Characterization of 10,12-pentacosadiynoic acid Langmuir–Blodgett monolayers and their use in metal–insulator–metal tunnel devices

Abstract

SummaryThe characterization of Langmuir–Blodgett thin films of 10,12-pentacosadiynoic acid (PDA) and their use in metal–insulator–metal (MIM) devices were studied. The Langmuir monolayer behavior of the PDA film was studied at the air/water interface using surface tension–area isotherms of polymeric and monomeric PDA. Langmuir–Blodgett (LB, vertical deposition) and Langmuir–Schaefer (LS, horizontal deposition) techniques were used to deposit the PDA film on various substrates (glass, quartz, silicon, and nickel-coated film on glass). The electrochemical, electrical and optical properties of the LB and LS PDA films were studied using cyclic voltammetry, current–voltage characteristics (I–V), and UV–vis and FTIR spectroscopies. Atomic force microscopy measurements were performed in order to analyze the surface morphology and roughness of the films. A MIM tunnel diode was fabricated using a PDA monolayer assembly as the insulating barrier, which was sandwiched between two nickel layers. The precise control of the thickness of the insulating monolayers proved critical for electron tunneling to take place in the MIM structure. The current–voltage characteristics of the MIM diode revealed tunneling behavior in the fabricated Ni–PDA LB film–Ni structures.

Study of Polydiacetylene-Poly (Ethylene Oxide) Electrospun Fibers Used as Biosensors

“…Similar features were observed in the spectrum B of the red PEO-PDA fibers: IR ν max cm −1 : 2919 cm −1 (H-C=C), 2885-2857 cm −1 (H-C-H), 1722 cm −1 (C=O, ester), and 1107 cm −1 (C-O). The resulting resonance features were similar to previously reported results for the PDAs [ 27 , 28 ].…”

Relationship between structure and molecular interactions in monolayers of specially designed aminolipids

“…Moreover, a panoply of other fundamental questions is stimulating the research on two-dimensional (2D) polymers for revealing their mechanical, electrical or magnetic properties, given the fact that such cross-linked nanosheets can have sizes of several square centimeters while still representing one single macromolecule. 29 More applied directions concern their use as protective layers for electronic devices, 30,31 'anti-fouling' surfaces which hinder protein adsorption, 32 surface-assisted self-assembly strategies leading to the growth of nanostructures, 33 or surfaces with super-wettability. 34 Lipid monolayers with tailored, cross-linkable headgroups, as investigated here, can thus be considered promising building blocks for the functionalization of gas/liquid and liquid/liquid interfaces leading to dened mechanical properties, in terms of bending-, shear-, and surface-dilational elasticity, as well as transport properties.…”

Fabrication and Characterization of ZnO Langmuir–Blodgett Film and Its Use in Metal–Insulator–Metal Tunnel Diode

“…Sharma et al characterized and explored the use of a polymerized 10,12-pentacosadiynoic acid LB monolayer as the insulator layer in the MIM diode. 19 Ram et al used the LB deposition technique to fabricate a polyaniline thin film as the insulator layer between silver and an ITO glass plate that exhibited nonlinear rectification. 20 The use of conductive LB films of bis(ethylenedioxy)tetrathiafulvalene as the top electrode of the MIM structure was studied by Mochizuki et al 21 Iwamoto fabricated MIM tunnel diodes using polyimide LB films and studied their electrical properties over a range of temperature; 22 however, the thin LB organic films could be easily damaged during the top metal deposition resulting in short circuited devices.…”

“…20 The use of conductive LB films of bis(ethylenedioxy)tetrathiafulvalene as the top electrode of the MIM structure was studied by Mochizuki et al 21 Iwamoto fabricated MIM tunnel diodes using polyimide LB films and studied their electrical properties over a range of temperature; 22 however, the thin LB organic films could be easily damaged during the top metal deposition resulting in short circuited devices. 19 In this work, ZnO has been used as an insulating layer in the MIM structure. Gupta et al demonstrated ZnO as an insulating material in a MIM structure and presented capacitance−voltage (C−V) and conductance− voltage (G−V) measurements of that structure.…”

“…The deposition parameters were determined from the transfer ratio, which is the ratio of the decreased area at the subphase surface during deposition to the total substrate area. 19 The feedback control system of the barrier compression of the trough assures a closely packed monolayer at the air−subphase surface. Subsequently, the substrate was dipped into the subphase, maintaining all deposition parameters, to transfer the monolayer from the air-subphase interface to the surface of the subphase.…”