论文标题
双层MOS2中的超快电荷动力学和光致发光
Ultrafast charge dynamics and photoluminescence in bilayer MoS2
论文作者
论文摘要
我们对双层MOS2中超快电荷动力学和电子相互作用的相互作用的检查为理解发射光谱中的特征（两个峰）提供了微观基础。我们证明，虽然激发电荷的初始积累发生在二维Brillioun区域的Q点和附近，但发射主要通过两种途径进行：k点处的直接电荷重组和间接声子辅助的电子重组在k谷的k谷和Brillouin区域γ山的孔。分析电子量音相互作用的波矢量依赖性较高的能量峰将激发电子从Q到传导带中的K谷的声子辅助松弛。因此，我们的结果揭示了超快电荷动力学在理解几层过渡金属二核化合物的光电子特性中的重要性。这些计算基于密度矩阵公式中的时间依赖性密度功能理论。
Our examination of the interplay of ultrafast charge dynamics and electron-phonon interaction in bilayer MoS2 provides a microscopic basis for understanding the features (two peaks) in the emission spectrum. We demonstrate that while the initial accumulation of excited charge occurs at and near the Q point of the two-dimensional Brillioun zone, emission takes place predominantly through two pathways: direct charge recombination at the K point and indirect phonon-assisted recombination of electrons at the K valley and holes at Γ hill of the Brillouin zone. Analysis of the wave vector dependencies of the electron-phonon interaction traces the higher energy peak to phonon-assisted relaxation of the excited electrons from the Q to the K valley in the conduction band. Our results thus reveal the importance of ultrafast charge dynamics in understanding photoemissive properties of a few-layer transition-metal dichalcogenide. These calculations are based on time dependent density functional theory in the density matrix formulation.
