RESUMEN
Low-temperature large-area growth of two-dimensional (2D) transition-metal dichalcogenides (TMDs) is critical for their integration with silicon chips. Especially, if the growth temperatures can be lowered below the back-end-of-line (BEOL) processing temperatures, the Si transistors can interface with 2D devices (in the back end) to enable high-density heterogeneous circuits. Such configurations are particularly useful for neuromorphic computing applications where a dense network of neurons interacts to compute the output. In this work, we present low-temperature synthesis (400 °C) of 2D tungsten diselenide (WSe2) via the selenization of the W film under ultrahigh vacuum (UHV) conditions. This simple yet effective process yields large-area, homogeneous films of 2D TMDs, as confirmed by several characterization techniques, including reflection high-energy electron diffraction, atomic force microscopy, transmission electron microscopy, and different spectroscopy methods. Memristors fabricated using the grown WSe2 film are leveraged to realize a novel compact neuron circuit that can be reconfigured to enable homeostasis.
RESUMEN
Threshold switches based on conductive metal bridge devices are useful as selectors to block sneak leakage paths in memristor arrays used in neuromorphic computing and emerging nonvolatile memory. We demonstrate that control of Ag-cation concentration in Al2O3 electrolyte and Ag filament size and density play an important role in the high on/off ratio and self-compliance of metal-ion-based volatile threshold switching devices. To control Ag-cation diffusion, we inserted an engineered defective graphene monolayer between the Ag electrode and the Al2O3 electrolyte. The Ag-cation migration and the Ag filament size and density are limited by the pores in the defective graphene monolayer. This leads to quantized conductance in the Ag filaments and self-compliance resulting from the formation and dissolution of the Ag conductive filament.