Atomically Engineered 2D/Oxide Heterostructure Varistors: Dual-Barrier Tunneling Architecture for Deterministic Nonlinear Switching

Abstract

Deterministic control of tunneling barriers and quantum confinement is central to improving the repeatability and bias stability of voltage-clamping devices. Here we report a deterministically engineered 2D/oxide dual-barrier tunneling stack in which an 8-layer h-BN barrier and a monolayer MoS2 quantum well are inserted to realize resonant-tunneling-assisted voltage clamping with improved repeatability. In this work, we investigate a dual-barrier tunneling varistor based on a vertically integrated ZnO/Bi2O3–Si O2/h-BN/MoS2/Zn7Sb2O12 heterostructure, where an 8-monolayer h-BN barrier (2.0 nm) and a monolayer MoS2 quantum well (0.65 nm) are engineered to promote resonant tunneling near breakdown. The device performance is assessed through combined DFT, self-consistent NEGF–Poisson transport, and FEM electrothermal simulations, together with experimental characterization. The measured semi-logarithmic J–V response exhibits three transport regimes, with a breakdown voltage of Vb = 22.1 V and a peak nonlinearity coefficient of α = 82 ± 3. conditions, as extracted from the self-consistent electrostatic potential and spatially resolved DOS calculations. Monte Carlo analysis over 10,000 virtual devices yields a relative variation of 2.3% in Vb, and cyclic surge testing over 2000 pulses at 2 kA/cm2 shows less than 1% drift in breakdown voltage. These results indicate that the proposed 2D/oxide heterostructure provides a reproducible route for bias-stable voltage clamping through resonant-tunneling-assisted conduction.