The Role of Nitrogen Dopant Configurations on Graphite-Based Field-Effect Transistors

In this study, we introduce a novel concept of the transport properties based on the self-consistent charge density functional tight-binding (DFTB) method, and we apply it in three graphite FETs. The Projected Density of States (PDOS) calculations indicate a configuration-dependent electronic response of N-doped graphite: graphitic N increases the density of states near the Fermi level and shifts the local minimum below the Fermi level, consistent with n-type behavior, whereas defectassociated pyridinic N shifts the local minimum above the Fermi level, consistent with p-type behavior. The novelty of this work is therefore not the general observation that nitrogen can modify the carrier character of graphitic materials, but the comparative demonstration that different N configurations produce distinct DOS features and transport responses when implemented in the same graphite-based FET architecture. The outcomes demonstrate that strongly nonlinear I-V can be achieved in defective systems compared to pure ones. Furthermore, these findings show that the doped FETs exhibit similar current values between them in the positive low-voltage zone, and these values are higher than those of the undoped system in the higher voltage range. The N-doping had the effect of increasing the transmission at the Fermi level. Moreover, the presence of graphitic N increased the current significantly more than the other doped system in the high positive voltage area.