Centimeter-Scale, Large-Area, Few-Layer 1T'-WTe2 Films by Chemical Vapor Deposition and Its Long-Term Stability in Ambient Condition
Centimeter-Scale, Large-Area, Few-Layer 1T'-WTe2 Films by Chemical Vapor Deposition and Its Long-Term Stability in Ambient Condition
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DOI：
10.1021/acs.jpcc.8b00679
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发表时间：
2018
影响因子：
3.7
通讯作者：
Chang Haixin
中科院分区：
文献类型：
--
作者：
Li Jie;Cheng Shuai;Liu Zhixuan;Zhang Wenfeng;Chang Haixin
WTe 2具有不同于硫化物和硒化物的独特性质。大面积、均匀的少层1 T ′相WTe 2和长期稳定性是WTe 2基础研究和应用的关键。本文首次采用低温化学气相沉积（CVD）方法制备了厘米级、大面积、均匀的多层1 T ′-WTe 2薄膜，并研究了这种CVD生长的1 T ′-WTe 2薄膜在室温条件下长达30天的长期稳定性。拉曼光谱和透射电子显微镜揭示了高品质的WTe 2。少层WTe 2的厚度可以很好地调节，并观察到厚度依赖的拉曼光谱。发现在环境条件下，不同暴露时间的空气暴露对电和量子电子输运性质有很大影响。电导率随暴露降低约10倍，而在原始样品和暴露于空气中30天的样品中观察到弱的反定位行为。意外地发现表面氧化诱导的磁电阻增强高达30%。
WTe2shows unique properties different from sulfides and selenides. Large-area, uniform few-layer 1T′ phase WTe2and long-term stability are essential for fundamental studies and applications of WTe2. Here, centimeter-scale, large-area, uniform few-layer 1T′-WTe2films are prepared by a facile, low-temperature, chemical vapor deposition (CVD) method and the long-term stability of such CVD-grown 1T′-WTe2up to 30 days in ambient condition is studied for the first time. Raman spectroscopy and transmission electron microscopy reveal the high quality of WTe2. The thickness of few-layer WTe2can be well tuned, and thickness-dependent Raman spectra are observed. The electrical and quantum electronic transport properties are found to be highly influenced by air exposure with different exposure times under ambient condition. The conductivity decreases by about 10 times with exposure, whereas weak antilocation behavior is observed in both pristine and air-exposed samples for 30 days. Surface-oxidization-induced magnetoresistance enhancement up to 30% is discovered unexpectedly.