探究 MoS2 晶体中金属到半导体结构相变的动力学。
Probing the Dynamics of the Metallic-to-Semiconducting Structural Phase Transformation in MoS2 Crystals.
机构信息
†Department of Chemistry and ‡Department of Physics, Columbia University, New York, New York 10027, United States.
§Mining and Materials Engineering, McGill University, Montreal, QC H3A 0C5, Canada.
出版信息
Nano Lett. 2015 Aug 12;15(8):5081-8. doi: 10.1021/acs.nanolett.5b01196. Epub 2015 Jul 7.
We have investigated the phase transformation of bulk MoS2 crystals from the metastable metallic 1T/1T' phase to the thermodynamically stable semiconducting 2H phase. The metastable 1T/1T' 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 ± 60 meV (38 ± 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' to 2H in a single laser pass. The mechanisms for the phase transformation are discussed.
我们研究了块状 MoS2 晶体从亚稳的金属 1T/1T'相到热力学稳定的半导体 2H 相的相变。亚稳的 1T/1T'材料是通过锂插层和脱插层制备的。通过原位拉曼和光学反射光谱研究了相变的热驱动动力学，得到的激活能为 400 ± 60 meV（38 ± 6 kJ/mol）。我们使用 DFT 方法计算了这些转变的预期最小能量途径。实验激活能大致对应于单个分子式单元的理论势垒，表明相变的成核相当局部。我们还报告说，飞秒激光写入可以在单个激光脉冲中将 1T/1T'转换为 2H。讨论了相变的机制。
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