Field Effect Transistor in Nanoscale
Technical Report,28 Sep 2015,27 Sep 2016
JAWAHARLAL NEHRU CENTRE FOR ADVANCED SCIENTIFIC RESEARCH BANGALORE India
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Weakly coupled molecular junctions are quite active and important field of research as they exhibit various non-linear transport phenomena.The principal investigator has investigated carrier transport through weakly coupled B2C2N2H6 Benzene analogues and BxCyNz Napathalene analogues with x y z10 molecules using quantum many body approach coupled with kinetic master equations. Interestingly, various types of non-linear current voltage characteristics, such as, negative differential conductance NDC, rectifications, Coulomb staircase, which are hallmark of multistate transport devices, have been obtained. Source-drain voltage induced change in the occupation probabilities of low-lying many body states which are different in nature towards carrier transport, directly control the net current flowing through the molecular junctions. A few descriptors the electrode contact points on two rings in case of naphthalene analogueswhich directly dictate the behaviour of I-V characteristics were also found. These predictions would help the experimentalists to know what to expect depending on where the contacts are being probed. Further investigation on the effect of different kinds of perturbations such as, gate voltage and perpendicular optical magnetic field, over carrier flow through the molecular bridges was done. Interestingly, the principal investigator found that depending on the strength of the applied optical magnetic field, several phenomena, such as, switching off current, suppression of NDC features appear in the devices. Fundamentally, the applied perturbations modify both the site charge densities as well as occupation probabilities of transport active channels, resulting in a quite significant alteration in transport behaviour of these molecular junctions.
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