Probing Gold-Doped Germanene Nanoribbons for Nanoscale Interconnects Under DFT-NEGF Framework

Abstract

Gold-doped germanene nanoribbons (Au-GeNRs) are investigated for their potential as interconnects, using density functional theory combined with nonequilibrium Green’s function formalism. Various stable doping sites for both zigzag and armchair GeNRs (ZGeNR and AGeNR) are investigated. Based on formation energy ($E_{{{\mathrm{FE}}}}$) analysis, all considered Au-GeNRs are revealed to be thermodynamically stable. The analysis also shows that near-edge-doped ZGeNR (with $E_{{{\mathrm{FE}}}} = -3.46$ eV) is the most stable configuration. It is shown through $E-k$ structures and density-of-states profiles that Au-doping results in metallic GeNR irrespective of the edge states and ribbon width. To further explore the prospects for the use of Au-doped GeNR for interconnect applications, important small-signal dynamic parameters (including $R_Q, L_K,$ and $C_Q$) for various doped configurations are explored. The present investigations also take into account the effect of bias voltage on $R_Q, L_K, C_Q$. It is revealed that, with the exception of the edge-doped ZGeNR configuration, bias voltage has a prominent effect on these parameters for every configuration. Thus, edge-doped ZGeNR (with $L_K = 4.41$ nH/$\upmu$m, $C_Q = 4.21$ pF/cm) represents a potential candidate for nanoscale interconnect applications among the considered configurations.