Ultrafast and self-driven flexible photodetector based on vertical MoS2/Si heterojunction through enhanced light-trapping structures and Al2O3 interface passivation

Abstract

The self-driven flexible photodetector is vitally important for next-generation optoelectronics. Two-dimensional (2D) molybdenum sulfide (MoS2) as a typical family member of transition-metal dichalcogenides (TMDs) has shown larger potential applications in the high-sensitivity photodetection due to its self-physical properties. Herein, the ultrafast MoS2/Si flexible photodetector with ultrathin Al2O3 passivation interface and high light-trapping structures was fabricated. The MoS2/Al2O3/Si flexible photodetector exhibits excellent performance with a high responsivity of 0.047 A/W, detectivity up to 5.67 × 1011 Jones and rise/fall time of 25.6/3.2 μs. Furthermore, this optoelectronic device can withstand bending angles of 120° and work well after 500 bending times. This unique performance can be attributed to the flexible Si substrate with good mechanical properties, high-light trapping structures and an Al2O3 passivation interface. This device can find potential applications in e-skins, flexible displays and smart health care.