Direct Bandgap-like Strong Photoluminescence from Twisted Multilayer MoS<sub>2</sub> Grown on SrTiO<sub>3</sub>.
basic_science · Level V
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- Record sourced from PubMed, PMID 33284605.
- Also identified by DOI 10.1021/acsnano.0c04801.
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Abstract
While direct bandgap monolayer 2D transition metal dichalcogenides (TMDs) have emerged as an important optoelectronic material due to strong light-matter interactions, their multilayer counterparts exhibit an indirect bandgap resulting in poor photon emission quantum yield. We report strong direct bandgap-like photoluminescence at ∼1.9 eV from multilayer MoS<sub>2</sub> grown on SrTiO<sub>3</sub>, whose intensity is significantly higher than that observed in multilayer MoS<sub>2</sub>/SiO<sub>2</sub>. Using high-resolution electron microscopy we observe interlayer twist and >8% increase in the van der Waals gap, which leads to weaker interlayer coupling. This affects the evolution of the band structure in multilayer MoS<sub>2</sub> as probed by transient absorption spectroscopy, causing higher photo carrier recombination at the direct gap. Our results provide a platform that could enable multilayer TMDs for robust optical device applications.