Abstract
Electronic transport mechanism has been investigated through a modelled one-dimensional carbon chain consisting of four atoms, connected to two identical planar zigzag graphene nanoribbons (ZGNR) electrodes. Non equilibrium green?s function (NGEF) formalism, coupled with density functional theory (DFT) is employed in stabilizing the geometry of the constructed device and in calculating the electronic transmission (conduction) at room temperature. The primitive pristine carbon chain device shows three distinct behaviours in the context of negative differential resistance (NDR) within a small voltage range 0.0-2.0 V. The first nonlinear trend shows a sharp NDR feature. It appears within an extremely low operating voltage range 0.0-0.5 V. Doping with nitrogen and boron atoms in different parts of the device (scattering and electrode region) tends to alter the transport behaviour differently. It is exciting to observe the functioning of the device upon doping in two different ways. Doping in scattering region of the device keeps the shape of I-V curve same in forward and reverse bias operation. However, doping in the electrode region results in altering the shape of I?V curve on biasing differently. Eventually in former case doping in scattering region enhances (amplify) the magnitude of current and in later, doping in electrode region makes it suitable for rectification. Analysis of the computational data generated by the, extremely small device gives exceptionally high values of PVR (peak to value ratio) and rectification ratio. Devices demonstrating high values of these two parameters are of outmost importance and often desired, as they are suitable in performing useful electronic functions. The advantage of the present device over enormous number of similar devices reported in past, being small consisting of only four atoms long carbon chain and short electrodes, its performance potential is comparatively high. The proposed carbon chain device reported here can be utilized as a nano transistor in miniaturized electronic circuitry. Uniqueness of the reported device is its small size coupled with multiple NDR, owing to smallness of dimensions the packing density of such transistors on a single chip operational capability can be increased manifold thereby enhancing its functional performance.