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.