Local Strain Engineering in Atomically Thin MoS₂

Abstract

Controlling the bandstructure through local-strain engineering is an exciting avenue for tailoring optoelectronic properties of materials at the nanoscale. Atomically thin materials are particularly well suited for this purpose because they can withstand extreme non-homogeneous deformations before rupture. Here, we study the effect of large localized strain in the electronic bandstructure of atomically thin MoS 2 . Using photoluminescence imaging, we observe a strain-induced reduction of the direct bandgap, and funneling of photogenerated excitons towards regions of higher strain.To understand these results, we develop a non-uniform tight-binding model to calculate the electronic properties of MoS 2 nanolayers with complex and realistic local strain geometries, finding good agreement with our experimental results.

Strain and structure heterogeneity in MoS2 atomic layers grown by chemical vapour deposition

“…The corresponding difference in strain is estimated to be B0.2%. Although the DFT simulations do not account for the excitonic effects, the relative change of the calculated bandgap with respect to uniaxial strain ( À 44 meV per % strain) matches quite well with previous experiments on the PL peak position shift with strain ( À 45 meV per % strain 26 and À 36 meV per % strain 27 . Furthermore, as we mentioned, due to the fast cooling, a global tensile strain is found in MoS 2 .…”

Spectroscopic Signatures for Interlayer Coupling in MoS2–WSe2 van der Waals Stacking

“…40 The result of Raman scattering modes is shown in Figure 3, where all the modes, not the resonant second order or combinations of first order modes, are shown in the It is known that the Raman E' peak of monolayer MoS2 is sensitive to strain and strain could induce a red-shift in the E' modes that have been observed for MoS2 monolayer or multilayers in other reports. 33,[41][42][43] The red-shift of the MoS2 E' peak after the two layers are coupled (thermally treated)…”

Outermost tensile strain dominated exciton emission in bending CdSe nanowires

“…For example, significant energy redshifts of the near-band-edge (NBE) luminescence in uniaxial strain modulated ZnO [15] and GaAs [16] nanowires, as well as in curved ZnO [17][18][19][20] and CdS [21] micro/nanowires have been observed. It has also been reported that the elastic strain-gradient can effectively modulate the photoexcited carrier and exciton dynamics in MoS 2 atomic membrane [7,22] and ZnO micro/ nanowires [23,24].…”