Design and analysis of monolayer GaN-boron phosphide lateral heterostructures for ultraviolet photodetection and rectification

In the field of materials development, lateral heterostructures (LHSs) have opened new avenues for miniaturized functional devices due to their exceptional physical properties. This study presents the design of a monolayer GaN-boron phosphide (BP) LHSs, with stability validated through molecular dynamics and thermodynamic calculations. Subsequently, we employed first-principles calculations to investigate the correlation between the stability and periodic width of two chiral structures. The results demonstrate that both chiral LHSs exhibit a type-II band alignment, characterized by moderate bandgaps and excellent carrier mobility, with the zigzag direction heterojunction displaying the properties of a direct bandgap semiconductor. Leveraging the monolayer BP-GaN LHSs, we developed a dual-probe device and investigated its photodetection characteristics and rectification behavior using the nonequilibrium Green's function method. Our findings indicate that the zigzag direction BP-GaN LHSs exhibit superior optical responsiveness in the ultraviolet spectrum (318 nm), with a higher responsivity (0.153 A/W), external quantum efficiency (18.944 %), and extinction ratio (6.49). Moreover, the rectification ratio (8 × 10¹¹) significantly surpasses that observed in the zigzag direction. These results suggest that BP-GaN LHSs provide an effective pathway for the integration of rectification and photodetection functionalities within a single optoelectronic nano-device.