Impact of magnetite nanoparticle incorporation on optical and electrical properties of nanocomposite LbL assemblies

Abstract

Optical and electrical properties of polyelectrolyte/iron oxide nanocomposite planar films on silicon substrates were investigated for different amount of iron oxide nanoparticles incorporated in the films. The nanocomposite assemblies prepared by the layer-by-layer assembly technique were characterized by ellipsometry, atomic force microscopy, and secondary ion mass-spectrometry. Absorption spectra of the films reveal a shift of the optical absorption edge to higher energy when the number of deposited layers decreases. Capacitance-voltage and current-voltage measurements were applied to study the electrical properties of metal-oxide-semiconductor structures prepared by thermal evaporation of gold electrodes on nanocomposite films. The capacitance-voltage measurements show that the dielectric constant of the film increases with the number of deposited layers and the fixed charge and the trapped charge densities have a negative sign.

Effect of the number of iron oxide nanoparticle layers on the magnetic properties of nanocomposite LbL assemblies

“…Due to the AFM images, the roughness of the nanocomposite coating surface is associated with the cluster formation during the nanocomposite coating growth. These results are in good agreement with previously obtained data [19][20][21]23]. Table 1 The results of AFM study of the samples (PEI(iron oxide/PAH) 6 , PEI(iron oxide/ PAH) 11 and PEI(iron oxide/PAH) 16 ).…”

“…AFM images were processed by the SPM data visualization and analysis tool Gwyddion 2.5 software in order to obtain the roughness (R a , R rms ), the thickness of composite films (d th ), the diameter of nanoparticle aggregates (D agg ), the surface concentration of nanoparticle aggregates (N agg ), and the average distance between aggregates (L agg ). From AFM measurements we found that the average roughness (R a ) values were 6.5, 6.7 and 5.9 nm (Table 1) for sample 1 (PEI/(iron oxide/ This is not typical for this type of nanocomposite layers because roughness usually increases with the growth of numbers of iron oxide layers [8,[11][12][13][14][15][16]20,21]. The different type of the dependence can be explained by lower magnitude of Z potential for iron oxide nanoparticles used in our experiments.…”

“…In contrast to the results of AFM images, the diameter of magnetic aggregates of nanoparticles D agg m calculated using the results of MFM images decreased with increasing the number of layers N. This fact can be explained taking into account only the suggestion on the different chemical composition of aggregates. The iron oxide nanoparticles can consist of a mix of magnetite and maghemite phases [21,23,29,30]. The volume fraction of maghemite increases with the growth of layer number and therefore the size of areas with higher magnetic permeability is less than the size of aggregates.…”

“…The obtained nanocomposite films were dried in air at room temperature. Deposition of multilayers on the silicon substrate was carried out by the automatic setup ''POLIION-1M'' [20,21]. The following multilayer compositions were prepared: (Sample 1) PEI/(iron oxide/PAH) 6 ; (Sample 2) PEI/(iron oxide/PAH) 11 ; (Sample 3) PEI/ (iron oxide/PAH) 16 .…”

Investigation of polymer dynamics in chitosan-maghemite nanocomposites: a potential green superparamagnetic material

“…The charge storage capacity of the superparamagnetic iron oxide nanoparticles can be drastically enhanced by increasing the active surface area [19]. Besides the superparamagnetic behaviour, iron oxide nanoparticles have been used as chemical sensors [20], MOS capacitors [21], supercapacitors [22] and electromagnetic interference shielders [23]. In general, maghemite nanoparticles are more advantages than that of magnetite nanoparticles due to their biocompatibility, chemical and thermal stability [24,25].…”