High‐Performance Memristors Based on Few‐Layer Manganese Phosphorus Trisulfide for Neuromorphic Computing

Abstract

While transition‐metal thiophosphate (MPX3) materials have been a subject of extensive research in recent years, experimental studies on MPX3‐based memristors are still in their early stages, with device performance being less than ideal. Here, the successful fabrication of high‐yield, high‐performance, and uniform memristors are demonstrated to possess desired characteristics for neuromorphic computing using a single‐crystalline few‐layered manganese phosphorus trisulfide (MnPS3) as a resistive switching medium. The Ti/MnPS3/Au memristor exhibits small switching voltage (<1 V), long memory retention (104 s), fast switching speed (≈20 ns), high On/Off ratio (nearly two orders of magnitude), and simultaneously achieves emulation of synaptic weight plasticity. The microscopic investigation of the structural and chemical characteristics of the few‐layer MnPS3 reveals the presence of structural defects and residual Ti throughout the stacked layer following the application of voltage, which contributes to the uniformity of switching with a low set voltage. With highly linear and symmetric analog weight updates coupled with the capability of accurate decimal arithmetic operations, a high accuracy of 95.15% in supervised learning using the MNIST handwritten recognition dataset is achieved in the artificial neural network. Furthermore, convolutional image processing can be implemented using hardware multiply‐and‐accumulate operation in an experimental memristor crossbar array.

Nondefective Vacancy Enhanced Resistive Switching Reliability in Emergent van der Waals Metal Phosphorus Trisulfide-Based Memristive In-Memory Computing Hardware

“…The involved structure variations of Ag occupation and migration are also investigated, which have not been uncovered in other MPS memristors. , Obvious crystal structure variations are found after Ag occupies V S and V Mn in the MnPS. In particular, compared with the V Mn occupation, the V S occupation has a more remarkable distorted structure, as shown in Figure c–e.…”

“…11,13,14 To the best of our knowledge, only the most common closestacked MPSs with elemental vacancies (such as Mn 2 P 2 S 6 and Ni 2 P 2 S 6 ) are reported as switching mediums. 15,16 The nondefective structural vacancy enabled memristors have not been studied and may provide a high-performance RS paradigm. It is known that the defects in the switching medium, which provide the migration path for the ion movement, have vital influences on the performance and reliability of the memristor.…”

“…Nowadays newly emerged 2D vdW metal phosphorus trisulfides (MPSs) are attracting intense attention because of their unique structures and energy bands. − Most MPSs have wide bandgaps around 3 eV with insulating properties, which may facilitate low leakage currents. , Moreover, various elemental vacancies resulting from the atoms missing from the lattice (i.e., defective vacancies) may potentially exist due to their multielemental composition. More importantly, some MPSs, e.g., In 3/4 P 2 S 6 and SnP 2 S 6 , have unique intrinsic structural vacancies (i.e., nondefective vacancies). ,, To the best of our knowledge, only the most common close-stacked MPSs with elemental vacancies (such as Mn 2 P 2 S 6 and Ni 2 P 2 S 6 ) are reported as switching mediums. , The nondefective structural vacancy enabled memristors have not been studied and may provide a high-performance RS paradigm. It is known that the defects in the switching medium, which provide the migration path for the ion movement, have vital influences on the performance and reliability of the memristor .…”