Flexible Memristive Device Based on WSe2 Quantum Dots Sandwiched Between Two Poly (Methyl Methacrylate) Layers

In this letter, we demonstrate the fabrication of flexible memristive devices using tungsten di-selenide (WSe
₂
) quantum dots (QDs) as the active layer. The WSe
₂
QDs were synthesized by facile two-step technique consisting of solvothermal and sonication processes to utilize the charge-trapping sites in the memristive devices. The sizes of as-synthesized WSe
₂
QDs, as determined from the transmission electron microscopy image, were in the range between 3 and 5 nm. Current-voltage (I-V) curves for the flexible memristive devices based on nanocomposites consisting of WSe
₂
QDs sandwiched between two poly (methyl methacrylate) (PMMA) layers showed remarkable bi-stable behavior before and after bending. The ON/OFF ratio of the memory devices before and after bending were approximately 1 × 10
²
and 1 × 10
²
, respectively. The devices showed the nonvolatile memory effect with a retention time of more than 7 × 10
²
s. The endurance number of ON/OFF switching cycles for the devices was 1 × 10
²
. The bipolar resistive switching behavior was described on the basis of the I-V results by analyzing the effect of space charge.