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Evolutions of morphology and electronic properties of few-layered MoS2 exposed to UVO
- Source :
- Results in Physics, Vol 19, Iss, Pp 103634-(2020)
- Publication Year :
- 2020
- Publisher :
- Elsevier, 2020.
-
Abstract
- Ultraviolet-Ozone (UVO) treatment has potentially promoted the long-term stability and the high performance of two-dimensional-material-based devices. However, the detailed evolutions of materials upon UVO treatment are less reported and unclear. Herein, we have systematically investigated the evolutions of morphology and electronic properties of the UVO treated few-layered MoS2. A weak p-doping effect on a 1-hour-UVO-exposed bulk MoS2 is revealed by photoelectron spectroscopy, being attributed to the charge transfer from MoS2 to the newly-formed MoOx. Optical microscopy, atomic force microscopy, Raman and PL mapping measurements reveal an inhomogeneous change of MoS2 morphology after UVO treatment. The oxidation is initiated at intrinsic defect sites and dislocations, and then expands in-plane from dislocations to both sides to form one dimensional standing-wave-like features. The dangling-bond-free surface regions remain smooth, being attributed to the higher energetic barrier for O2 dissociation and chemisorption. A model is proposed to explain the mechanism of inhomogeneous oxidation. The rather different oxidation behavior of MoS2 compared with MoSe2 and MoTe2 can be attributed to the difference in the in-plane chemical bonds. Our findings remind that the device design with UVO oxidation need to take the microstructure changes after treatment into account instead of only taking notice of the doping effect for performance improvement.
- Subjects :
- Materials science
General Physics and Astronomy
02 engineering and technology
01 natural sciences
Dissociation (chemistry)
law.invention
symbols.namesake
Optical microscope
X-ray photoelectron spectroscopy
law
0103 physical sciences
Inhomogeneous oxidation
010302 applied physics
Doping
Ultraviolet ozone
021001 nanoscience & nanotechnology
Microstructure
lcsh:QC1-999
Photoelectron spectroscopy
Chemical bond
Chemical physics
Chemisorption
symbols
Raman and PL spectroscopy
0210 nano-technology
Raman spectroscopy
MoS2
lcsh:Physics
Subjects
Details
- Language :
- English
- ISSN :
- 22113797
- Volume :
- 19
- Database :
- OpenAIRE
- Journal :
- Results in Physics
- Accession number :
- edsair.doi.dedup.....15218968c15e27375aa55e6df6b92a91