Graphene-based photodiodes with the characteristics of fast photoresponse but low photocurrent gain are hardly suitable for the room-temperature few-photon photodetection. Taking graphene as an example, as its gapless Dirac cone band structure results in ultrafast carrier recombination, graphene–metal junction and graphene p–n junction photodiodes are mainly exploited for separating photogenerated electrons and holes by the built-in electric field 1, 11, 12, 13.

The nature of a 2D optoelectronic material has largely determined the type and the working mechanism of its photodetectors 8, 9, 10. Photodetectors based on two-dimensional (2D) materials, such as graphene 1, 2 and transition metal dichalcogenides 3, 4, 5, have emerged and drawn tremendous attention owing to their unique crystal structures, extraordinary electrical and optical properties, as well as the potential applications in ultrathin, transparent, and flexible optoelectronic devices 6, 7.

Sensitive, fast, and accurate detection of light is the foundation for the future optical communication, memory, sensing, imaging, and other optoelectronic applications. These results address the key challenges for MoS 2 photodetectors and offer inspiration for the development of other optoelectronic devices. The enhanced performance benefits from the combined action of the strong photogating effect induced by ferroelectric local electrostatic field and the voltage amplification based on ferroelectric NC effect. The prototype photodetectors demonstrate a hysteresis-free ultra-steep subthreshold slope of 17.64 mV/dec and ultrahigh photodetectivity of 4.75 × 10 14 cm Hz 1/2 W −1 at room temperature. Here, we report an ultrasensitive negative capacitance (NC) MoS 2 phototransistor with a layer of ferroelectric hafnium zirconium oxide film in the gate dielectric stack. Previously reported methods to improve the performance of MoS 2 photodetectors have focused on complex hybrid systems in which leakage paths and dark currents inevitably increase, thereby reducing the photodetectivity. Two-dimensional molybdenum disulfide (MoS 2) with unique crystal structure, and extraordinary electrical and optical properties is a promising candidate for ultrasensitive photodetection. Sensitive photodetection is crucial for modern optoelectronic technology.

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