Study of Grains and Boundaries of Molybdenum Diselenide and Tungsten Diselenide Using Liquid Crystal.

Author(s) Shehzad, M.Arslan; Hussain, S.; Lee, J.; Jung, J.; Lee, N.; Kim, G.; Seo, Y.
Journal Nano Lett
Date Published 2017 Mar 08

Direct observation of grains and boundaries is a vital factor in altering the electrical and optoelectronic properties of transition metal dichalcogenides (TMDs), that is, MoSe2 and WSe2. Here, we report visualization of grains and boundaries of chemical vapor deposition grown MoSe2 and WSe2 on silicon, using optical birefringence of two-dimensional layer covered with nematic liquid crystal (LC). An in-depth study was performed to determine the alignment orientation of LC molecules and their correlation with other grains. Interestingly, we found that alignment of liquid crystal has discrete preferential orientations. From computational simulations, higher adsorption energy for the armchair direction was found to force LC molecules to align on it, compared to that of the zigzag direction. We believe that these TMDs with three-fold symmetric alignment could be utilized for display applications.

DOI 10.1021/acs.nanolett.6b04491
ISSN 1530-6992
Citation Nano Lett. 2017;17(3):14741481.

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