Robust Metal and Semiconductor Phase Transition Memristor Using Ag‐Intercalated Transition Metal Dichalcogenide
Whan Kyun Kim, Gil Young Cho, Thi Thanh Huong Vu, Jun Sun Son, Yong Ha Shin, Hong Woon Yun, Min Seok Kim, Yong Seon Shin, Heejun Yang, Woo Jong Yu
Abstract
Abstract Metal (1T/1T')‐semiconductor (2H) phase transition memristors (PTMEMs) based on intercalated alkali metal ions (Li + ) in transition metal dichalcogenides (TMDs) exhibit excellent electrical properties, including heterosynaptic plasticity. However, the low stability of Li + ions limits retention and on/off ratios of the PTMEMs. Here, a phase transition in MoTe 2 induced by intercalated Ag + ions is demonstrated for the first time, enabling robust memristor operation. The migration of Ag + ions, controlled by voltage biases, clearly realizes reversible 2H‐1T/1T’ phase transitions, as revealed by transmission electron microscopy, X‐ray photoelectron spectroscopy, and Raman mapping. The memristive mechanism of MoTe 2 shifts from doping (4–8 h) to phase transition (12 h) as Ag intercalation time increases, achieving a 200 000 on/off ratio at a 4 nm thickness. MoTe 2 exhibits the most evident phase transition due to its low transition barrier (0.84) compared to other TMDs (>1.22). Intercalated Ag + ions provide outstanding memristive performance over Li + ions, with a 100 times higher on/off ratio, 300 times better retention, and 8 times lower non‐linearity (β Ag = 0.5–0.6, β Li = 4.0). Ag + MoTe 2 PTMEM achieves 91.7% accuracy in MNIST recognition, surpassing the 81.7% accuracy of Li + MoS 2 PTMEM. These findings demonstrate that Ag + MoTe 2 PTMEM holds great potential for advanced memory‐based neural network applications.