Using density functional theory with meta generalized gradient approximation functional, we investigate scalable electronic and optical properties in twisted hydrogen passivated monolayer black phosphorus nanoribbons (PNRs) by twisting around a specified axis while varying the twisting angle up to 5°. We found that after twisting, the electronic tunability is significant for Armchair configuration of PNR (APNR). We have observed that the bandgap variation of H-passivated APNR upon twisting attains a maximum change of 132 meV per degree twist, and the twisted APNR bandgap is close to the bandgap of oxygen passivated non-twisted ones. Similarly, optical properties of APNR vary significantly upon twisting, which was confirmed by analyzing absorption spectra and optical bandgap. The extended spectral region in twisted APNR, which broadens from the mid-infra-red to the visible region, approaches the oxygenated effect. This tunability of electronic bandgaps and optical properties would ameliorate PNR based optoelectronic devices.

This work examines the prospect of phosphorene antidot nanoribbons (PANRs) using the density functional based tight binding (DFTB) method. Horizontally perforated PANRs with both armchair (A) and zigzag (Z) configurations were considered for electrical simulations. Our simulation results found that the APANRs cannot be scaled down with nanoribbon width, whereas ZPANRs can be scaled easily. Bandgap scaling in terms of ribbon width, length and antidot number was thoroughly analyzed for ZPANRs. In the end, a two-terminal device was constructed and transmission analysis was performed using the non-equilibrium Green's function (NEGF) methodology. A negative differential resistance (NDR) region appeared in the current-voltage characteristics of the ZPANRs, which paved a pathway for nano-device application.

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