<p>Two-dimensional (2D) transition metal dichalcogenide (TMD) heterostructures are promising for next-generation nanoelectronic and optoelectronic devices due to their excellent electronic properties and atomically sharp interfaces. Optimizing these heterostructure-based diodes requires understanding the interplay between material composition, doping, and structural parameters. This study uses finite element method (FEM) simulations to analyze the electrical behavior of four 2D heterostructure diodes, focusing on the high-performance n-MoS₂/p-MoTe₂ junction. A pn junction doping concentration of 5 × 10¹⁷ cm⁻³ reduces series resistance, while its impact on the ideality factor depends on the material system. Ultra-thin channels (~ 1 nm) enhance quantum tunneling through atomically sharp junctions. Electric potential mapping shows that doping transforms the potential profile, forming well-defined built-in fields. A critical oxide thickness of ~ 10 nm minimizes potential barriers, improving carrier injection and reducing noise. These findings offer practical guidelines for designing efficient 2D heterostructure devices and support integration into scalable nanoelectronic systems.</p> Graphical abstract <p>Electric potential distribution in 2D heterostructure diode devices under different channel and insulator configurations. (a) 3D device structure showing source, drain, and layered channel materials with triangular meshing. (b) Volume electric potential profile across the channel. (c) Comparative electric potential distributions for doped and undoped channels at different channel thicknesses (1 nm and 5 nm), with a fixed SiO₂ insulator thickness of 250 nm</p> <p></p>