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

Abstract

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 ∼10¹⁴ 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.