Date of Award

4-2017

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Physics

First Advisor

Noureddine Amrane

Second Advisor

Maamar Benkraouda

Third Advisor

Naser Qamhieh

Abstract

Molybdenum disulfide has some of graphene’s properties but has an edge over graphene as this new 2D nanomaterial has a band gap in its electronic structure, which is absent in graphene. The purpose of this thesis is to study the electronic properties of the promising Molybdenum Disulfide (MoS2) material in its bulk and monolayer forms by undertaking a systematic theoretical approach. We will mainly study the band gap, the density of states and the electronic charge distribution, which is considered as the most important electronic characteristics of semiconductors.

In this study, the density functional theory (DFT) – implemented in WIEN2k and VASP- is used. The generalized gradient approximation (GGA), Modified Becke-Johnson and Hybrid functional approximation are used for the exchange–correlation potential. Band structure, density of states and band gap pressure coefficients are calculated. WSe2 – MoS2 hetero structure and the effect of impurities are covered in this study.

The study matched the experimental results, the band gap of molybdenum disulfide increases with decreasing the number of layers and it shifts from an indirect band gap to a direct band gap when a monolayer MoS2 is formed. The pressure effect found in this study is consistent with the experiments and supports the idea of changing the electrical phase of MoS2 with pressure (from semiconductor to metallic phase).

This study shows that MoS2 is an excellent candidate in electronics industry along with its great applications as lubricant, Transistors and composite applications.

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