Low Temperature Conductance Measurements of Self‐Assembled Monolayers of 1,4‐Phenylene Diisocyanide

Abstract

A monolayer sandwich. Electron‐transport measurements were carried out in self‐assembled monolayers of 1,4‐phenylene diisocyanide using two different approaches; in one of the approaches, a single monolayer was sandwiched between two small gold contacts by use of nanolithographical and evaporation techniques (see picture). Conductance measurements at low temperature show discrete structures for both types of samples which are interpreted as arising from quantum transport through molecular ensembles.

Electronic transport calculations for self-assembled monolayers of 1,4-phenylene diisocyanide on Au(111) contacts

“…Only recently, sandwiched SAM devices at 4.2K were studied, 9,14 where a benzene ring with two cyanide instead of thiol end-groups was used. The measurements exhibited currents of the order of 50 − 400nA.…”

“…Low temperature experiments with PDI SAM's sandwiched between two metallic leads show several peaks in the CV -diagram. 9,14 The typical voltage differences of these peaks are in the range of ∆U ≈ 0.2V (i.e. there are about 5 peaks within U = 0V and U = 1V).…”

“…In this paper we study the way in which changing the geometrical alignment of the mono-layer has an influence on the conduction properties of a molecular device. In so doing we can rule out a number of explanations which have previously been considered 9 to explain the occurrence of additional structure in the conductance-voltage (CV ) characteristics.…”

Influence of the Anchor Group on Charge Transport through Single‐Molecule Junctions

“…Calculations based on density functional theory (DFT) yielded promising results [10,13,14] for isocyanide-linked molecules in terms of absolute conductance compared with thiol-linked ones. Previous experimental work reports on transport measurements through self-assembled monolayers (SAM), embedded between metallic electrodes [11,15,16,17] or contacted using scanning probe techniques. [18] Herein, we have systematically studied the influence of the chemical nature of the molecule-metal contact on the chargetransport properties of single-molecule junctions using two different anchor groups, namely, thiol (-SH) and isocyano (-NC) groups.…”

Coulomb blockade phenomena in electromigration break junctions

“…Although it is currently not possible to fabricate such small junctions reliably on a large scale, various experimental approaches have been followed to gain a first insight into the electrical behavior of small molecular structures. Towards this end, scanning probe methods, [2][3][4] sandwich junctions, 5,6 as well as break-junctions created through mechanical 7,8 or electromigration-induced [9][10][11][12] breaking of metallic nanowires have been employed to contact a small number of organic molecules and investigate their electrical properties.…”