Electric-field induced structural transition in vertical MoTe₂- and Mo_1-xW_xTe₂-based resistive memories

Transition metal dichalcogenides have attracted attention as potential building blocks for various electronic applications due to their atomically thin nature and polymorphism. Here, we report an electric-field-induced structural transition from a 2H semiconducting to a distorted transient structure (2H_d) and orthorhombic T_d conducting phase in vertical 2H-MoTe₂- and Mo_1-xW_xTe₂-based resistive random access memory (RRAM) devices. RRAM programming voltages are tunable by the transition metal dichalcogenide thickness and show a distinctive trend of requiring lower electric fields for Mo_1-xW_xTe₂ alloys versus MoTe₂ compounds. Devices showed reproducible resistive switching within 10 ns between a high resistive state and a low resistive state. Moreover, using an Al₂O₃/MoTe₂ stack, On/off current ratios of 10⁶ with programming currents lower than 1 μA were achieved in a selectorless RRAM architecture. The sum of these findings demonstrates that controlled electrical state switching in two-dimensional materials is achievable and highlights the potential of transition metal dichalcogenides for memory applications.