Contents I. Introduction
Since last one decade, we have breached all conventional laws for the scaling of devices and reached to an age of nanoscale devices [1], [2]. At nanoscale, the interconnects face various challenges, that affects their performance like enhanced delay and parasitic effects [3]. Due to reliability issues with aluminum initially used, Aluminum (Al) had been replaced by Copper (Cu). However, the Cu also has few drawbacks at the nanoscale, like the resistance of copper interconnects increases expeditiously due to its small mean free path [4]–[6]. Mean free path of electrons is due to the combined effects of scattering (grain boundary, side wall scattering of electrons) and electro migration. Due to these challenges with Cu interconnects at Nanoscale, the conventional Cu material has been attempted to get replaced by the nanostructures of carbon. Resistance, inductance, capacitance and delay of the device have become more and more pronounced issues for choosing the best interconnect materials. Graphene, an allotrope of carbon is a two dimensional (2D) material, which has 0.34 nm atomic layer of carbon with hexagonal honeycomb structure. This 2D monolayer has various unique properties [7] like high current density with low resistivity, large mean free path, higher superconductivity [10], making it a better and reliable candidate for the next-generation interconnects. In the last few years, the research on one dimensional materials has made remarkable progress, reason being the bulk silicon (Si) technology is approaching its physical limit and inturn challenges like unwanted tunneling [11], leakage currents, and scattering at nanoscale, hence graphene can be considered as the promising candidate to replace Si in future nanoelectronic devices. Graphene nanoribbons (GNRs) are greatly studied, both experimentally and theoretically for possible nanoelectronic device applications [12]–[14]. It can be used as semiconductors or conductors depending on the edge configurations [15], [16], semiconducting graphene can be used in transistor channels while its metallic counterparts can be used in interconnect applications. For the practical implementation, the graphene nanoribbons (GNRs) could be the most suitable for interconnect. Although, the geometric structure changes the property of GNR slightly, compared to the ideal behaviour of graphene [3]. Due to this, graphene nanoribbons have emerged as an interesting material for interconnects application. The most common form of graphene nanoribbons are Zigzag and Armchair, where Zigzag nanoribbons are always metallic and Armchair nanoribbons may be semiconducting or metallic depending on the width.
