Effect of Electrodes on Negative Differential Resistance in Carbon Nanowire Wire: A First-Principles Study

Applying nonequilibrium Green's function (NEGF) method coupled to density functional theory (DFT) and the Landauer-Buttiker formula, we have carried out electronic transport properties of carbon nanowires with varying number of carbon atoms using two probe device. The transmission spectrum T(E, V-b), as a function of energy and applied bias are analyzed. Out of these, a ten carbon-atoms long nanowire shows negative differential resistance (NDR) behavior inthe current voltage (I-V) characteristics. Molecular system exhibiting NDR acts as potential active components for the development of futuristic miniaturized device applications like memory, switching, logic etc. Electrodes generally changes the transmission and alters the transport properties of the molecular systems. In the present work we have observed that using z-shape graphene nanoribbons (GNRs) junctions, the peak value of current (I-p) is drastically increased to 6879.03 nA as compared to 2725.00 nA (for straight junctions, GNRs) in the onset of NDR region. On the other hand using straight junction reduces the NDR voltage, such devices operating at low bias (activating NDR) are more stable and economical demanding as they consume less power. The proposed ten atom long carbon chain may be considered as functional element in designing molecular devices.