Twist angle-dependent resonant tunneling electron transfer in WS₂/WSe₂/MoSe₂ heterostructures

Twisted van der Waals heterostructures formed by stacking monolayer materials offer a simple and exciting platform in condensed matter physics, where many novel physical effects have been observed. In the present work, a twist angle-dependent resonant tunneling electron transfer (RTET) effect, which was verified by giant quenching of WS₂ photoluminescence (PL), is found in the WS₂/WSe₂/MoSe₂ heterostructures (HS) by using PL measurements. Two types of interlayer excitons (IXs) are clearly observed, and the PL spectra measured under different excitations imply that charge transfer was a main contributor to the visibility of IXs. The samples with different stacking schemes are fabricated, and their PL spectra verified that the RTET from the conduction band of WS₂ to the conduction band of MoSe₂ is strongly dependent on the twist angle of WS₂/WSe₂/MoSe₂ HS. The band alignment of WS₂/WSe₂/MoSe₂ HS is calculated by using density functional theory (DFT) to support the RTET effect. Furthermore, the relationship between RTET and twist angles can be well-described by a quantum tunneling model. The efficiency of tunneling is actually related to momentum conservation in K-space. Our results provide additional insight into understanding the physics of IX and the process of charge transfer in twisted trilayer HS.