In Situ Synthesis of Two-Dimensional Lateral Semiconducting-Mo:Se//Metallic-Mo Junctions Using Controlled Diffusion...

Two-dimensional (2D) materials are favorable candidates for resistive memories in high-density nanoelectronics owing to their ultrathin scaling and controllable interfacial characteristics. However, high processing temperatures and difficulties in mechanical transfer are intriguing challenges associated with their implementation in large areas with crossbar architecture. A high processing temperature may damage the electrical functionalities of the bottom electrode, and mechanical transfer of 2D materials may introduce undesirable microscopic defects and macroscopic discontinuities. In this study, an in situ fabrication of an electrode and 2D-molybdenum diselenide (MoSe₂) is reported. The controlled diffusion of selenium (Se) in the predeposited molybdenum (Mo) produces Mo//Mo:Se stacks with a few layers of MoSe₂ on top and MoSe on the bottom. Diffusion-assisted Mo//Mo:Se fabrication is observed over a large area (4 in. wafer). Additionally, a 5 × 5 array of crossbar memristors (Mo//Mo:Se//Ag) is fabricated using the diffusion of Se in patterned Mo. These memristors exhibit a small switching voltage (∼1.1 V), high endurance (>250 cycles), and excellent retention (>15 000 s) with minimum cycle-to-cycle and device-to-device variation. Thus, the proposed nondestructive in situ technique not only simplifies the fabrication but also minimizes the number of required stages.