Electronic properties of phosphorene nanoribbons with nanoholes.

Using first-principles calculation based on density-functional theory, the electronic properties of monolayer black phosphorus nanoribbons (PNRs) with and without punched nanoholes (PNRPNHs) and their mechanical stability are studied systematically. We show that while the perfect PNRs and the PNRPNHs have similar properties as semiconductors in both armchair-edge PNR and zigzag-edge PNR structures, the nanoholes can lead to changes in the electronic structure: the zigzag-edge PNRPNH undergoes a direct-to-indirect bandgap transition while the armchair-edge PNRPNH still retains a direct bandgap but with a significant increase in the bandgap as compared to the perfect PNRs. We found also that nanoholes have little influence on the structural stability of PNRs; but the applied external transverse electric field and strain can be more effective in modulating the bandgaps in the PNRPNHs. These new findings show that PNRs are a promising candidate for future nanoelectronic and optoelectronic applications.