Nitrogen doped armchair ZnO nanoribbons for potential rectification applications: DFT analysis

This work investigates the structural, electronic, and transport properties of pristine and N-doped armchair ZnO nanoribbons (ZnONRs) using density functional theory (DFT) in combination with non-equilibrium Green's function (NEGF). It is reported here that the N atom doping at the O atom site slightly reduces the binding energy (Eb) and it also decreases band gap (Eg). For 9-atom width, the pristine structures are most stable with a binding energy of -4.961 eV and a band gap of 2.012 eV. Additionally, the Fermi energy level in doped ZnONRs lies near the valence band thereby induces the p-type characteristics. The transport properties of the two-terminal devices have also been examined. These devices exhibit asymmetric I-V characteristics leading to the rectification phenomenon. Relative to the pristine device, N-doped devices demonstrated improved I-V characteristics. Interestingly, the N-doped two-terminal devices exhibit a higher rectification ratio (RR) in contrast to the pristine device. Similar characteristics are observed for the devices irrespective of width. For the 9-atom width ZnONR devices with N doped at the edge and center positions demonstrate significantly high RR of about 4.54 x 108 and 1.56 x 108 at 1.35 V and 1.0 V bias points, respectively. With such enhanced rectification characteristics, ZnONRs can be used as potential candidates for future nanoelectronic switching devices.