Unravelling the Transport Parameters of Zigzag Graphene Nanorods with Defects and Vacancies

Graphene is a two-dimensional layer of carbon atoms arranged in a hexagonal lattice, only one atom thick.Its exceptional carrier mobility and extremely high thermal conductivity make it attractive for nanoelectronic and energy applications.Although chirality plays a role in determining the electronic properties of graphene, controlling it remains difficult in both zigzag and armchair nanoribbons.So introducing impurities, doping and vacancy in graphene nanorods (GNRs) has been shown to be more effective way for controlling the electronic properties of graphene nanoribbons.The presence of vacancies causes reduction in thermal conductivity.Though AGNR is said to have a better thermal conductivity at higher temperatures, Zigzag GNR (ZGNR) is observed to have a higher thermal conductivity at room temperature.It turns out that GNRs' electronic thermal conductivity rises with temperature.The thermopower is dependent on defects or vacancies, found to improve with its increasing concentration in ZGNR.The disruption of electron-hole energy symmetry is responsible for this improvement with generated defects.Defect-induced changes in the density of states break electron-hole symmetry, which strengthens the Seebeck response and boosts thermopower and results in an improved figure of merit (ZT) in ZGNRs compared to pristine ZGNRs.These variations of ZT is mostly ascribed to the reduction in thermal conductivity caused by the introduced defects.