Defect-Induced Vibration Modes of Ar+-Irradiated MoS2
Defect-Induced Vibration Modes of Ar+-Irradiated MoS2
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DOI：
10.1103/physrevapplied.7.024001
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发表时间：
2017-02-06
影响因子：
4.6
通讯作者：
Ohno, Koichi
中科院分区：
文献类型：
--
作者：
Bae, Soungmin;Sugiyama, Natsuki;Ohno, Koichi
利用拉曼光谱和第一性原理计算研究了Ar+辐照的二硫化钼（MoS 2）表面。实验研究表明，Ar+辐照在MoS 2的拉曼活性E-2g（1）和A（1g）模的低频侧产生卫星峰，并在450 cm（-1）附近产生新峰。我们从第一性原理出发计算了缺陷MoS 2体系的声子模和拉曼谱，发现Mo和S空位引起了这种卫星峰.这些卫星峰是E-2g（1）和A（1g）模式的调制，用振动模式的局部化和散射来描述。然而，在450 cm（-1）处的新峰是S空位的独特特征。在低辐照剂量下，S空位是主要缺陷，而对于大辐照剂量，卫星峰遮蔽了MoS 2峰，这对于Mo空位和MoS 6空位簇是典型的。因此，我们表明，拉曼光谱不仅可以用来观察二维材料中的缺陷，而且可以识别的缺陷的类型。
The Ar+-irradiated molybdenum-disulfide (MoS2) surface is studied by means of Raman spectroscopy and first-principles calculation. This experimental study reveals that Ar+ irradiation gives rise to satellite peaks at the lower-frequency side of the Raman-active E-2g(1) and A(1g) modes of MoS2 and a new peak at approximately 450 cm(-1). We calculate the phonon modes and Raman spectra of defective MoS2 systems from first principles, and show that Mo and S vacancies give rise to such satellite peaks. These satellite peaks are a modulation of the E-2g(1) and A(1g) modes, described in terms of localization and scattering of vibration modes. The new peak at 450 cm(-1), however, is a unique signature of the S vacancy. At low irradiation doses, the S vacancy is the dominant defect, whereas for large irradiation doses, the satellite peaks overshadow the MoS2 peaks, which we show to be typical for the Mo vacancy and MoS6 vacancy cluster. We thus show that Raman spectroscopy can be used not only to observe defects in two-dimensional materials, but also to identify the type of the defects.