Two-Dimensional SnSe_2(1-S₂/MoTe₂ Antiambipolar Transistors with Composition Modulation for Multivalued Inverters

Two-dimensional (2D) van der Waals heterostructures that embody the electronic characteristics of each constituent material have found extensive applications. Alloy engineering further enables the modulation of the electronic properties in these structures. Consequently, we envisage the construction and modulation of composition-dependent antiambipolar transistors (AATs) using van der Waals heterostructures and alloy engineering to advance multivalued inverters. In this work, we calculate the electron structures of SnSe_2(1-S₂ alloys and determine the energy band alignment between SnSe_2(1-S₂ and 2H-MoTe₂. We present a series of vertical AATs based on the SnSe_2(1-S₂/MoTe₂ type-III van der Waals heterostructure. These transistors exhibit composition-dependent antiambipolar characteristics through the van der Waals heterostructure, except for the SnSe₂/MoTe₂ transistor. The peak current (I_peak) decreases from 43 nA (x = 0.25) to 0.8 nA (x = 1) at V_ds = -2 V, while the peak-to-valley current ratio (PVR) increases from 4.5 (x = 0.25) to 6.7 × 10³ (x = 1) with a work window ranging from 30 to 47 V. Ultimately, we successfully apply several specific SnSe_2(1-S₂/MoTe₂ devices in binary and ternary logic inverters. Our results underscore the efficacy of alloy engineering in modulating the characteristics of AATs, offering a promising strategy for the development of multivalued logic devices.