Ultrasensitive WSe2/alpha-In2Se3 NIR Photodetector Based on Ferroelectric Gating Effect

Abstract

The suppression of dark current is crucial for enhancing the sensitivity of photodetectors, particularly for infrared photodetection. In this study, to overcome the low sensitivity of photodetectors in the infrared wavelength range, a photodetector comprising a 2D semiconductor (WSe2) heterojunction and 2D ferroelectric semiconductor (alpha-In2Se3) is developed. WSe2 is fully depleted owing to the ferroelectric gating effect of alpha-In2Se3; this enhanced the photodetector detectivity. In addition, photoresponsivity is increased because the n-type alpha-In2Se3 formed a PN junction with the p-type WSe2. Owing to the ferroelectric gating effect of alpha-In2Se3, the dark current in the photodetector is suppressed above 10(3) times, the photoresponsivity is increased 13.8 times from 0.16 to 2.21 A W-1, and the specific detectivity is increased 437 times from 2.18 x 10(8) Jones to 9.52 x 10(10) Jones at a near-infrared (NIR) wavelength of 980 nm. The proposed WSe2/alpha-In(2)Se(3)( )heterostructure with an ultrasensitive characteristic in the NIR wavelength range, can contribute significantly to practical photodetector applications.