Direct Bandgap-like Strong Photoluminescence from Twisted Multilayer MoS2 Grown on SrTiO3
Soumya Sarkar Sinu Mathew Sandhya Chintalapati Ashutosh Rath Majid Panahandeh-Fard Surajit Saha Sreetosh Goswami Sherman Jun Rong Tan Kian Ping Loh Mary Scott
Sherman Jun Rong Tan
Mary Scott
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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 MoS2 grown on SrTiO3, whose intensity is significantly higher than that observed in multilayer MoS2/SiO2. 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 MoS2 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.
Keywords
2D materials, photoluminescence, interlayer twist, transition metal dichalcogenides, transition metal oxides
Source Title
ACS Nano
Publisher
American Chemical Society
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Date
2020-12-07
DOI
10.1021/acsnano.0c04801
Type
Article