Department of Physics and Astronomy, The University of Kansas, Lawrence, KS, 66045, USA.
Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing, 100044, China.
Small. 2015 Nov 4;11(41):5565-71. doi: 10.1002/smll.201501668. Epub 2015 Aug 28.
Anisotropic optical and transport properties of monolayer ReS2 fabricated by mechanical exfoliation are reported. Transient absorption measurements with different polarization configurations and sample orientations reveal that the absorption coefficient and transient absorption are both anisotropic, with maximal and minimal values occurring when the light polarization is parallel and perpendicular to the Re atomic chains, respectively. The maximal values are about a factor of 2.5 of the minimal values. By resolving the spatiotemporal dynamics of excitons, it is found that the diffusion coefficient of excitons moving along Re atomic chains is about 16 cm(2) s(-1) at room temperature, which is about a factor of three larger than those moving perpendicular to that direction. An exciton lifetime of 40 ps is also extracted. These findings establish monolayer ReS2 as an anisotropic 2D transition metal dichalcogenide.
本文报道了通过机械剥离法制备的单层 ReS2 的各向异性光学和输运性质。通过不同偏振配置和样品取向的瞬态吸收测量发现，吸收系数和瞬态吸收均具有各向异性，当光偏振平行和垂直于 Re 原子链时，分别出现最大值和最小值。最大值约为最小值的 2.5 倍。通过解析激子的时空动力学，发现室温下沿 Re 原子链运动的激子的扩散系数约为 16 cm(2) s(-1)，约比垂直于该方向运动的激子大 3 倍。还提取了激子寿命为 40 ps。这些发现确立了单层 ReS2 作为各向异性二维过渡金属二卤化物。
