Phase engineered molybdenum telluride/black phosphorus van der Waals heterojunction for tunable multivalued logic.

Recently, multi-valued 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 heterojunction with different structural phases of MoTe2. Owing to the different electrical properties of 2H and mixed 2H +1T' phase of MoTe2, tunable logic devices have been realized. Logic circuit based on BP field-effect transistor (FET) and BP/MoTe2 (2H+1T') heterojunction FET displays the characteristics of a 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 circuit. Also a change from binary to ternary characteristics has also been observed in BP/MoTe2 (2H) based inverter at low temperature below 240 K. We believe that this work will stimulate assessment on the structural phase transition in metal dichalcogenides towards advanced logic circuits and offers a pathway to substantialize the circuit standards for future MVL systems.