Raman Spectra of Monolayer, Few-Layer, and Bulk ReSe2: An Anisotropic Layered Semiconductor
Raman Spectra of Monolayer, Few-Layer, and Bulk ReSe2: An Anisotropic Layered Semiconductor
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DOI：
10.1021/nn5053926
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发表时间：
2014-11-01
期刊：
影响因子：
17.1
通讯作者：
Bending, Simon J.
中科院分区：
文献类型：
--
作者：
Wolverson, Daniel;Crampin, Simon;Bending, Simon J.
二硒化铼（ReSe 2）是一种层状间接带隙半导体，其微机械分裂可以产生由一个平面的硒原子组成的单层，上面和下面有硒原子。ReSe 2在过渡金属二硫属化物中是不寻常的，因为它具有低对称性;它是三斜晶系，每个晶胞有四个分子式单元，并且具有在bar上的空间群P（1）。拉曼散射在单层，几层，和散装ReSe 2的实验研究表明，丰富的光谱组成的18个预期的线与良好的信号强度，明显的面内各向异性的强度，并没有证据表明样品在典型的测量过程中的降解。观察到层厚度下降到一个单层的拉曼带的频率没有变化，但是带的相对强度的显著变化允许确定晶体取向和单层区域。支持的理论包括计算的电子能带结构和布里渊区中心声子模式的散装和单层ReSe 2以及确定每个模式的散射强度的拉曼张量。据发现，对于其他过渡金属dichalcogenides，拉曼散射提供了一个强大的诊断工具，用于研究层的厚度，也在几层ReSe 2层取向。
Rhenium diselenide (ReSe2) is a layered indirect gap semiconductor for which micromechanical cleavage can produce monolayers consisting of a plane of rhenium atoms with selenium atoms above and below. ReSe2 is unusual among the transition-metal dichalcogenides in having a low symmetry; it is triclinic, with four formula units per unit cell, and has the bulk space group P (1) over bar. Experimental studies of Raman scattering in monolayer, few-layer, and bulk ReSe2 show a rich spectrum consisting of up to 16 of the 18 expected lines with good signal strength, pronounced in-plane anisotropy of the intensities, and no evidence of degradation of the sample during typical measurements. No changes in the frequencies of the Raman bands with layer thickness down to one monolayer are observed, but significant changes in relative intensity of the bands allow the determination of crystal orientation and of monolayer regions. Supporting theory includes calculations of the electronic band structure and Brillouin zone center phonon modes of bulk and monolayer ReSe2 as well as the Raman tensors determining the scattering intensity of each mode. It is found that, as for other transition-metal dichalcogenides, Raman scattering provides a powerful diagnostic tool for studying layer thickness and also layer orientation in few-layer ReSe2.