Modulate the Interfacial Oxygen Vacancy for High Performance MoS2 Photosensing−Memory Device

Abstract

AbstractDeveloping memristor with photosensing behavior would facilitate the construction of an advanced neuromorphic computing framework for future sensing−memory−computing integrated system. Although the memristor has already got much attention, its optoelectronic sensing mechanism is still unclear, thus the enhancement is challenging. Herein, a MoS2 memristor is fabricated on the oxygen‐vacancy‐rich Bi1.5MgNb1.5O7 thin film. By combining the voltage stress and photoexcitation, the memristor, its photosensing property, and their correlation have been systematically studied. The results show that the interfacial oxygen vacancy can trap the photogenerated electron obeying the photogating effect which tunes the Fermi level of MoS2 and exhibits tunable hysteresis behavior. The photoexcitation mechanism has been studied showing wavelength and voltage‐dependent photosensing−memory performance. The responsivity can reach up to 2 × 1011 V W−1 at 550 nm illumination and the hysteresis ratio (ΔH/Vg), one of the factors determining the memory, can be modulated by 40 times, which is larger than for previous 2D materials‐based memristors. Contour maps of external quantum efficiency show illumination, voltage, and wavelength dependence where the value becomes larger at lower illumination power density and higher voltage. This study reveals the interfacial enhanced photosensing mechanism of MoS2 device and provides new way to enrich memristor performance.