Strain Engineering Coupled with Optical Regulation towards High-sensitivity In2S3 Photodetector

摘要： Non-layered 2D materials possess intriguing properties, widening the scope of 2D libraries and promising considerable potential for applications in next-generation optoelectronics. However, due to the surface dangling bonds and weak light adsorption arising from atomically thin thickness, their photosensitivity is still limited. Herein, we achieve an ultrasensitive 2D In2S3 photodetector by adopting strain engineering coupled with optical regulation. A SiO2 nanograting array was introduced to construct strained morphology of 2D In2S3. This morphology induces charge localization and renders back-to-back built-in electric field array, which efficiently suppresses the dark current and separates the photo-excited carriers. Simultaneously, the SiO2 nanograting array realizes light management and improves the light harvesting. As a result, the device presents an ultralow dark current of 3.2 pA with a high signal-to-noise ratio up to 1.7 × 106. Especially, a prominent photoresponsivity of 1810 A/W, an excellent detectivity of 2.09 × 1015 Jones and a fast response speed of 0.41 ms are achieved. This work depicts an effective scheme to associate photonic/electronic properties manipulation for optoelectronic applications.