Current-voltage model of a graphene nanoribbon p-n junction and Schottky junction diode

Abstract

This work presents a simplified analytical model of a p-n junction diode based on a graphene nanoribbon (GNR) and a unique type of Schottky diode based on metallic graphene and semi-conducting GNRs. Due to the one-dimensional nature of GNRs, their electrostatic analyses need to be quite different from that of bulk devices. Two approaches have been taken to model the charge distribution in this depletion region, namely, the point charge approximation for the GNR p-n junction diode and the line charge approximation for the graphene/GNR Schottky diode. Analytical expressions for the spatial distribution of electric field and potential have been derived and the results are quite distinct from their bulk counterparts. The current-voltage relation of each diode has been investigated within the approximation of Shockley's law of junctions. The width dependency of the currents for these diodes has also been modelled and it has been found that the current density of both the diodes decreases with decreasing width. Such an analysis can encourage the modelling of next-generation GNR-based high-speed electronic devices.