WS2/WSe2异质结层间相互作用的光谱研究

An optical spectrum study of interlayer interaction in WS2/WSe2 heterostructure

原子级厚度的过渡金属硫化物二维材料具有独特的电子和光学性质,当将其构筑成原子层异质结时,由于层间耦合作用和界面电荷传递,导致产生新的光学性质,在光电器件方面具有重要的潜在应用.利用机械剥离法制备了WS 2/WSe 2异质结,通过变温拉曼光谱和变温光致发光光谱,研究了异质结中的层间相互作用和界面电荷传递.从拉曼光谱和光致发光光谱上观测到了层间声子和层间激子的存在,表明WS 2和WSe 2构成的异质结中存在明显的层间相互作用.由于WS 2和WSe 2形成II型能带排列,电子从WSe 2向WS 2转移,显著影响带电激子和中性激子发光强度.

Atomic-scale two-dimentional transition metal dichalcogenides possess novel electronic and optical properties.Stacking them into van der Waals heterostructures generates new optical properties because of interlayer coupling and charge transfer at the interface,which has important potential applications in photoelectric devices.WS 2/WSe 2 heterostructure was fabricated successfully by mechanical exfoliation and the interlayer interaction was studied by temperature-dpendent Raman spectra and photoluminescence(PL)spectra.Interlayer phonon mode and exciton were observed from Raman spectra and PL spectra respectively indicating that WS2/WSe2 heterostructure had obvious interaction between layers.Because of type II band alignment at the interface of WS2/WSe2 heterostructure,electrons were transferred from WSe2 to WS2 thus significantly affecting the PL intenstiy of trions and excitons.