Solid-Ionic Memory in a van der Waals Heterostructure

Abstract

Defect states dominate the performance of low-dimensional nanoelectronics, which deteriorate the serviceability of devices in most cases. But in recent years, some intriguing functionalities are discovered by defect engineering. In this work, we demonstrate a bifunctional memory device of a MoS2/BiFeO3/SrTiO3 van der Waals heterostructure, which can be programmed and erased by solely one kind of external stimuli (light or electrical-gate pulse) via engineering of oxygen-vacancy-based solid-ionic gating. The device shows multibit electrical memory capability (>22 bits) with a large linearly tunable dynamic range of 7.1 × 106 (137 dB). Furthermore, the device can be programmed by green- and red-light illuminations and then erased by UV light pulses. Besides, the photoresponse under red-light illumination reaches a high photoresponsivity (6.7 × 104 A/W) and photodetectivity (2.12 × 1013 Jones). These results highlighted solid-ionic memory for building up multifunctional electronic and optoelectronic devices.

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

“…However, it should be noted that the higher gate voltage is due to the thick SiO 2 and BMN dielectric layer. [ 6 ] By optimizing the device, it will be possible to realize reading with lower voltage in the future.…”

“…In this work, however, we introduce a newly defined EQE to make this measurement accordant with the previous discussions. We combine the ΔH with the EQE by substituting Equation 1 and Equation 5 into Equation 4 and get Equation 6: (6) where E ph is the energy of a photon, t is the time taken for one hysteresis loop to sweepand C 0 is the shunt capacitance density of SiO 2 and BMN. [29] Note that the capacitance density of BMN is a lot greater than that of the MoS 2 , so the capacitance density of the double layer, calculated by…”

“…When a negative pulse is applied, the electrons in MoS 2 are transferred to the interface and captured by the capture site of the SiO 2 layer, and the conductivity of the device decreases, which has also been reported in other 2D materials-based optoelectronic memristors. [4,6,24,25] Although optoelectronic memristors already get much attention, the tunable optoelectrical effect and its effect on the 2D materials-based optoelectronic memristor is still unclear. [26,27] Herein, we try to probe into the mechanism of the optical stimulations in a charge-trapping-based MoS 2 optoelectronic memristor by constructing a MoS 2 /Bi 1.5 MgNb 1.5 O 7 (BMN) heterostructure interface.…”

“…Thus, the memristor has been considered as an important hardware basis for constructing advanced neuromorphic computing and is further expected to fundamentally break through the bottleneck of traditional von Neumann computer system architecture and greatly improve data processing speed and energy efficiency. [ 5–7 ]…”

“…architecture and greatly improve data processing speed and energy efficiency. [5][6][7] The introduction of sensing functionality and the integration of sensing, storage, and operation will help to develop a more intelligent and energy-efficient computing system, which is expected to open a new era of artificial intelligence. Therefore, the memristor, which combines sensing, memory, and computing, has become a hotspot of research recently.…”