scholarly journals Giant Photoluminescence Enhancement and Carrier Dynamics in MoS2 Bilayers with Anomalous Interlayer Coupling

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1994
Author(s):  
Han Li ◽  
Yating Ma ◽  
Zhongjie Xu ◽  
Xiang’ai Cheng ◽  
Tian Jiang
Keyword(s):  
Optical Properties ◽  
Transition Metal Dichalcogenides ◽  
Interlayer Coupling ◽  
Carrier Dynamics ◽  
Probe Signal ◽  
Exciton Resonance ◽  
Pump Probe ◽  
Metal Dichalcogenides ◽  
Photoluminescence Enhancement ◽  
Probe Measurements

Fundamental researches and explorations based on transition metal dichalcogenides (TMDCs) mainly focus on their monolayer counterparts, where optical densities are limited owing to the atomic monolayer thickness. Photoluminescence (PL) yield in bilayer TMDCs is much suppressed owing to indirect-bandgap properties. Here, optical properties are explored in artificially twisted bilayers of molybdenum disulfide (MoS2). Anomalous interlayer coupling and resultant giant PL enhancement are firstly observed in MoS2 bilayers, related to the suspension of the top layer material and independent of twisted angle. Moreover, carrier dynamics in MoS2 bilayers with anomalous interlayer coupling are revealed with pump-probe measurements, and the secondary rising behavior in pump-probe signal of B-exciton resonance, originating from valley depolarization of A-exciton, is firstly reported and discussed in this work. These results lay the groundwork for future advancement and applications beyond TMDCs monolayers.

scholarly journals Valley depolarization in downconversion and upconversion emission of monolayer WS2 at room temperature

Nanophotonics ◽  
2020 ◽  
Vol 9 (16) ◽  
pp. 4809-4818
Author(s):  
Han Li ◽  
Yating Ma ◽  
Yizhen Sui ◽  
Yuxiang Tang ◽  
Ke Wei ◽  
...  
Keyword(s):  
Transition Metal ◽  
Room Temperature ◽  
Transition Metal Dichalcogenides ◽  
Upconversion Emission ◽  
Pump Probe ◽  
Saturated Absorption ◽  
Metal Dichalcogenides ◽  
Exciton Interactions ◽  
Anti Stokes ◽  
Probe Measurements

AbstractBenefiting from strong photon–exciton and phonon–exciton interactions in atomic thickness, transition metal dichalcogenides (TMDCs) are viewed as one promising platform for exploring elementary excitonic photoluminescence (PL) and intrinsic spin–valley properties at the monolayer limit. Despite well-studied Stokes downconversion (DC) PL, the anti-Stokes upconversion (UC) PL has been recently reported in TMDC monolayers, which mainly focus on UC mechanisms while detailed valley-related dynamical processes are unwittingly less concerned. Here, we carry out an in-depth investigation on both DC and UC emission features of monolayer WS2 at room temperature, where UC PL persists with energy gain up to 190 meV. The PL excitation and power-dependent experiments clearly distinguish the origins of DC PL and UC PL, which refer to saturated absorption and phonon-assisted transition from charged trions to neutral A-excitons. And contrast valley properties are observed in DC and UC scenarios with polarization-resolved PL and pump–probe measurements. According to the experimental facts, phenomenological dynamical DC and UC scenarios are modeled with intervalley depolarization taken into consideration, in which intermediates from spontaneous intervalley depolarization account for the observed emission and valley properties. This work can help understand the light–matter interactions and valley properties in monolayer TMDCs.

Synergistic vacancy defects and mechanical strain for the modulation of the mechanical, electronic and optical properties of monolayer tungsten disulfide

2021 ◽  
Vol 23 (10) ◽  
pp. 6298-6308
Author(s):  
Chan Gao ◽  
Xiaoyong Yang ◽  
Ming Jiang ◽  
Lixin Chen ◽  
Zhiwen Chen ◽  
...  
Keyword(s):  
Optical Properties ◽  
Transition Metal ◽  
Mechanical Strain ◽  
Transition Metal Dichalcogenides ◽  
Strain Engineering ◽  
Tungsten Disulfide ◽  
Defect Engineering ◽  
Vacancy Defects ◽  
Electronic And Optical Properties ◽  
Metal Dichalcogenides

The combination of defect engineering and strain engineering for the modulation of the mechanical, electronic and optical properties of monolayer transition metal dichalcogenides (TMDs).

Wrinkle and Near Resonance Effect on the Vibrational and Electronic properties in Compressed Monolayer MoSe2

2021 ◽  
Author(s):  
Yan Liu ◽  
Qiang Zhou ◽  
Yalan Yan ◽  
Liang Li ◽  
Jian Zhu ◽  
...  
Keyword(s):  
High Pressure ◽  
Optical Properties ◽  
Transition Metal ◽  
Electronic Properties ◽  
Resonance Effect ◽  
Transition Metal Dichalcogenides ◽  
Effective Technique ◽  
Near Resonance ◽  
Metal Dichalcogenides

Pressure has been considered as an effective technique to modulate the structural, electronic, and optical properties of transition metal dichalcogenides (TMDs) materials. Here, by performing in situ high pressure Raman,...

Intriguing electronic structures and optical properties of two-dimensional van der Waals heterostructures of Zr2CT2 (T = O, F) with MoSe2 and WSe2

2018 ◽  
Vol 6 (11) ◽  
pp. 2830-2839 ◽  
Author(s):  
Gul Rehman ◽  
S. A. Khan ◽  
B. Amin ◽  
Iftikhar Ahmad ◽  
Li-Yong Gan ◽  
...  
Keyword(s):  
Optical Properties ◽  
Material Properties ◽  
First Principles ◽  
Electronic Structures ◽  
Van Der Waals ◽  
Transition Metal Dichalcogenides ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Van Der Waals Heterostructures ◽  
Metal Dichalcogenides

Based on (hybrid) first-principles calculations, material properties (structural, electronic, vibrational, optical, and photocatalytic) of van der Waals heterostructures and their corresponding monolayers (transition metal dichalcogenides and MXenes) are investigated.

scholarly journals Tailored performance of layered transition metal dichalcogenides via integration with low dimensional nanostructures

RSC Advances ◽  
2017 ◽  
Vol 7 (20) ◽  
pp. 11987-11997 ◽  
Author(s):  
De-Sheng Liu ◽  
Jiang Wu ◽  
Yanan Wang ◽  
Haining Ji ◽  
Lei Gao ◽  
...  
Keyword(s):  
Optical Properties ◽  
Transition Metal ◽  
Sandwich Structure ◽  
Transition Metal Dichalcogenides ◽  
Electrical And Optical Properties ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal ◽  
Low Dimensional

Transition metal dichalcogenides (TMDs) with a unique sandwich structure have attracted tremendous attention in recent years due to their distinctive electrical and optical properties.

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