Enhanced Photodetection in Sandwiched ZnTe/Bi 2 O 2 Se p-n Junction

Two-dimensional p-n junctions represent pivotal components for post-silicon electronics and optoelectronics in the post-Moore era, yet its traditional preparation method introduces lateral-vertical configuration mismatches between source-drain electrodes and built-in electric fields, resulting in parasitic resistance and chaotic carrier transport. We demonstrate a multistep van der Waals assembly strategy creating a monolithically integrated ZnTe/Bi₂O₂Se heterostructure platform that simultaneously hosts vertical and lateral device architectures across pristine components and their junctions. The vertically configured ZnTe devices exhibit enhanced charge transfer efficiency and photoconversion efficacy compared to lateral counterparts, overcoming intrinsic low conductivity limitations. As for the highly conductive Bi₂O₂Se, although significant enhancement in electrical transport properties was also observed in the vertically configured devices, the photoresponsivity exhibited no substantial improvement due to the reduced optical absorption cross-section. Notably, the vertically sandwiched p-n junction architecture achieves a >100-fold performance enhancement over lateral devices, which is attributable to the synergistic alignment of current pathways and optimized spatial distribution of built-in electric fields. This monolithic integration strategy resolves the persistent dimensionality conflict in conventional 2D p-n junctions, establishing a universal platform for engineering quantum-confined optoelectronic devices with tailored charge transport geometries.