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Accurate identification of layer number for few-layer WS2 and WSe2 via spectroscopic study.
- Source :
-
Nanotechnology . 3/23/2018, Vol. 29 Issue 12, p1-1. 1p. - Publication Year :
- 2018
-
Abstract
- Transition metal dichalcogenides (TMDs) with a typical layered structure are highly sensitive to their layer number in optical and electronic properties. Seeking a simple and effective method for layer number identification is very important to low-dimensional TMD samples. Herein, a rapid and accurate layer number identification of few-layer WS2 and WSe2 is proposed via locking their photoluminescence (PL) peak-positions. As the layer number of WS2/WSe2 increases, it is found that indirect transition emission is more thickness-sensitive than direct transition emission, and the PL peak-position differences between the indirect and direct transitions can be regarded as fingerprints to identify their layer number. Theoretical calculation confirms that the notable thickness-sensitivity of indirect transition derives from the variations of electron density of states of W atom d-orbitals and chalcogen atom p-orbitals. Besides, the PL peak-position differences between the indirect and direct transitions are almost independent of different insulating substrates. This work not only proposes a new method for layer number identification via PL studies, but also provides a valuable insight into the thickness-dependent optical and electronic properties of W-based TMDs. [ABSTRACT FROM AUTHOR]
- Subjects :
- *PHOTOLUMINESCENCE
*DENSITY functional theory
*SEMICONDUCTORS
Subjects
Details
- Language :
- English
- ISSN :
- 09574484
- Volume :
- 29
- Issue :
- 12
- Database :
- Academic Search Index
- Journal :
- Nanotechnology
- Publication Type :
- Academic Journal
- Accession number :
- 127944317
- Full Text :
- https://doi.org/10.1088/1361-6528/aaa923