Changes in differential conductance of vertical MoS₂/WSe₂ van der Waals Heterostructures under voltage, temperature and illumination

In this work, a comprehensive analytical model was developed to describe the dependence of the differential conductance on the applied bias, temperature, and illumination intensity in vertical MoS₂/WSe₂ van der Waals heterostructures. Unlike existing theoretical approaches, the proposed model describes the interrelated effects of thermionic emission, resonant tunneling, and carrier recombination together with the depletion region, the built-in potential (Ubi), Thomas–Fermi electrostatic screening, and Type-II band alignment within a unified analytical framework. The theoretical calculations show that the voltage-dependent evolution of the differential conductance es through three successive transport regimes, namely thermionic emission, resonant tunneling, and negative differential resistance (NDR). Furthermore, increasing temperature reduces the efficiency of resonant tunneling by enhancing electron–phonon interactions, thereby weakening the NDR effect, whereas increasing illumination intensity significantly enhances the differential conductance through photoexciton generation and interlayer charge transfer. The proposed framework enables the quantitative prediction of variations in the resonance voltage, differential conductance, and NDR characteristics under different external conditions. Moreover, it provides a theoretical basis for the modeling and optimization of tunnel diodes, photodetectors, and high-performance nano-optoelectronic devices based on MoS₂/WSe₂ and related Type-II van der Waals heterostructures.

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