Strain-tunable MoSe ₂ /ZrCl ₂ heterostructures: first-principles insights into photogalvanic and switching device performance

Two-dimensional (2D) heterostructure materials, known for their tunable multifunctionality and low-dimensional confinement effects, offer vast potential for diverse applications. This work provides a comprehensive investigation of the electronic structure, transport and optical properties of MoSe₂/ZrCl₂ heterostructures using density functional theory (DFT) with non-equilibrium Green's function (NEGF) methods. Our results demonstrate that the electronic properties of MoSe₂/ZrCl₂ heterostructure materials can be precisely tuned by applying biaxial strain. Specifically, biaxial strain triggers a semiconductor-to-metal transition and modulates the bandgap from direct to indirect. In addition, we found that the MoSe₂/ZrCl₂ heterostructure exhibits remarkable optical properties with pronounced absorption peaks in the visible and near-ultraviolet regions. Photodetector simulations reveal substantial photocurrents in the visible range, particularly within the 1.6-3.6 eV photon energy regions, where distinct photocurrent peaks are observed. In addition, the MoSe₂/ZrCl₂ heterostructure-based device exhibits exceptional photodetector performance, with a current switching ratio reaching 10⁸ at +6% biaxial strain. In summary, our study highlights the ability to finely tune the electronic and optical properties of MoSe₂/ZrCl₂ heterostructures through biaxial strain, offering promising prospects for the development of MoSe₂/ZrCl₂-based nano-switching and optoelectronic devices in practical applications.