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The unique morphology of 2D van der Waals materials enables them to withstand large deformations and significant nonuniform strain, potentially inducing a strong flexoelectric effect. Despite the size‐dependent flexoelectric effect showing potential for modulating the optoelectronic performance of 2D van der Waals materials, it is far from being fully exploited owing to various challenges. Herein, the use of nanowires with different diameters as the bending media to fabricate 2D α‐In2Se3/β‐InSe heterojunctions with large curvatures of 0.1–1 µm−1 is proposed. The significant band alignment modulation in α‐In2Se3 resulting from the bending‐induced flexoelectric effect is verified through Kelvin probe force microscopy. The strain‐induced piezoelectric effect can be negated because of the weak vdW forces at the interface. The flexoelectric polarization in β‐InSe is screened via the accumulated electrons in the unilateral depleted heterojunction. Compared to the flat heterojunction, the curved heterojunction with an average curvature of 0.9 µm−1 shows 2.48‐fold and 7.62‐fold increases in open‐circuit voltage and zero‐biased responsivity, respectively. This study demonstrates the first successful modulation of photodetection in 2D heterojunctions by exploiting the flexoelectric effect, providing a new perspective for high‐performance 2D vdW optoelectronic devices. [ABSTRACT FROM AUTHOR]

2D ferromagnetic semiconductors are key to next‐generation spintronic devices in the post‐Moore era. The combination of ferromagnetic and optoelectronic properties offers exciting opportunities for advanced multifunctional devices in spin‐optoelectronic applications. Herein, the authors synthesize 2D van der Waals (vdW) CoxSn1‐xS with ferromagnetism and photoresponse through a bottom‐up reaction, which has a high yield compared to typical mechanical exfoliation. Ferromagnetic ordering is realized in 2D vdW semiconductor SnS by Co doping at the Sn sites. Magnetic properties are thoroughly studied at different doping concentrations, and first‐principles calculations are further performed to reveal the magnetism origin and spin interactions. In particular, a low Gilbert damping of 1.69 × 10−3 is obtained in vdW CoxSn1−xS through ferromagnetic resonance. In addition, photodetectors based on CoxSn1−xS quantum dots are demonstrated. These studies establish a promising semiconductor with both ferromagnetic ordering and photoelectric response, which provides unprecedented opportunities in spintronic‐photonic integrated applications. [ABSTRACT FROM AUTHOR]