Controlled growth of vertically stacked In2Se3/WSe2 heterostructures for ultrahigh responsivity photodetector

Transition metal dichalcogenides (TMDCs) are promising candidates for future optoelectronic devices accounting for their high carrier mobility and excellent quantum efficiency. However, the limited light absorption efficiency in atomically thin layers significantly hinders photocarrier generation, thereby impairing the optoelectronic performance and hindering practical applications. Herein, we successfully synthesized In2Se3/WSe2 heterostructures through a typical two-step chemical vapor deposition (CVD) method. The In2Se3 nanosheet with strong light absorption capability, serving as the light absorption layer, was integrated with the monolayer WSe2, enhancing the photosensitivity of WSe2 significantly. Upon laser irradiation with a wavelength of 520 nm, the In2Se3/WSe2 heterostructure device shows an ultrahigh photoresponsivity with a value as high as 2333.5 A/W and a remarkable detectivity reaching up to 6.7 × 1012 Jones, which is the highest among almost the reported TMDCs-based heterostructures grown via CVD even some fabricated by mechanical exfoliation (ME). Combing the advantages of CVD method such as large scale, high yield, and clean interface, the In2Se3/WSe2 heterostructures would provide a novel path for future high-performance optoelectronic device.