Charge transport through the multiple end zigzag edge states of armchair graphene nanoribbons and heterojunctions

TL;DR

This study explores charge transport in armchair graphene nanoribbons heterojunctions, revealing how edge states and electric fields influence tunneling and energy levels, with implications for room-temperature single-electron transistors.

Contribution

It provides new insights into the modulation of edge state energy levels and tunneling behavior in GNR heterojunctions under electric fields, advancing potential applications in nanoelectronics.

Findings

Edge states exhibit a blue Stark shift under electric field.

Charge tunneling is facilitated by subband states.

Nonthermal broadening enhances tunneling current peaks.

Abstract

This comprehensive study investigates charge transport through the multiple end zigzag edge states of finite-size armchair graphene nanoribbons/boron nitride nanoribbons (n-AGNR/w-BNNR) junctions under a longitudinal electric field, where n and w denote the widths of the AGNRs and the BNNRs, respectively. In 13-atom wide AGNR segments, the edge states exhibit a blue Stark shift in response to the electric field, with only the long decay length zigzag edge states showing significant interaction with the red Stark shift subband states. Charge tunneling through such edge states assisted by the subband states is elucidated in the spectra of the transmission coefficient. In the 13-AGNR/6-BNNR heterojunction, notable influences on the energy levels of the end zigzag edge states of 13-AGNRs induced by BNNR segments are observed. We demonstrate the modulation of these energy levels in resonant tunneling situations, as depicted by bias-dependent transmission coefficient spectra. Intriguing nonthermal broadening of tunneling current shows a significant peak-to-valley ratio. Our findings highlight the promising potential of n-AGNR/w-BNNR heterojunctions with long decay length edge states in the realm of GNR-based single electron transistors at room temperature.