Nanoscale deformation and friction characteristics of atomically thin WSe2 and heterostructure using nanoscratch and Raman spectroscopy
P Manimunda and Y Nakanishi and YM Jaques and S Susarla and CF Woellner and S Bhowmick and SAS Asif and DS Galvao and CS Tiwary and PM Ajayan, 2D MATERIALS, 4, 045005 (2017).
2D transition metals di-selenides are attracting a lot of attention due to their interesting optical, chemical and electronics properties. Here, the deformation characteristics of monolayer, multi-layer WSe2 and its heterostructure with MoSe2 were investigated using a new technique that combines nanoscratch and Raman spectroscopy. The 2D monolayer WSe2 showed anisotropy in deformation. Effect of number of WSe2 layers on friction characteristics were explored in detail. Experimental observations were further supported by MD simulations. Raman spectra recorded from the scratched regions showed strain induced degeneracy splitting. Further nano-scale scratch tests were extended to MoSe2-WSe2 lateral heterostructures. Effect of deformation on lateral hetero junctions were further analysed using PL and Raman spectroscopy. This new technique is completely general and can be applied to study other 2D materials.
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