Investigating the influence of electrode Miller indices alteration on electronic transport in thiophene-based molecular junctions

Abstract

Electrical charge transport through thiophene-dithiol-based molecular wires attached to gold electrodes with three different types of crystallographic orientations (<1,1,1>, <1,1,0 > and <1,0,1 >) was investigated. Electron transport in the systems under consideration was evaluated systematically by analyzing current values, transmission spectrum, projected device density of states and zero bias orbital analysis utilizing density functional theory in conjunction with non-equilibrium Green's function. Investigations proved that tuning of conductance in nano-molecular junctions is possible through different electrode orientations. As the HOMO-LUMO gap in the <1,1,0 > oriented thiophene dithiol junction is drastically less than that of the other configurations under consideration, the <1,1,0 > configuration exhibited superior constructive conductance in comparison to other junction orientations. This provided us with ideas for designing pioneering hetero-cyclic nano-scale electronics devices. Also, <1,1,0 > has been found to show negative differential conductance behavior above +2.6 V and below -2.6 V, and hence has potential applications in oscillating and switching circuits.

Investigation of transport behavior in borospherene-based molecular wire for rectification applications

“…2, it is evident that for the 5th device and 6th device the peaks are more prominent below the Fermi level (E F ); hence the highest occupied molecular orbital (HOMO) dominates the transmission for both devices, whereas for other devices peaks are more prominent above the E F ; hence the lowest unoccupied molecular orbital (LUMO) dominates the transmission in the other four devices. The higher the value of D(E) for peaks, the greater is the involvement of that particular state in transmission and hence greater conduction [23]. For all the devices at 0 V, the molecular energy spectrum was studied.…”

Effect of crystallographic orientations on transport properties of methylthiol-terminated permethyloligosilane molecular junction

“…[34] Furthermore, the varying of electrode crystallographic orientations can result in the large variations in electronic transport properties of molecular junctions. [35][36][37][38][39][40][41][42][43][44][45] Moreover, the high and low conductance measured in alkanethiol molecular junctions are attributed to the electrode orientation, which can tune the molecule-electrode interaction. [35] For aromatic thiophene-based molecules, the (110) crystallographic orientation exhibits superior constructive conductance and negative differential conductance (NDR).…”

“…[35] For aromatic thiophene-based molecules, the (110) crystallographic orientation exhibits superior constructive conductance and negative differential conductance (NDR). [40] In particular, the NDR behavior is verified based on switching molecular junctions for utilizing the electrode orientations. [37] As the most prevalent material in integrated circuits, bulk Si can be considered as a series of cross-linked Si monatomic chains in one-dimensional structures.…”