Fabrication-Dependent Interfacial Charge Transfer in SnS/WSe2 van der Waals Heterostructures

초록

Two-dimensional (2D) van der Waals (vdW) heterostructures offer significant potential in optoelectronics by integrating distinct materials without lattice mismatch. The formation of clean, well-defined interfaces within these heterostructures is critical for optimizing their performance. In this study, we investigate the interface properties of vdW heterostructures composed of tin sulfide (SnS) and tungsten diselenide (WSe2), depending on fabrication methods. Our comparative study involves: 1) the direct epitaxy of SnS crystals on WSe2 flakes via a two-step growth process, and 2) the PMMA-assisted transfer of as-grown SnS onto WSe2. We find that direct epitaxy results in better interfacial contact compared to the transfer approach, leading to enhanced efficiency of interlayer exciton formation due to improved charge transfer at the type II SnS/WSe2 heterojunction. Our findings contribute to the precise engineering of band alignment and optoelectronic properties, demonstrating the significant potential of vdW heterostructures for advanced semiconductor applications.