Please use this identifier to cite or link to this item: http://lib.jncasr.ac.in:8080/jspui/handle/10572/2173
Title: Layer specific optical band gap measurement at nanoscale in MoS2 and ReS2 van der Waals compounds by high resolution electron energy loss spectroscopy
Authors: Dileep, K.
Sahu, R.
Sarkar, Sumanta
Peter, Sebastian C.
Datta, Ranjan
Keywords: Physics
Microscope
Nanosheets
Graphene
Issue Date: 2016
Publisher: American Institute Physics
Citation: Dileep, K.; Sahu, R.; Sarkar, S.; Peter, S. C.; Datta, R., Layer specific optical band gap measurement at nanoscale in MoS2 and ReS2 van der Waals compounds by high resolution electron energy loss spectroscopy. Journal of Applied Physics 2016, 119 (11), 9 http://dx.doi.org/10.1063/1.4944431
Journal of Applied Physics
119
11
Abstract: Layer specific direct measurement of optical band gaps of two important van der Waals compounds, MoS2 and ReS2, is performed at nanoscale by high resolution electron energy loss spectroscopy. For monolayer MoS2, the twin excitons (1.8 and 1.95 eV) originating at the K point of the Brillouin zone are observed. An indirect band gap of 1.27 eV is obtained from the multilayer regions. Indirect to direct band gap crossover is observed which is consistent with the previously reported strong photoluminescence from the monolayer MoS2. For ReS2, the band gap is direct, and a value of 1.52 and 1.42 eV is obtained for the monolayer and multilayer, respectively. The energy loss function is dominated by features due to high density of states at both the valence and conduction band edges, and the difference in analyzing band gap with respect to ZnO is highlighted. Crystalline 1T ReS2 forms two dimensional chains like superstructure due to the clustering between four Re atoms. The results demonstrate the power of HREELS technique as a nanoscale optical absorption spectroscopy tool. (C) 2016 AIP Publishing LLC.
Description: Restricted Access
URI: http://hdl.handle.net/10572/2173
ISSN: 0021-8979
Appears in Collections:Research Articles (Ranjan Datta)
Research Papers (Sebastian C. Peter)

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