Identification of rhenium donors and sulfur vacancy acceptors in layered MoS{sub 2} bulk samples

Journal Article · Tue Jun 21 00:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4954017· OSTI ID:22596821

Ribeiro, G. M.; Vaz, P. H.; González, J. C.; Krambrock, K. ^[1]

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1. Departamento de Física, Universidade Federal de Minas Gerais, CP 702, 30.123-970 Belo Horizonte, MG (Brazil)

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.

• OSTI ID: 22596821
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 23; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 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