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Title: Optoelectronic response and excitonic properties of monolayer MoS{sub 2}

Abstract

Ab initio, electronic energy bands of MoS{sub 2} single layer are reported within the local density functional approximation. The inclusion of spin orbit coupling reveals the presence of two excitons A and B. We also discuss the change of physical properties of MoS{sub 2} from multilayer and bulk counterparts. The nature of the band gap changes from indirect to direct when the thickness is reduced to a single monolayer. The imaginary and real dielectric functions are investigated. Refractive index and birefringence are also reported. The results suggest that MoS{sub 2} is suitable for potential applications in optoelectronic and photovoltaic devices. The ab initio study is essential to propose the crucial parameters for the analytical model used for A-B exciton properties of the monolayer MoS{sub 2}. From a theoretical point of view, we consider how the exciton behavior evolves under environmental dielectrics.

Authors:
 [1];  [1];  [2];  [1];  [2]
  1. Laboratoire de Physique de la Matière Condensée, Faculté des Sciences de Tunis, Université Tunis El Manar Campus Universitaire, 2092 (Tunisia)
  2. (Tunisia)
Publication Date:
OSTI Identifier:
22597794
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 5; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; APPROXIMATIONS; BIREFRINGENCE; DENSITY FUNCTIONAL METHOD; DIELECTRIC MATERIALS; EXCITONS; LAYERS; L-S COUPLING; MOLYBDENUM SULFIDES; PHOTOVOLTAIC EFFECT; REFRACTIVE INDEX; SILICON OXIDES; SPIN; THICKNESS

Citation Formats

Ben Amara, Imen, Ben Salem, Emna, E-mail: bensalem-emna@yahoo.fr, Institut Préparatoire aux Etudes d'Ingénieurs de Tunis, 2, Rue Jawaher Lel Nahrou-Monfleury, 1008 Tunis, Jaziri, Sihem, and Laboratoire de Physique des Matériaux, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Jarzouna. Optoelectronic response and excitonic properties of monolayer MoS{sub 2}. United States: N. p., 2016. Web. doi:10.1063/1.4958948.
Ben Amara, Imen, Ben Salem, Emna, E-mail: bensalem-emna@yahoo.fr, Institut Préparatoire aux Etudes d'Ingénieurs de Tunis, 2, Rue Jawaher Lel Nahrou-Monfleury, 1008 Tunis, Jaziri, Sihem, & Laboratoire de Physique des Matériaux, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Jarzouna. Optoelectronic response and excitonic properties of monolayer MoS{sub 2}. United States. doi:10.1063/1.4958948.
Ben Amara, Imen, Ben Salem, Emna, E-mail: bensalem-emna@yahoo.fr, Institut Préparatoire aux Etudes d'Ingénieurs de Tunis, 2, Rue Jawaher Lel Nahrou-Monfleury, 1008 Tunis, Jaziri, Sihem, and Laboratoire de Physique des Matériaux, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Jarzouna. Sun . "Optoelectronic response and excitonic properties of monolayer MoS{sub 2}". United States. doi:10.1063/1.4958948.
@article{osti_22597794,
title = {Optoelectronic response and excitonic properties of monolayer MoS{sub 2}},
author = {Ben Amara, Imen and Ben Salem, Emna, E-mail: bensalem-emna@yahoo.fr and Institut Préparatoire aux Etudes d'Ingénieurs de Tunis, 2, Rue Jawaher Lel Nahrou-Monfleury, 1008 Tunis and Jaziri, Sihem and Laboratoire de Physique des Matériaux, Faculté des Sciences de Bizerte, Université de Carthage, 7021 Jarzouna},
abstractNote = {Ab initio, electronic energy bands of MoS{sub 2} single layer are reported within the local density functional approximation. The inclusion of spin orbit coupling reveals the presence of two excitons A and B. We also discuss the change of physical properties of MoS{sub 2} from multilayer and bulk counterparts. The nature of the band gap changes from indirect to direct when the thickness is reduced to a single monolayer. The imaginary and real dielectric functions are investigated. Refractive index and birefringence are also reported. The results suggest that MoS{sub 2} is suitable for potential applications in optoelectronic and photovoltaic devices. The ab initio study is essential to propose the crucial parameters for the analytical model used for A-B exciton properties of the monolayer MoS{sub 2}. From a theoretical point of view, we consider how the exciton behavior evolves under environmental dielectrics.},
doi = {10.1063/1.4958948},
journal = {Journal of Applied Physics},
number = 5,
volume = 120,
place = {United States},
year = {Sun Aug 07 00:00:00 EDT 2016},
month = {Sun Aug 07 00:00:00 EDT 2016}
}
  • Semiconducting 2D materials, like transition metal dichalcogenides (TMDs), have gained much attention for their potential in opto-electronic devices, valleytronic schemes, and semi-conducting to metallic phase engineering. However, like graphene and other atomically thin materials, they lose key properties when placed on a substrate like silicon, including quenching of photoluminescence, distorted crystalline structure, and rough surface morphology. The ability to protect these properties of monolayer TMDs, such as molybdenum disulfide (MoS 2), on standard Si-based substrates, will enable their use in opto-electronic devices and scientific investigations. Here we show that an atomically thin buffer layer of hexagonal-boron nitride (hBN) protects themore » range of key opto-electronic, structural, and morphological properties of monolayer MoS 2 on Si-based substrates. The hBN buffer restores sharp diffraction patterns, improves monolayer flatness by nearly two-orders of magnitude, and causes over an order of magnitude enhancement in photoluminescence, compared to bare Si and SiO 2 substrates. Lastly, our demonstration provides a way of integrating MoS 2 and other 2D monolayers onto standard Si-substrates, thus furthering their technological applications and scientific investigations.« less
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