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Author Brandão, F. D. ♦ Ribeiro, G. M. ♦ Vaz, P. H. ♦ González, J. C. ♦ Krambrock, K.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY ♦ CONCENTRATION RATIO ♦ CRYSTALS ♦ DEFECTS ♦ ELECTRON SPIN RESONANCE ♦ ELECTRONIC EQUIPMENT ♦ ENERGY GAP ♦ IMPURITIES ♦ IONIZATION ♦ MOLYBDENUM SULFIDES ♦ OPTICAL PROPERTIES ♦ PARAMAGNETISM ♦ RHENIUM ♦ SEMICONDUCTOR DEVICES ♦ SEMICONDUCTOR MATERIALS ♦ SILICON OXIDES ♦ SULFUR ♦ TEMPERATURE DEPENDENCE ♦ TEMPERATURE RANGE 0065-0273 K ♦ TWO-DIMENSIONAL CALCULATIONS ♦ VACANCIES
Abstract MoS{sub 2} monolayers, a two-dimensional (2D) direct semiconductor material with an energy gap of 1.9 eV, offer many opportunities to be explored in different electronic devices. Defects often play dominant roles in the electronic and optical properties of semiconductor devices. However, little experimental information about intrinsic and extrinsic defects or impurities is available for this 2D system, and even for macroscopic 3D samples for which MoS{sub 2} shows an indirect bandgap of 1.3 eV. In this work, we evaluate the nature of impurities with unpaired spins using electron paramagnetic resonance (EPR) in different geological macroscopic samples. Regarding the fact that monolayers are mostly obtained from natural crystals, we expect that the majority of impurities found in macroscopic samples are also randomly present in MoS{sub 2} monolayers. By EPR at low temperatures, rhenium donors and sulfur vacancy acceptors are identified as the main impurities in bulk MoS{sub 2} with a corresponding donor concentration of about 10{sup 8–12} defects/cm{sup 2} for MoS{sub 2} monolayer. Electrical transport experiments as a function of temperature are in good agreement with the EPR results, revealing a shallow donor state with an ionization energy of 89 meV and a concentration of 7 × 10{sup 15 }cm{sup −3}, which we attribute to rhenium, as well as a second deeper donor state with ionization energy of 241 meV with high concentration of 2 × 10{sup 19 }cm{sup −3} and net acceptor concentration of 5 × 10{sup 18 }cm{sup −3} related to sulfur vacancies.
ISSN 00218979
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-06-21
Publisher Place United States
Journal Journal of Applied Physics
Volume Number 119
Issue Number 23


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