Unconventional Enhancement of Photoluminescence in Multilayer MoS 2 within MoS 2 /MoO 2 Heterostructures: Implication for Optoelectronic Devices

作者：Hongrong Wu, Na Li, Maolin Tang, Wenhui Tang, Junhua Zhao · 发表于：ACS Applied Nano Materials · 年份：2023 · DOI：10.1021/acsanm.3c03445 · 被引用次数：7 · 研究领域：2D Materials and Applications、Plasmonic and Surface Plasmon Research、Advanced biosensing and bioanalysis techniques

Monolayer two-dimensional (2D) transition-metal chalcogenides (TMDs) with a direct bandgap are promising in future optoelectronics due to the strong light–matter interaction. Comparatively speaking, their multilayer counterparts show a higher carrier mobility and current capacity over the monolayer. However, multilayer TMDs with an indirect bandgap exhibit weak photoluminescence (PL) emission, hindering their practical applications. In this work, we discovered an unconventional PL enhancement of multilayer MoS 2 in chemical vapor-deposited MoS 2 /MoO 2 heterostructures, whose intensity is an order of magnitude higher than that observed in multilayer MoS 2 on SiO 2 /Si. The PL enhancement is mainly attributed to the surface plasmon resonance of MoO 2, as evidenced by UV–vis absorption spectroscopy of the MoS 2 /MoO 2 heterostructures and the laser wavelength selectivity of the PL enhancement. Meanwhile, a nanogap was observed at the interface of MoS 2 and MoO 2 by using high-resolution scanning transmission electron microscopy, which impedes the PL quenching induced by the charge transfer between multilayer MoS 2 and metallic MoO 2 . To confirm the mechanism, MoS 2 /BN/MoO 2 heterostructures were assembled by using insulating monolayer boron nitride (BN) to simulate the nanogap, and similar PL enhancement of multilayer MoS 2 was observed. To the best of our knowledge, surface plasmon resonance-enhanced PL emission by a metal oxide substrate has been rarely reported until now. ...