Abstract
Sensitive photodetection is crucial for modern optoelectronic technology. Two-dimensional molybdenum disulfide (MoS2) with unique crystal structure, and extraordinary electrical and optical properties is a promising candidate for ultrasensitive photodetection. Previously reported methods to improve the performance of MoS2 photodetectors have focused on complex hybrid systems in which leakage paths and dark currents inevitably increase, thereby reducing the photodetectivity. Here, we report an ultrasensitive negative capacitance (NC) MoS2 phototransistor with a layer of ferroelectric hafnium zirconium oxide film in the gate dielectric stack. The prototype photodetectors demonstrate a hysteresis-free ultra-steep subthreshold slope of 17.64 mV/dec and ultrahigh photodetectivity of 4.75 × 1014 cm Hz1/2 W−1 at room temperature. 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. These results address the key challenges for MoS2 photodetectors and offer inspiration for the development of other optoelectronic devices.
Highlights
Sensitive photodetection is crucial for modern optoelectronic technology
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]
A metal-ferroelectricinsulator-semiconductor field effect transistor (MFISFET) was fabricated on a p-type silicon substrate, with TiN as the gate metal, HZO/Al2O3 as ferroelectric/insulator gate layers, multilayer MoS2 as the channel semiconductor, and Cr/Au as the source and drain electrodes
Summary
Two-dimensional molybdenum disulfide (MoS2) with unique crystal structure, and extraordinary electrical and optical properties is a promising candidate for ultrasensitive photodetection. 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 These results address the key challenges for MoS2 photodetectors and offer inspiration for the development of other optoelectronic devices. 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]. MoS2 or at the interface between MoS2 and SiO2 substrate, the uncontrollability of trap states caused by material and interface defects, low detectivity, and slow photoresponse on the timescale of seconds seriously limit its practical applications
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