Quaternary NAND Logic and Complementary Ternary Inverter with p-MoTe₂/n-MoS₂ Heterostack Channel Transistors

Applications of 2D semiconductors have been extensively studied, much oriented to various electron devices. Recently, multivalue field-effect transistors (FETs) are also included among 2D-based electron device studies in consideration that multivalue FETs may resolve power consumption issues in future integrated circuits. Several n-channel devices are thus reported along with a few p-channel devices, while studies to achieve both n- and p-channel multivalue FETs are hardly found. Here, both n- and p-channel multivalue FETs are fabricated using p-MoTe₂/n-MoS₂ heterostack channel architecture, where either p- or n-channel ternary value FET is reproducible by switching the stacking order of p- and n-channel layer. The main ternary value mechanism originates from resonant tunneling type injection and channel inversion, which take place during device operation. For a state-of-the-art device application in 2D electronics, a quaternary NAND logic circuit is for the first time demonstrated by integrating two ternary n-channel FETs, and a complementary ternary inverter is also fabricated by integrating multivalue p-channel and plain n-channel FET.