Edge Engineered Graphene Nanoribbons as Nanoscale Interconnect: DFT Analysis

Density functional theory (DFT) with non-equilibrium Green's function (NEGF) formalism and HSPICE simulator have been used to analyse the effect of elemental oxygen atom passivation on the structural, electronic and transport properties of Graphene Nanoribbons (GNRs). The analysis of delay, power dissipation, crosstalk effect, stability and frequency analysis has also been performed to understand its interconnect application. The present study includes all the possible morphologies of zigzag and armchair edge states of GNRs with oxygen and hydrogen passivation. The structural stability of GNRs, analysed in terms of binding energy
$(E_{binding})$
observed that the Zigzag graphene nanoribbon (ZGNR) with both edge oxygen passivated, is the most stable configuration, where stability of the configuration increases with Oxygen concentration. Further, fro
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m the bandstructure and density-of-states calculations, it has been observed that considered 6 atom wide and hydrogen passivated Armchair GNR (AGNR) is semiconducting in nature, whereas, with same width hydrogen passivated ZGNR is metallic. On the other hand, passivation of AGNR with increasing concentration of oxygen form them to metallic in nature. Based on the enhanced metallicity and increment in fermi velocity due to passivation of GNRs with oxygen, these structures may be a potential candidate for interconnects. Their computed electron transport properties, dynamical parameters, delay, power delay product and crosstalk induced delay confirms that the zigzag GNR with both the edges passivated with oxygen (O-ZGNR-O) can be considered as best contender for interconnect application due to its remarkable electrical and thermal transport in comparison to other GNR's. The O-ZGNR-O shows lowest value of kinetic inductance and quantum capacitance of. 01032H/m and 2.21 nF/m respectively with higher stability and higher immunity to crosstalk effect in comparison to other proposed GNRs, which is required for nanoscale interconnects. The relative stability of GNRs have been analyzed in terms of nyquist plot with different interconnect lengths. The results suggest that O-ZGNR-O have lowest delay and power dissipation with higher stability, hence defends its application for interconnect application.