Electrical field and biaxial strain tunable electronic properties of the PtSe₂/Hf₂CO₂ heterostructure

The structure and electronic properties of two-dimensional vertical van der Waals PtSe₂/Hf₂CO₂ heterostructure have been investigated based on first-principles calculations. The results show that the PtSe₂ and Hf₂CO₂ monolayers form a type-I heterostructure with both the conduction band minimum (CBM) and valence band maximum (VBM) located at the Hf₂CO₂ layer. The electronic properties of PtSe₂/Hf₂CO₂ heterostructure can be effectively adjusted by applying external electric field or biaxial strain. The transition in band alignment from type-I to type-II can be manipulated by controlling the strength and direction of the electric field. Additionally, the transition from type-I to type-II have also taken place under the strains, and the band gap of the PtSe₂/Hf₂CO₂ heterostructure decreases with increasing the compressive or tensible strain. Under a strong strain of -8%, the PtSe₂/Hf₂CO₂ heterostructure can transform from semiconductor to metal. These findings provide a promising method to tune the electronic properties of PtSe₂/Hf₂CO₂ heterostructure and design a new vdW heterostructure in the applications for electronic and optoelectronic devices.