Open AccessDependence of Raman and absorption spectra of stacked bilayer MoS_2 on the stacking orientation
Author(s) -
Seki Park,
Hyun Kim,
Min Su Kim,
Gang Han,
Jeongyong Kim
Publication year - 2016
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.24.021551
Subject(s) - raman spectroscopy , stacking , materials science , bilayer , raman scattering , photoluminescence , absorption (acoustics) , exciton , molecular physics , optics , optoelectronics , nuclear magnetic resonance , chemistry , condensed matter physics , membrane , biochemistry , physics , composite material
Stacked bilayer molybdenum disulfide (MoS 2 ) exhibits interesting physical properties depending on the stacking orientation and interlayer coupling strength. Although optical properties, such as photoluminescence, Raman, and absorption properties, are largely dependent on the interlayer coupling of stacked bilayer MoS 2 , the origin of variations in these properties is not clearly understood. We performed comprehensive confocal Raman and absorption mapping measurements to determine the dependence of these spectra on the stacking orientation of bilayer MoS 2 . The results indicated that with 532-nm laser excitation, the Raman scattering intensity gradually increased upon increasing the stacking angle from 0° to 60°, whereas 458-nm laser excitation resulted in the opposite trend of decreasing Raman intensity with increasing stacking angle. This opposite behavior of the Raman intensity dependence was explained by the varying resonance condition between the Raman excitation wavelength and C exciton absorption energy of bilayer MoS 2 . Our work sheds light on the intriguing effect of the subtle interlayer interaction in stacked MoS 2 bilayers on the resulting optical properties.