Quasi-type-I band alignment in WS 2 /MoS 2 heterostructures produced by H 2 S-based CVD
Source abstract
Abstract
Abstract In this work we report the synthesis and characterization of WS 2 /MoS 2 heterostructures prepared by sequential chemical vapor deposition using H 2 S and thermally evaporated metal as precursors. A thin WS 2 covers (1–2 monolayers) are produced on pre-formed MoS 2 nanowall films, resulting in nearly complete quenching of the MoS 2 photoluminescence (PL) and emergence of a dominant WS 2 PL peak at higher energy. Remarkably, electrical measurements reveal that the thermally activated conduction in the both layered materials have nearly the same activation energies, suggesting comparable donor activation energies and a possible near-alignment of the CBM positions within experimental uncertainty. This particular ‘quasi-type-I’ alignment is in sharp contrast to the conventional staggered (type-II) alignment normally expected in WS 2 /MoS 2 heterostructures. Transient absorption pump–probe spectroscopy shows signatures consistent with ultrafast interlayer charge transfer and possible interlayer exciton formation. We present a comprehensive study of the optical, structural, and transport properties of prepared samples, and discuss the carrier transfer mechanisms that give rise to the observed PL redistribution.
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Research context
OpenAlex topics: 2D Materials and Applications · Chalcogenide Semiconductor Thin Films · Chemical and Physical Properties of Materials
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Affiliations
Lomonosov Moscow State University
Natural Science Center of GPI RAS
Moscow Center of Advanced Studies
Udmurt Federal Research Center of the Ural Branch of the Russian Academy of Sciences
Funding
Russian Science Foundation
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