Voltage-Induced Changes in the Transmission Spectrum and Optoelectronic Behavior of Hydrogen-Passivated Graphene Nanoribbons

The transmission spectrum and optical absorption calculations of a hydrogen-passivated zigzag GNR (w = 8) device as a function of the voltage and electromagnetic field (EMF) were evaluated utilizing the TranSIESTA code. The electronic device density of states (DDOS) of the hydrogen-passivated zigzag GNR (w = 8) proves its metallic behavior with Van Hove Singularity (VHS). The values of transmission spectra were calculated using an applied voltage of 1, 2, 3, and 4 V. Moreover, the hydrogen-passivated zigzag GNR device shows a steady current increase from 0 to 21 000 nA with voltage, featuring a plateau between 2.7 and 2.8 V. When an EMF is applied perpendicular to the ribbon plane, there is minimal optical absorption in the graphene nanoribbon due to the lack of direct interaction between the field and electrons as well. However, along the nanoribbon, fluctuations in the EMF induce transitions between electronic states and lead to optical absorption. The z polarization of the incident light results in enhanced absorption in this direction, mainly due to the localized edge states of the GNR. Therefore, the peak optical absorption occurs in the y direction.