Enhanced Trion Emission in Monolayer MoSe2 by Constructing a Type-I Van Der Waals Heterostructure

Funding Information: J.M.D. thanks China Scholarship Council (File no. 201706890037). L.H. thanks the National Natural Science Foundation of China (project number 61804098) and the Zhejiang Provincial Natural Science Foundation of China (project number LZ21E020002). Y.J.Z. thanks the Shenzhen Science and Technology Project under Grant no. JCYJ20180507182246321. A.V.K. also thanks the DFG for support within the projects KR 4866/2‐1 (project number 339 406129719). The computational support from the Technical University of Dresden computing cluster (TAURUS) and from High Performance Computing Center (HLRS) in Stuttgart, Germany is gratefully appreciated. The authors thank Scheumann for the metal deposition of the substrates. The nanofabrication facilities (NanoFaRo) at the Ion Beam Center at the HZDR are also gratefully acknowledged. Publisher Copyright: © 2021 The Authors. Advanced Functional Materials published by Wiley-VCH GmbHTrions, quasi-particles consisting of two electrons combined with one hole or of two holes with one electron, have recently been observed in transition metal dichalcogenides (TMDCs) and drawn increasing attention due to potential applications of these materials in light-emitting diodes, valleytronic devices as well as for being a testbed for understanding many-body phenomena. Therefore, it is important to enhance the trion emission and its stability. In this study, a MoSe2/FePS3 van der Waals heterostructure (vdWH) with type-I band alignment is constructed, which allows for carriers injection from FePS3 to MoSe2. At low temperatures, the neutral exciton (X0) emission in this vdWH is almost completely suppressed. The ITrion/Ix0 intensity ratio increases from 0.44 in a single MoSe2 monolayer to 20 in this heterostructure with the trion charging state changing from negative in the monolayer to positive in the heterostructure. The optical pumping with circularly polarized light shows a 14% polarization for the trion emission in MoSe2/FePS3. Moreover, forming such type-I vdWH also gives rise to a 20-fold enhancement of the room temperature photoluminescence from monolayer MoSe2. These results demonstrate a novel approach to convert excitons to trions in monolayer 2D TMDCs via interlayer doping effect using type-I band alignment in vdWH.Peer reviewe