spectroscopy, we identify the zigzag and armchair directions of the as-grown 2D crystals. The 2D SnS field-effect transistors with a cross-Hall-bar structure are fabricated. They show heavily hole-doped (∼1019cm-3) conductivity with strong in-plane anisotropy. At room temperature, the mobility along the zigzag direction exceeds 20 cm2V-1s-1, which can be up to 1.7 times that in the armchair direction. This strong anisotropy is then explained by the effective mass ratio along the two directions and agrees well with previous theoretical predictions. Temperature-dependent carrier density determined the acceptor energy level to be ∼45 meV above the valence band maximum. This value matches a calculated defect level of 42 meV for Sn vacancies, indicating that Sn deficiency is the main cause of the p-type conductivity.
authors.affiliation: Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences , Shanghai 201800, China.|School of Physical Science and Technology, ShanghaiTech University , Shanghai 201210, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Tian
authors.affiliation: Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences , Shanghai 201800, China.|School of Physical Science and Technology, ShanghaiTech University , Shanghai 201210, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Chenglei
authors.initials: C
authors.lastname: Guo
authors.affiliation: School of Physical Science and Technology, ShanghaiTech University , Shanghai 201210, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Mingxing
authors.initials: M
authors.lastname: Zhao
authors.affiliation: School of Physical Science and Technology, ShanghaiTech University , Shanghai 201210, China.|University of Chinese Academy of Sciences , Beijing 100049, China.
authors.forename: Ranran
authors.initials: R
authors.lastname: Li
authors.affiliation: Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences , Shanghai 201800, China.|School of Physical Science and Technology, ShanghaiTech University , Shanghai 201210, China.|University of Chinese Academy of Sciences , Beijing 100049, China.|Center for Excellence in Superconducting Electronics (CENSE), Chinese Academy of Sciences , Shanghai 200050, China.
authors.forename: Jiamin
authors.identifier: 0000-0002-1892-1743
authors.initials: J
authors.lastname: Xue
keywords: 2D SnS; anisotropic electronic transport; field-effect transistor