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.

scholarly journals Prediction of the structural and electronic properties of MoxTi1−xS2 monolayers via first principle simulations

2020 ◽  
Vol 10 ◽  
pp. 184798042095509
Author(s):  
Ankit Kumar Verma ◽  
Federico Raffone ◽  
Giancarlo Cicero
Keyword(s):  
Transition Metal ◽  
Electronic Properties ◽  
Transition Metal Dichalcogenides ◽  
Stable Phase ◽  
Two Dimensional ◽  
Electron Hole ◽  
Effective Electron ◽  
Wide Range ◽  
Structural And Electronic Properties ◽  
Metal Dichalcogenides

Two-dimensional transition metal dichalcogenides have gained great attention because of their peculiar physical properties that make them interesting for a wide range of applications. Lately, alloying between different transition metal dichalcogenides has been proposed as an approach to control two-dimensional phase stability and to obtain compounds with tailored characteristics. In this theoretical study, we predict the phase diagram and the electronic properties of Mo xTi1− xS2 at varying stoichiometry and show how the material is metallic, when titanium is the predominant species, while it behaves as a p-doped semiconductor, when approaching pure MoS2 composition. Correspondingly, the thermodynamically most stable phase switches from the tetragonal to the hexagonal one. Further, we present an example which shows how the proposed alloys can be used to obtain new vertical two-dimensional heterostructures achieving effective electron/hole separation.

First-principles investigations of vanadium disulfide for lithium and sodium ion battery applications

RSC Advances ◽  
2016 ◽  
Vol 6 (60) ◽  
pp. 54874-54879 ◽  
Author(s):  
Wenhui Wang ◽  
Zhongti Sun ◽  
Wenshuai Zhang ◽  
Quanping Fan ◽  
Qi Sun ◽  
...  
Keyword(s):  
Transition Metal ◽  
First Principles ◽  
Transition Metal Dichalcogenides ◽  
Sodium Ion ◽  
Sodium Ion Battery ◽  
Two Dimensional ◽  
Scientific Interest ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal

Recently, two-dimensional (2D) layered transition metal dichalcogenides (LTMDs) have attracted great scientific interest for ion battery applications.

scholarly journals Layer-dependent quantum cooperation of electron and hole states in the anomalous semimetal WTe2

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Pranab Kumar Das ◽  
D. Di Sante ◽  
I. Vobornik ◽  
J. Fujii ◽  
T. Okuda ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Transition Metal Dichalcogenides ◽  
Photoemission Spectroscopy ◽  
Two Dimensional ◽  
Quantum Phenomenon ◽  
Two Dimensional Materials ◽  
Metal Dichalcogenides ◽  
Electron And Hole States ◽  
Dependent Behaviour

Abstract The behaviour of electrons and holes in a crystal lattice is a fundamental quantum phenomenon, accounting for a rich variety of material properties. Boosted by the remarkable electronic and physical properties of two-dimensional materials such as graphene and topological insulators, transition metal dichalcogenides have recently received renewed attention. In this context, the anomalous bulk properties of semimetallic WTe2 have attracted considerable interest. Here we report angle- and spin-resolved photoemission spectroscopy of WTe2 single crystals, through which we disentangle the role of W and Te atoms in the formation of the band structure and identify the interplay of charge, spin and orbital degrees of freedom. Supported by first-principles calculations and high-resolution surface topography, we reveal the existence of a layer-dependent behaviour. The balance of electron and hole states is found only when considering at least three Te–W–Te layers, showing that the behaviour of WTe2 is not strictly two dimensional.

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’.

The Role of Two-Dimensional Materials in Electromagnetic Interference Shielding

2021 ◽  
pp. 1254-1270
Author(s):  
Rafael Vargas-Bernal
Keyword(s):  
Electromagnetic Interference ◽  
Transition Metal Dichalcogenides ◽  
Environmental Stability ◽  
Two Dimensional ◽  
Shielding Effectiveness ◽  
Electromagnetic Interference Shielding ◽  
Two Dimensional Materials ◽  
Metal Dichalcogenides ◽  
Materials Used ◽  
The Impact

Commonly, metallic materials are used in practical ways to increase the shielding effectiveness (SE) through an appropriately designed assembly process. Unfortunately, the high density of devices that require it and the poor environmental stability of metals have impeded their massive use. In addition, for applications in the automotive, aerospace, and electronics industries, materials with light weight and good chemical stability are also required. The purpose of this chapter is to describe the impact that two-dimensional materials (or 2D materials) are having on the development of materials used for electromagnetic interference shielding, particularly the impulse of materials such as graphene, MXenes, transition metal dichalcogenides (TMDs), and phosphorene. The advances in the last decade are analyzed and alternatives are proposed that will come in the next decades. The shielding mechanisms presented by the two-dimensional materials are analyzed in detail and the specific applications in which these materials can be used are presented.

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