Chemical Vapor Deposition Growth of Single Crystalline CoTe2 Nanosheets with Tunable Thickness and Electronic Properties
Chemical Vapor Deposition Growth of Single Crystalline CoTe2 Nanosheets with Tunable Thickness and Electronic Properties
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DOI：
10.1021/acs.chemmater.8b04069
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发表时间：
2018-12-25
影响因子：
8.6
通讯作者：
Duan, Xidong
中科院分区：
文献类型：
--
作者：
Ma, Huifang;Dang, Weiqi;Duan, Xidong
二维金属过渡金属二硫属化物（MTMD）在催化、电荷密度波（CDW）、互连、自旋力矩器件以及超导体等方面的基础研究和潜在应用越来越受到人们的关注。尽管有一些初步的努力，厚度可调的合成原子薄MTMD仍然是一个相当大的挑战。在这里，我们报告控制合成的二维碲化钴（CoTe 2）纳米片与可调厚度使用大气压化学气相沉积（APCVD）的方法，并研究其厚度依赖的电子性质。所得的纳米片显示出良好的多面六边形或三角形的几何形状与横向尺寸高达类似于200 μ m。在不同的生长温度或流速下的生长的系统研究表明，纳米片的厚度是很容易从超过30 nm到3.1 nm可调。X射线衍射（XRD）、透射电子显微镜（TEM）和高分辨率扫描透射电子显微镜（STEM）研究表明，所获得的CoTe 2纳米片是六方IT相的高质量单晶。电输运研究表明，二维CoTe 2纳米片显示出高达4.0 × 10（5）S m（-1）的优异电导率和高达2.1 × 10（7）A/cm（2）的非常高的击穿电流密度，两者都具有很强的厚度可调性。
Two-dimensional (2D) metallic transition metal dichalcogenides (MTMDs) have recently drawn increasing interest for fundamental studies and potential applications in catalysis, charge density wave (CDW), interconnections, spin torque devices, as well superconductors. Despite some initial efforts, the thickness-tunable synthesis of atomically thin MTMDs remains a considerable challenge. Here we report controlled synthesis of 2D cobalt telluride (CoTe2) nanosheets with tunable thickness using an atmospheric pressure chemical vapor deposition (APCVD) approach and investigate their thickness dependent electronic properties. The resulting nanosheets show a well-faceted hexagonal or triangular geometry with a lateral dimension up to similar to 200 mu m. Systematic studies of growth at varying growth temperatures or flow rates demonstrate that nanosheets thickness is readily tunable from over 30 nm down to 3.1 nm. X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution scanning transmission electron microscope (STEM) studies reveal the obtained CoTe2 nanosheets are high-quality single crystals in the hexagonal IT phase. Electrical transport studies show the 2D CoTe2 nanosheets display excellent electrical conductivities up to 4.0 x 10(5) S m(-1) and very high breakdown current densities up to 2.1 x 10(7) A/cm(2), both with strong thickness tunability.