A Simple Method for Synthesis of High-Quality Millimeter-Scale 1T' Transition-Metal Telluride and Near-Field Nanooptical Properties

Kun Chen; Zefeng Chen; Xi Wan; Zebo Zheng; Fangyan Xie; Wenjun Chen; Xuchun Gui; Huanjun Chen; Weiguang Xie; Jianbin Xu

doi:10.1002/adma.201700704

A Simple Method for Synthesis of High-Quality Millimeter-Scale 1T' Transition-Metal Telluride and Near-Field Nanooptical Properties

Adv Mater. 2017 Oct;29(38). doi: 10.1002/adma.201700704. Epub 2017 Aug 21.

Authors

Kun Chen¹, Zefeng Chen¹, Xi Wan², Zebo Zheng³, Fangyan Xie⁴, Wenjun Chen⁵, Xuchun Gui⁵, Huanjun Chen³, Weiguang Xie⁶, Jianbin Xu¹

Affiliations

¹ Department of Electronic Engineering and Materials Science and Technology Research Center, The Chinese University of Hong Kong, Hong Kong SAR, 999077, P. R. China.
² Engineering Research Center of IoT Technology Applications (Ministry of Education), Department of Electronic Engineering, Jiangnan University, Wuxi, 214122, P. R. China.
³ State Key Lab of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, 510275, P. R. China.
⁴ Instrumental Analysis and Research Center, Sun Yat-sen University, Guangzhou, 510275, P. R. China.
⁵ State Key Lab of Optoelectronic Materials and Technologies, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, 510275, P. R. China.
⁶ Siyuan Laboratory, Department of Physics, Jinan University, Guangzhou, Guangdong, 510632, China.

PMID: 28833622
DOI: 10.1002/adma.201700704

Abstract

The controlled synthesis of MoTe₂ and WTe₂ is crucial for their fundamental research and potential electronic applications. Here, a simplified ambient-pressure chemical vapor deposition (CVD) strategy is developed to synthesize high-quality and large-scale monolayer and few-layer 1T'-phase MoTe₂ (length ≈ 1 mm) and WTe₂ (length ≈ 350 µm) crystals by using ordinary salts (KCl or NaCl) as the growth promoter combining with low-cost (NH₄ )₆ Mo₇ O₂₄ ·4H₂ O and hydrate (NH₄ )₁₀ W₁₂ O₄₁ ·xH₂ O as the Mo and W sources, respectively. Atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and transmission electron microscopy confirm the high-quality nature and the atomic structure of the as-grown 1T' MoTe₂ and WTe₂ flakes. Variable-temperature transport measurements exhibit their semimetal properties. Furthermore, near-field nanooptical imaging studies are performed on the 1T' MoTe₂ and WTe₂ flakes for the first time. The sub-wavelength effects of 1T'-phase MoTe₂ (λ_p ≈ 140 nm) and WTe₂ (λ_p ≈ 100 nm) are obtained. This approach paves the way for the growth of special transition-metal dichalcogenides materials and boosts the future polaritonic research of 2D telluride compounds.

Keywords: 1T′ MoTe2; 1T′ WTe2; APCVD; ordinary salt promoters; sub-wavelength effect.