An Automated System for Strain Engineering and Straintronics of 2D Materials (Adv. Mater. Technol. 1/2023)

Abstract

Strain Engineering In article number 2201091, Andres Castellanos‐Gomez and co‐workers present an automated experimental setup to perform strain engineering experiments with two‐dimensional materials with unprecedented accuracy and reproducibility has been developed. The setup employs a motorized stage and three‐point bending apparatus geometry to control the applied strain on the materials, enabling changes of strain in steps as small as 10−6%.

Bendable Silicene Membranes

“…This is a conventional approach to study strain engineering in 2D materials and so envisages their potential exploitation in straintronic devices. [ 30 ] The applied strain can be derived by measuring the radius of curvature of the sample assuming that the thickness of the sample is negligible compared to those of the flexible polymer and tape (total thickness d ). Moreover, since d is much smaller than the radius of curvature of the osculating circle r (Figure 2a,b) the bending strain can be approximated as ε = d /2 r , and the sample is under pure tensile loading.…”

Built-in tensile strain dependence on the lateral size of monolayer MoS2 synthesized by liquid precursor chemical vapor deposition

“…The breaking of the degeneracy causes the splitting of the E 2g mode in the case of the presence of uniaxial strain larger than 0.8%. 21,27 Fig. 3b reports the statistical analysis of the Raman mode separation, obtained by the Raman maps of a single flake shown in ESI Fig.…”

“…Several previous works have demonstrated the strain dependence of the PL emission energy and intensity. 21,22,27,41,44,67,68 In the case of the MoS 2 monolayer, the standard PL spectrum presents two main peaks attributed to the A and B excitons. The emission energy of the A exciton is reported to vary between 1.82 eV and 1.89 eV, 21,27,68,69 while the B exciton energy varies between 1.97 eV and 2.05 eV, 21,27,44,68,69 In our particular case, Fig.…”

“…21,22,27,41,44,67,68 In the case of the MoS 2 monolayer, the standard PL spectrum presents two main peaks attributed to the A and B excitons. The emission energy of the A exciton is reported to vary between 1.82 eV and 1.89 eV, 21,27,68,69 while the B exciton energy varies between 1.97 eV and 2.05 eV, 21,27,44,68,69 In our particular case, Fig. 5 presents the representative PL spectra of the MoS 2 monolayer grown at increasing temperatures, acquired at the center of the flake.…”

“…Different approaches have been employed for the application of external stress to 2D materials: the most employed one is based on the use of bendable and stretchable polymeric substrates. [21][22][23][24][25][26][27][28] where it is possible to apply mainly uniaxial strain to 2D materials. This approach is mostly used in the fabrication of origami-like 29 and kirigami-like 30,31 MoS 2 based devices, such as strain sensors or optoelectronic devices.…”