Ultrasensitive negative capacitance phototransistors.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31900395.
- Also identified by DOI 10.1038/s41467-019-13769-z and PMC identifier 6941953.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Sensitive photodetection is crucial for modern optoelectronic technology. Two-dimensional molybdenum disulfide (MoS<sub>2</sub>) 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 MoS<sub>2</sub> 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) MoS<sub>2</sub> 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 × 10<sup>14</sup> cm Hz<sup>1/2</sup> W<sup>-1</sup> 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 MoS<sub>2</sub> photodetectors and offer inspiration for the development of other optoelectronic devices.