Mo/MoSe₂/Ag Memories with In Situ Formation of Mo/MoSe₂ Heterostructures via Selective Diffusion of Se in Mo

Two-dimensional metal chalcogenides (TMDCs) are favorable candidates for high-density memristor crossbar arrays due to their ultrathin scaling limit, controllable interfacial properties, and potentiality in fabricating large-area electronics. However, the fabrication of large area crossbar arrays applied TMDCs has limitations by their high synthesize temperature and difficulty of mechanical transferring on the bottom electrode. The mechanical transfer can induce damages, such as cracks, wrinkles, and impurity residues between the electrode and active layer interface, which could degrade the device performance and uniformity over a large area. In this perspective, the present research involves the fabrication of crossbar array memristor using selectively diffusing selenium (Se) in pre-deposited molybdenum (Mo) to form Mo/MoSe₂ stack in-situ. This effortless way of forming the heterostructures of metal/TMDCs is not limited to Mo/MoSe₂ but can be generalized to a large spectrum of known TMDCs. This in-situ technique introduces an innovative way of forming a continuous mass of Mo/MoSe₂ with good quality interface leading to enhanced performance. Additionally, one-processing step reduction in a large number of sub-processes is introduced in this technique for the first time resulting in a fast and economical way of fabrication of two-terminal resistive memories. The present memories have been operated with small switching voltage (~ 1.1 V), high endurance (> 250 cycles), excellent retention (> 15000 s), minimum cycle-to-cycle and device-to-device variation. This implies that the present technique suggests the way toward non-destructive and easy fabrication of high-performance memristors.