scholarly journals Strong Anisotropic Enhancement of Photoluminescence in WS2 Integrated With Plasmonic Nanowire Array

2020 ◽  
Author(s):  
Chunrui Han ◽  
Yu Wang ◽  
Weihu Zhou ◽  
Jianting Ye
Keyword(s):  
Nanowire Array ◽  
Transition Metal Dichalcogenides ◽  
Photonic Devices ◽  
Nanowire Arrays ◽  
Plasmonic Enhancement ◽  
Form Birefringence ◽  
Simultaneous Control ◽  
Wide Range ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal

Abstract Layered transition metal dichalcogenides (TMDCs) have shown great potential for a wide range of applications in photonics and optoelectronics. Nevertheless, valley decoherence severely randomizes its polarization which is important to a light emitter. Plasmonic metasurface with a unique way to manipulate the light-matter interaction may provide an effective and practical solution. Here by integrating TMDCs with plasmonic nanowire arrays, we demonstrate strong anisotropic enhancement of the excitonic emission at different spectral positions. For the indirect bandgap transition in bilayer WS2, multifold enhancement can be achieved with the PL polarization either perpendicular or parallel to the long axis of nanowires, which arises from the coupling of WS2 with localized or guided plasmon modes, respectively. Moreover, PL of a high linearity is obtained in the direct bandgap transition benefiting from, in addition to the plasmonic enhancement, the directional diffraction scattering of nanowire arrays. Our method with enhanced PL intensity contrasts to the conventional form-birefringence based on the aspect ratio of nanowire arrays where the intensity loss is remarkable. Our results provide a prototypical plasmon-exciton hybrid system for anisotropic enhancement of the PL at the nanoscale, enabling simultaneous control of intensity, polarization and wavelength toward practical ultrathin photonic devices based on TMDCs.

scholarly journals Strong anisotropic enhancement of photoluminescence in WS2 integrated with plasmonic nanowire array

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chunrui Han ◽  
Yu Wang ◽  
Weihu Zhou ◽  
Minpeng Liang ◽  
Jianting Ye
Keyword(s):  
Nanowire Array ◽  
Transition Metal Dichalcogenides ◽  
Photonic Devices ◽  
Nanowire Arrays ◽  
Plasmonic Enhancement ◽  
Form Birefringence ◽  
Simultaneous Control ◽  
Wide Range ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal

AbstractLayered transition metal dichalcogenides (TMDCs) have shown great potential for a wide range of applications in photonics and optoelectronics. Nevertheless, valley decoherence severely randomizes its polarization which is important to a light emitter. Plasmonic metasurface with a unique way to manipulate the light-matter interaction may provide an effective and practical solution. Here by integrating TMDCs with plasmonic nanowire arrays, we demonstrate strong anisotropic enhancement of the excitonic emission at different spectral positions. For the indirect bandgap transition in bilayer WS2, multifold enhancement can be achieved with the photoluminescence (PL) polarization either perpendicular or parallel to the long axis of nanowires, which arises from the coupling of WS2 with localized or guided plasmon modes, respectively. Moreover, PL of high linearity is obtained in the direct bandgap transition benefiting from, in addition to the plasmonic enhancement, the directional diffraction scattering of nanowire arrays. Our method with enhanced PL intensity contrasts to the conventional form-birefringence based on the aspect ratio of nanowire arrays where the intensity loss is remarkable. Our results provide a prototypical plasmon-exciton hybrid system for anisotropic enhancement of the PL at the nanoscale, enabling simultaneous control of the intensity, polarization and wavelength toward practical ultrathin photonic devices based on TMDCs.

scholarly journals Two-dimensional inorganic analogues of graphene: transition metal dichalcogenides

2016 ◽  
Vol 374 (2076) ◽  
pp. 20150318 ◽  
Author(s):  
Manoj K. Jana ◽  
C. N. R. Rao
Keyword(s):  
Transition Metal ◽  
Transition Metal Dichalcogenides ◽  
Single Layer ◽  
Layered Materials ◽  
Two Dimensional ◽  
2D Layered Materials ◽  
Wide Range ◽  
Buckminster Fullerene ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal

The discovery of graphene marks a major event in the physics and chemistry of materials. The amazing properties of this two-dimensional (2D) material have prompted research on other 2D layered materials, of which layered transition metal dichalcogenides (TMDCs) are important members. Single-layer and few-layer TMDCs have been synthesized and characterized. They possess a wide range of properties many of which have not been known hitherto. A typical example of such materials is MoS 2 . In this article, we briefly present various aspects of layered analogues of graphene as exemplified by TMDCs. The discussion includes not only synthesis and characterization, but also various properties and phenomena exhibited by the TMDCs. This article is part of the themed issue ‘Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene’.

scholarly journals Enhanced responsivity and detectivity of fast WSe2 phototransistor using electrostatically tunable in-plane lateral p-n homojunction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sayantan Ghosh ◽  
Abin Varghese ◽  
Kartikey Thakar ◽  
Sushovan Dhara ◽  
Saurabh Lodha
Keyword(s):  
Laser Power ◽  
High Performance ◽  
Flicker Noise ◽  
Transition Metal Dichalcogenides ◽  
Conducting Channel ◽  
Switching Speed ◽  
Wide Range ◽  
Metal Dichalcogenides ◽  
Added Benefit ◽  
Layered Transition Metal

AbstractLayered transition metal dichalcogenides have shown tremendous potential for photodetection due to their non-zero direct bandgaps, high light absorption coefficients and carrier mobilities, and ability to form atomically sharp and defect-free heterointerfaces. A critical and fundamental bottleneck in the realization of high performance detectors is their trap-dependent photoresponse that trades off responsivity with speed. This work demonstrates a facile method of attenuating this trade-off by nearly 2x through integration of a lateral, in-plane, electrostatically tunable p-n homojunction with a conventional WSe2 phototransistor. The tunable p-n junction allows modulation of the photocarrier population and width of the conducting channel independently from the phototransistor. Increased illumination current with the lateral p-n junction helps achieve responsivity enhancement upto 2.4x at nearly the same switching speed (14–16 µs) over a wide range of laser power (300 pW–33 nW). The added benefit of reduced dark current enhances specific detectivity (D*) by nearly 25x to yield a maximum measured flicker noise-limited D* of 1.1×1012 Jones. High responsivity of 170 A/W at 300 pW laser power along with the ability to detect sub-1 pW laser switching are demonstrated.

Phonon Coupling and Dielectric Response in 2D Semiconductor

NANO ◽  
2021 ◽  
Author(s):  
Arslan Usman ◽  
Abdul Sattar ◽  
Hamid Latif ◽  
Muhammad Imran
Keyword(s):  
Transition Metal Dichalcogenides ◽  
Coupling Mechanism ◽  
Two Dimensional ◽  
Electron Hole ◽  
Exciton Coupling ◽  
Gain Energy ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal ◽  
The Impact

The impact of phonon and their surrounding environment on exciton and its complexes were investigated in monolayer WSe2 semiconductor. Phonon up-conversion has been studied in past for conventional III–V semiconductors, but its role in two-dimensional layered transition metal dichalcogenides has rarely been explored. We investigated the photoluminescence up-conversion mechanism in WSe2 monolayer and found that a lower energy photon gain energy upto 64[Formula: see text]meV to be up-converted to emission photon at room temperature. Moreover, the phonon-exciton coupling mechanism has also been investigated and the role of dielectric screening has been explored to get complete insight of coulomb’s interaction in these electron-hole pairs. Investigations of charge carrier’s lifetime reveal that boron nitride encapsulated monolayer has shorter recombination time as low as 41 ps as compared to a bare monolayer on SiO2 substrate. These results are very promising for realizing spintronics-based application from two-dimensional layered semiconductors.

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