Sensitive Electronic-Skin Strain Sensor Array Based on the Patterned Two-Dimensional α-In₂Se₃

Two-dimensional (2D) layered semiconductors have emerged as a highly attractive class of materials for flexible and wearable strain sensor-centric devices such as electronic-skin (e-skin). This is primarily due to their dimensionality, excellent mechanical flexibility, and unique electronic properties. However, the lack of effective and low-cost methods for wafer-scale fabrication of these materials for strain sensor arrays limits their potential for such applications. Here, we report growth of large-scale 2D In₂Se₃ nanosheets by templated chemical vapor deposition (CVD) method, using In₂O₃ and Se powders as precursors. The strain sensors fabricated from the as-grown 2D In₂Se₃ films show 2 orders of magnitude higher sensitivity (gauge factor ∼237 in -0.39% to 0.39% uniaxial strain range along the device channel length) than what has been demonstrated from conventional metal-based (gauge factor: ∼1-5) and graphene-based strain sensors (gauge factor: ∼2-4) in a similar uniaxial strain range. The integrated strain sensor array, fabricated from the template-grown 2D In₂Se₃ films, exhibits a high spatial resolution of ∼500 μm in strain distribution. Our results demonstrate the applicability and highly attractive properties of 2D layered semiconductors in e-skins for robotics and human body motion monitoring.