摘要： p-n heterostructure (HTS) is a fundamental component for high-performance electronic and optoelectronic device. Vertical stacking through van der Waals (vdW) force is emerging as a feasible technique to construct p-n HTS. Herein, we designed a novel kind of direct-bandgap C3N monolayer, via adjusting the arrangement of C and N atoms in C3N hexagonal cell. On the basis of the density functional theory combined with the non-equilibrium Green’s function method, we built two-dimensional vdW-contact phosphorene (BP)/C3N p-n HTS, and analyzed its electronic and optical properties in comparison with the inplane-jointed ones. The strong charge transfer between BP and C3N segments results in a wide bandgap of 0.48 eV for joint-contact type BP/C3N HTS, whereas the effective interlayer coupling in vdW-contact type leads to an improved light adsorption as compared to the isolated C3N monolayer. By fabricating dual-gated BP/C3N HTS field-effect transistors (FETs), the dynamic transport behaviors demonstrated that the band bending under a lower threshold voltage makes band-to-band tunneling possible for vdW-contact type. Our work suggests that vdW-contact type is superior to joint-contact type in constructing p-n HTS for high-performance electronic and optoelectronic devices.