In this study, we developed a method to control the electromechanical response of two-dimensional materials through the application of uniaxial tensile strain. To enable efficient strain transfer, we employed an encapsulation technique in which the edges and backside of the two-dimensional material were embedded within a thin film of polyvinyl alcohol. For electromechanical measurements, electrodes were formed on the backside of the encapsulated specimen using a conductive resin. This method was applied to few-layer 2H-MoS₂, resulting in an encapsulated specimen with backside electrodes. Using a custom-built compact tensile testing device, tensile strains of 0%, 0.5%, and 1.9% were applied to the specimen during piezoelectric force microscope measurements. As a result, we successfully measured an out-of-plane electromechanical response under tensile loading, which is attributed to the converse flexoelectric effect induced by an electric field gradient. At 0.5% strain, the response was enhanced compared to the unloaded state. These results demonstrate that the application of tensile strain can enhance the electromechanical response of two-dimensional materials, providing experimental evidence of strain-tunable flexoelectricity in MoS₂.
HAYASHI et al. (Wed,) studied this question.