First-Principles Investigations of N-Vacancy Induced Zigzag Boron Nitride Nanoribbons for Nanoscale Resonant Tunneling Applications

Abstract: The structural, electronic, and transport properties of zigzag boron nitride nanoribbons (ZBNNRs) with nitrogen-vacancy (N-vacancy) at the center (N-V@C), at the edge (N-V@E), and at the center as well as edge (N-V@CE) are investigated. This work deploys density functional theory (DFT) along with non-equilibrium Green's function (NEGF) formalism. Present DFT-based calculations reveal that a metallic/semiconducting nature can be obtained in N-vacancy ZBNNRs via selective H-passivation. The most structurally stable structure in N-vacancy ZBNNRs is observed for HBN-NV_E irrespective of ribbon width. The current–voltage characteristics of pristine, bare, and N-vacancy ZBNNRs devices demonstrated that the bare ZBNNRs exhibit maximum current as compared to the N-vacancy ZBNNRs device under low bias. This is because the vacancy defect breaks the edge states and produces some localized defect-induced states, which suppress the electron transmission and reduces current to get a better I_P/ I_V (peak to valley current ratio PVCR) ratio. It is worth mentioning here that even negative differential resistance (NDR) with a sufficiently high I_P/ I_V ratio has also been observed for BNH-NV_E of the order of 10¹⁰ in both positive and negative biasing. The observed NDR effect suggests that selective H-passivation in N-vacancy ZBNNRs has immense potential applications for nanoscale NDR devices. Graphic Abstract: [Figure not available: see fulltext.].