Multiwavelength\nHigh-Detectivity MoS₂ Photodetectors\nwith Schottky Contacts

Abstract

Photodetection is one of the vital functions for the\nmultifunctional\n“More than Moore” (MtM) microchips urgently required\nby Internet of Things (IoT) and artificial intelligence (AI) applications.\nThe further improvement of the performance of photodetectors faces\nvarious challenges, including materials, fabrication processes, and\ndevice structures. We demonstrate in this work MoS₂ photodetectors\nwith a nanoscale channel length and a back-gate device structure.\nWith the mechanically exfoliated six-monolayer-thick MoS₂, a Schottky contact between source/drain electrodes and MoS₂, a high responsivity of 4.1 × 10³ A W^–1, and a detectivity of 1.34 × 10¹³ cm Hz^1/2 W^–1 at 650 nm were achieved.\nThe devices are also sensitive to multiwavelength lights, including\n520 and 405 nm. The electrical and optoelectronic properties of the\nMoS₂ photodetectors were studied in depth, and the working\nmechanism of the devices was analyzed. The photoinduced Schottky barrier\nlowering (PIBL) was found to be important for the high performance\nof the phototransistor.