Self-powered broadband, high-detectivity and ultrafast photodetectors based on Pd-MoS2/Si heterojunctions.

In this work, a self-powered photodetector device is fabricated through the integration of a palladium-doped molybdenum disulfide thin film on silicon (Pd-MoS2/Si). The substitution of host Mo atoms with Pd dopants in the MoS2 film is revealed by structural and chemical analysis techniques. Due to the incorporation of Pd atoms into the MoS2 films, the photovoltaic characteristics of the fabricated Pd-MoS2/Si device were enhanced largely, promoting its application as a self-powered photodetector operated at zero bias voltage. The obtained results further show that the device is highly sensitive to broadband wavelengths from ultraviolet to near-infrared light (300-1100 nm). In particular, the Pd-MoS2/Si photodetector shows an ultra-high detectivity of ∼10(14) Jones (Jones = cm Hz(1/2) W(-1)), a responsivity of ∼654.0 mA W(-1), and an ultrafast response speed of ∼2.1 μs. The present work opens new avenues for developing high-performance photodetectors for optical communications and imaging techniques as well as optoelectronic circuits.