Extended Huckel DFT-based study of Icosagens passivation at the edge of armchair graphene nanoribbon for next generation nanoelectronics applications

Abstract

This study explores the impact of edge passivation of pristine armchair graphene nanoribbons (P–AGNRs) with Icosagens group elements - boron (B), aluminum (Al), gallium (Ga), and indium (In) on the performance of graphene nanoribbon field-effect transistors (GNRFETs) for next-generation nano electronic applications. Using a tight-binding Hamiltonian with the Extended Huckel (EH) model and non-equilibrium Green's function (NEGF) approach under a self-consistent formalism (SCF), we evaluate key parameters such as spectral densities, real-space density, Hartree potential, transmission coefficient T(E), and drain current (I_d). The passivation with Icosagens significantly reduces the bandgap, enhances the density of states (DOS), and increases T(E), compared to pristine AGNRs. These passivated AGNRs, when used as channel materials in gate stack GNRFETs (GS–GNRFETs), demonstrate remarkable improvements: I_on increases from 1.06 μA to 18.4 μA, I_off decreases from 1.49 × 10⁻¹⁰ A to 5.43 × 10⁻¹⁶ A, and the switching ratio (SR) improves from 0.711 × 10⁴ to 0.35 × 10¹⁰. Analysis of analog performance metrics such as transconductance (g_m) and device efficiency (DE) reveals that passivation with heavier Icosagens (Al, Ga) enables stronger electrostatic control and enhanced electron transport. Transmission spectrum (TS) and projected local density of states (PLDOS) analyses further support the above findings and the PLDOS contours and transmission pathways (TP) indicating higher tunneling probabilities in Al and Ga - passivated structures. Overall, Al and Ga - GNRFETs emerge as highly promising candidates for high-speed logic, low-power memory, quantum computing, and neuromorphic applications due to their superior switching, low leakage, and efficient charge transport.