Effect of lithium doping on the optical properties of monolayer MoS2
Effect of lithium doping on the optical properties of monolayer MoS2
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DOI：
10.1063/1.5021629
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发表时间：
2018-03
影响因子：
4
通讯作者：
Nihit Saigal;Isabelle Wielert;D. Čapeta;N. Vujičić;B. Senkovskiy;M. Hell;M. Kralj;A. Grüneis
中科院分区：
文献类型：
--
作者：
Nihit Saigal;Isabelle Wielert;D. Čapeta;N. Vujičić;B. Senkovskiy;M. Hell;M. Kralj;A. Grüneis
在低锂覆盖率（≤ 0.17单层）下，利用高真空（拉曼和圆偏振光致发光光谱研究了锂原子蒸发对生长在SiO2/Si衬底上的单层MoS 2表面的影响。随着Li掺杂的增加，MoS 2的主要E2 g 1和A1 g拉曼模式在能量上移动并加宽。此外，非带心声子模变得拉曼活动。这特别涉及双共振拉曼散射过程，涉及二硫化钼和缺陷的布里渊区的M和K点处的纵向声学声子模式。它还伴随着光致发光光谱的整体强度和圆偏振度的显著降低。在光学光谱中观察到的变化被理解为由锂原子和无序激活的电子和空穴的电子带结构的单层二硫化钼的谷间散射的电子掺杂的结果。
The effect of lithium atoms' evaporation on the surface of monolayer MoS2 grown on SiO2/Si substrate is studied using ultrahigh vacuum (∼10−11 mbar) Raman and circularly polarized photoluminescence spectroscopies, at low lithium coverage (up to ∼0.17 monolayer). With increasing Li doping, the dominant E2g1 and A1g Raman modes of MoS2 shift in energy and broaden. Additionally, non zone-center phonon modes become Raman active. This regards, in particular, to double resonance Raman scattering processes, involving longitudinal acoustic phonon modes at the M and K points of the Brillouin zone of MoS2 and defects. It is also accompanied by a significant decrease in the overall intensity and the degree of circular polarization of the photoluminescence spectrum. The observed changes in the optical spectra are understood as a result of electron doping by lithium atoms and disorder-activated intervalley scattering of electrons and holes in the electronic band structure of monolayer MoS2.