Hopping transport through defect-induced localized states in molybdenum disulphide

By Hao Qiu, Tao Xu, Zilu Wang, W. Ren, H. Nan, Zhenhua Ni, Qian Chen, Shijun Yuan, Feng Miao, F. Song and 5 more. Nature Communications, 2013

1,093 citations recorded by the source corpus.

Molybdenum disulphide is a novel two-dimensional semiconductor with potential applications in electronic and optoelectronic devices. However, the nature of charge transport in back-gated devices still remains elusive as they show much lower mobility than theoretical calculations and native n-type doping. Here we report a study of transport in few-layer molybdenum disulphide, together with transmission electron microscopy and density functional theory. We provide direct evidence that sulphur vacancies exist in molybdenum disulphide, introducing localized donor states inside the bandgap. Under low carrier densities, the transport exhibits nearest-neighbour hopping at high temperatures and variable-range hopping at low temperatures, which can be well explained under Mott formalism. We suggest that the low-carrier-density transport is dominated by hopping via these localized gap states. Our study reveals the important role of short-range surface defects in tailoring the properties and device applications of molybdenum disulphide. There is great interest in molybdenum disulphide for electronic devices but the mechanism of charge transport remains elusive. Qiu et al. find that sulphur vacancies introduce localized donor states within the bandgap, enabling low-carrier-density transport via hopping.

Subfields: Biomedical Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/6e890dbb66f6a1a4e644ce32de33080e92165263

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Citations in the corpus

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High Responsivity Phototransistors Based on Few‐Layer ReS2 for Weak Signal Detection (2015, background): “The experimentally measured mobility of ReS2 could have been affected by a few major extrinsic factors, such as charge traps [3], charge impurities [4, 5] and short-range scattering [6].”
Strong photoluminescence enhancement of MoS(2) through defect engineering and oxygen bonding. (2014, background): “Finally, it should be noted that vacancy defects in MoS2would introduce localized donor states inside the band gap of MoS2, and low carrier density transport is dominated by hopping via these localized gap states.(20)”
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