Photothermoelectric and photovoltaic effects both present in MoS2

As a finite-energy-bandgap alternative to graphene, semiconducting molybdenum disulfide (MoS 2 ) has recently attracted extensive interest for energy and sensor applications. In particular for broad-spectral photodetectors, multilayer MoS 2 is more appealing than its monolayer counterpart. However,...

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Bibliographic Details
Published in:Scientific reports 2015-01, Vol.5 (1), p.7938-7938, Article 7938
Main Authors: Zhang, Youwei, Li, Hui, Wang, Lu, Wang, Haomin, Xie, Xiaomin, Zhang, Shi-Li, Liu, Ran, Qiu, Zhi-Jun
Format: Article
Language:English
Subjects:
140/133
147/3
639/925/357/1018
639/925/927/1007
Alternative energy sources
Energy
Engineering Science with specialization in Electronics
Graphene
Humanities and Social Sciences
Laboratories
Lasers
Microscopy
Molybdenum
Molybdenum disulfide
multidisciplinary
Photoresponse
Photovoltaics
Scanning
Science
Semiconductors
Teknisk fysik med inriktning mot elektronik
Transistors
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Summary:As a finite-energy-bandgap alternative to graphene, semiconducting molybdenum disulfide (MoS 2 ) has recently attracted extensive interest for energy and sensor applications. In particular for broad-spectral photodetectors, multilayer MoS 2 is more appealing than its monolayer counterpart. However, little is understood regarding the physics underlying the photoresponse of multilayer MoS 2 . Here, we employ scanning photocurrent microscopy to identify the nature of photocurrent generated in multilayer MoS 2 transistors. The generation and transport of photocurrent in multilayer MoS 2 are found to differ from those in other low-dimensional materials that only contribute with either photovoltaic effect (PVE) or photothermoelectric effect (PTE). In multilayer MoS 2 , the PVE at the MoS 2 -metal interface dominates in the accumulation regime whereas the hot-carrier-assisted PTE prevails in the depletion regime. Besides, the anomalously large Seebeck coefficient observed in multilayer MoS 2 , which has also been reported by others, is caused by hot photo-excited carriers that are not in thermal equilibrium with the MoS 2 lattice.
ISSN:2045-2322
2045-2322
DOI:10.1038/srep07938