Abstract: The production of devices in nanoscale with specific
molecular rectifying function is one of the most significant goals in
state-of-art technology. In this work we show by ab initio quantum
mechanics calculations coupled with non-equilibrium Green
function, the design of an organic two-terminal device. These
molecular structures have molecular source and drain with several
bridge length (from five up to 11 double bonds). Our results are
consistent with significant features as a molecular rectifier and can be
raised up as: (a) it can be used as bi-directional symmetrical rectifier;
(b) two devices integrated in one (FET with one operational region,
and Thyristor thiristor); (c) Inherent stability due small intrinsic
capacitance under forward/reverse bias. We utilize a scheme for the
transport mechanism based on previous properties of ¤Ç bonds type
that can be successfully utilized to construct organic nanodevices.
Abstract: In this paper we study a system composed by carbon
nanotube (CNT) and bundle of carbon nanotube (BuCNT) interacting
with a specific fatty acid as molecular probe. Full system is
represented by open nanotube (or nanotubes) and the linoleic acid
(LA) relaxing due the interaction with CNT and BuCNT. The LA has
in his form an asymmetric shape with COOH termination provoking
a close BuCNT interaction mainly by van der Waals force field. The
simulations were performed by classical molecular dynamics with
standard parameterizations.
Our results show that these BuCNT and CNT are dynamically
stable and it shows a preferential interaction position with LA
resulting in three features: (i) when the LA is interacting with CNT
and BuCNT (including both termination, CH2 or COOH), the LA is
repelled; (ii) when the LA terminated with CH2 is closer to open
extremity of BuCNT, the LA is also repelled by the interaction
between them; and (iii) when the LA terminated with COOH is
closer to open extremity of BuCNT, the LA is encapsulated by the
BuCNT. These simulations are part of a more extensive work on
searching efficient selective molecular devices and could be useful to
reach this goal.