Rectifying optoelectronic memory based on WSe₂/graphene heterostructures

Abstract

Van der Waals heterostructures composed of two-dimensional materials vertically stacked have been extensively studied to develop various multifunctional devices. Here, we report WSe2/graphene heterostructure devices with a top floating gate...

Two‐Terminal Self‐Gating Random‐Access Memory Based on Partially Aligned 2D Heterostructures

“…Subsequently, when V was swept back to 0 V, I decreased in a path different from that of I recorded by sweeping V from −13 to +13 V, leading to hysteresis, although its direction was opposite to that of most of the reported FGFETs. [ 35,37,38 ] These results indicate that the nonvolatile memory effects and rectification behavior of the self‐gating diode can be combined using the partially aligned heterostructure with the graphene FG, producing an SGRAM.…”

“…To determine whether the SGRAM also exhibits multilevel memory states, as reported for most FGFETs, [ 35–39 ] V p = −15 V was applied to switch the device to the OFF state and then, the I – V curves were measured by varying the voltage sweep ranges from 10 to 13 V ( Figure a). As the voltage sweep range increased, the conductance increased, which was ascribed to an increase in the number of electrons released from the graphene FG.…”

“…In contrast, when large positive voltages are applied, electrons are released from the graphene FG, increasing the conductance. As a result, the current‐voltage ( I – V ) curves show hysteresis, leading to the nonvolatile memory properties with an on/off ratio of ≈10 4 and retention time > 2 × 10 5 s. Moreover, similar to most reported FGFETs based on 2D materials, [ 35–39 ] the SGRAM exhibits multilevel nonvolatile memory states upon application of repeated voltage pulses or laser illumination pulses, indicating the possibility of its application in the neuromorphic computing. [ 35,38,39 ]…”

Self-Powered Bidirectional Photoresponse in High-Detectivity WSe2 Phototransistor with Asymmetrical van der Waals Stacking for Retinal Neurons Emulation

“…In the artificial retina system, optoelectronic sensors, which can emulate the neuron behaviors in the retina, are indispensable for visible information acquisition. In the past few decades, diverse optoelectronic sensors have been designed for artificial retina systems. − Most of them were based on 2D (two-dimensional) materials because 2D materials are capable of perceiving optical information and converting it into electrical signals for transmission and processing. , Among various 2D materials, tungsten diselenide (WSe 2 ) is drawing increasing attention not only because of its excellent optoelectronic properties but also because of its ambipolar nature. − Recently, WSe 2 -based optoelectronic devices, such as photodiodes, − phototransistors, − and optical memories, , have been demonstrated. Meanwhile, emerging WSe 2 -based devices for artificial retina systems have been proposed, as well …”

New Polymeric Composites Based on Two-Dimensional Nanomaterials for Biomedical Applications

“…[ 8 ]. These make them suitable for a wide range of applications [ 9 ] including gas sensing [ 10 , 11 ], energy storage [ 12 , 13 ], water splitting [ 14 , 15 ], optoelectronics [ 16 , 17 ], water filtration [ 18 , 19 ], and diverse biomedical applications [ 20 ].…”