Phase-Engineered Molybdenum Telluride/Black Phosphorus Van der Waals Heterojunctions for Tunable Multivalued Logic

Recently, multivalued logic (MVL) circuits have attracted tremendous interest due to their ability to process more data by increasing the number of logic states rather than the integration density. Here, we fabricate logic circuits based on molybdenum telluride (MoTe₂)/black phosphorus (BP) van der Waals heterojunctions with different structural phases of MoTe₂. Owing to the different electrical properties of the 2H and mixed 2H +1T' phases of MoTe₂, tunable logic devices have been realized. A logic circuit based on a BP field-effect transistor (FET) and a BP/MoTe₂ (2H + 1T') heterojunction FET displays the characteristics of binary logic. However, a drain voltage-controlled transition from binary to ternary logic has been observed in BP FET- and BP/ MoTe₂ (2H) heterojunction FET-based logic circuits. Also, a change from binary to ternary characteristics has been observed in BP/MoTe₂ (2H)-based inverters at low temperature below 240 K. We believe that this work will stimulate the assessment of the structural phase transition in metal dichalcogenides toward advanced logic circuits and offer a pathway to substantialize the circuit standards for future MVL systems.