Strain-induced Type-I to Type-II transition in Janus ZrIBr/MgClBr heterostructure: a DFT study

First-principles calculation is employed to investigate the band alignment, and the strain modulated optoelectronic properties in the Janus ZrIBr/MgClBr heterostructure (HS) within Density Functional Theory (DFT). The two distinct stacking configurations are simulated and one stable arrangement is determined from binding energy, dynamic and thermal stability. The ZrIBr/MgClBr HS possess an indirect bandgap of 1.37 eV. This HS shows the Type-I bandgap making them best appropriate for light emission applications, where electron and hole recombine quickly. This Type-I changes to Type-II band alignment when the strain is applied. Hence, this HS exhibits Type-I and Type-II band structure suitable for the LEDs and photovoltaic application, respectively. The ZrIBr/MgClBr HS displays a broader, unique and outstanding optical absorption within the UV-visible range due to the reduction in energy gaps than isolated ZrIBr and MgClBr monolayer. This research provides a theoretical framework for tuning and designing the 2D HS for the photovoltaic-optoelectronic devices.