Probing the Dynamics of the Metallic-to-Semiconducting Structural Phase Transformation in MoS2 Crystals

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• 作者：Yinsheng Guo ; Dezheng Sun ; Bin Ouyang ; Archana Raja ; Jun Song ; Tony F. Heinz ; Louis E. Brus
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：August 12, 2015
• 年：2015
• 卷：15
• 期：8
• 页码：5081-5088
• 全文大小：403K
• ISSN：1530-6992

文摘

We have investigated the phase transformation of bulk MoS₂ crystals from the metastable metallic 1T/1T鈥?phase to the thermodynamically stable semiconducting 2H phase. The metastable 1T/1T鈥?material was prepared by Li intercalation and deintercalation. The thermally driven kinetics of the phase transformation were studied with in situ Raman and optical reflection spectroscopies and yield an activation energy of 400 卤 60 meV (38 卤 6 kJ/mol). We calculate the expected minimum energy pathways for these transformations using DFT methods. The experimental activation energy corresponds approximately to the theoretical barrier for a single formula unit, suggesting that nucleation of the phase transformation is quite local. We also report that femtosecond laser writing converts 1T/1T鈥?to 2H in a single laser pass. The mechanisms for the phase transformation are discussed.