Hicham Bakkali

Universidad de Cádiz | UCA · Department of Material Science and Metallurgy Engineering and Inorganic Chemistry

Carbon fibre reinforced polymers (CRFP) are extensively used in many industrial applications thanks to its mechanical properties and its low weight. Nevertheless, the orthotropic character of CRFP highly reduces its applications. The transversal electrical conductivity in CRFP is two orders poorer than in the longitudinal direction. To improve thei...

Vanadium dioxide (VO2) is widely recognized as a thermochromic material with great potential for application in smart glazing for energy-efficient buildings. The monoclinic (M1) VO2 phase undergoes a first-order reversible phase transition from the semiconductor to the rutile metallic state. In this study, an M1 VO2 porous film was synthesized via...

Au/0.8 nm–GaN/n–GaAs Schottky diodes were manufactured and electrically characterized over a wide temperature range. As a result, the reverse current Iinv increments from 1 × 10−7 A at 80 K to about 1 × 10−5 A at 420 K. The ideality factor n shows low values, decreasing from 2 at 80 K to 1.01 at 420 K. The barrier height qϕb grows abnormally from 0...

This work is dedicated to the study of structural, morphological, and optical properties of stable isoindole derivative, which keeps o-quinoid structure. Corresponding properties were studied using X-ray diffraction, SEM, and UV-Vis methods. The geometry of the target molecule was optimized using the M06-2x/cc-pVTZ method. Theoretical UV-Vis spectr...

This research paper reports on spray pyrolysis deposited cerium dioxide (CeO2) thin films. study consists of investigating the effect of Vanadium (V) doping on structural and optical characteristics of Ce1−xVxO2(0.02≤x≤0.06) layers using several characterization techniques. Indeed, X-ray diffraction patterns helped to estimate the crystallite size...

In this work, we have studied the dibenzofluorene derivative belonging to the KuQuinones family. We have investigated the structural, morphological and optical properties of this derivative, which is part of the new sub-class of dibenzofluorenes, due to its existence as a zwitterion, in contrast to other KuQuinones. The optimization of the dibenzof...

Large contact resistance at metal-substrate/ZnO heterostructure interfaces prevents achieving highly efficient device performance. Herein, we present a systematic study on the effect of Ni-doping in the reduction of the Schottky contact barrier at metal-substrate/ZnO heterostructure. To this end, Ni-doped zinc oxide (Ni:ZnO) thin films were deposit...

We report on the electronic and optical properties of ultrathin granular films. We demonstrate that the static dielectric constant increases with thickness in the dielectric regime and diverges at the critical thickness, as predicted by classical percolation theory. However, for thicker samples, the dc conductivity does not obey scaling laws due to...

Growing ultrathin nanogranular (NG) metallic films with continuously varying thickness is of great interest for studying regions of criticality and scaling behaviors in the vicinity of quantum phase transitions. In the present work, an ultrathin gold plasmonic NG film was grown on a sapphire substrate by RF magnetron sputtering with an intentional...

In this work, we have grown nanostructured vanadium dioxide (VO2) thin films by a spray pyrolysis coating method on glass pre-heated substrates at 450 °C and studied their optical and electronic properties. As-prepared film structure and morphology, with a thickness of ~ 400 nm, were examined by X-ray diffraction, Raman spectra, and atomic force mi...

Carbon Fiber Reinforce Polymer (CFRP) are much stiffer than aerospace metallic alloys, on the other side, they have highly limited electrical and thermal conductivity. These features reduce their strength to lightnings impact, which is a strong problem for aerospace industry. The here proposed approach is to cover the carbon fibers with highly boro...

We present an ellipsometric analysis to model the order-disorder transition in nano-granular gold embedded in a silica matrix (Au-SiO2). The optical measurements were performed by means of Reflection Spectroscopic Ellipsometry (RSE) over the spectral wavelength range 300–2500 nm. Upon thermal annealing of Au-SiO2 in the temperature range of 200 to...

The optical response of different types of multilayered nanostructures was studied by means of spectroscopic ellipsometry. A variable angle spectroscopic rotating analyzer ellipsometer, J.A. Woollam V-VASE, was used to measure the ellipsometric angles, amplitude ratio (Ψ) and phase differences (Δ) between the reflected polarized light p and s compo...

Discontinuous multilayer (DML) thin films, which consist of nano-granular metals (NGMs) embedded in a dielectric matrix, have attracted significant interest as engineered plasmonic metamaterials. In this study, a systematic layer-by-layer deposition of three-dimensional sub-wavelength periodic plasmonic DML structures via the radio frequency sputte...

We report on the optical properties in the dielectric regime of gold nanostructured granular metal thin films fabricated through sputter deposition with a composite target at room temperature and over a wide photon energy range (0.62–4.13 eV) by means of Spectroscopic Ellipsometry. The thickness and the films effective optical constants are success...

The universality of the ac electrical transport in granular metals has been scarcely studied and the actual mechanisms involved in the scaling laws are not well understood. Previous works have reported on the scaling of capacitance and dielectric loss at different temperatures in Co-ZrO2 granular metals. However, the characteristic frequency used t...

The ac response in the dielectric regime of thin films consisting of Pd nanoparticles embedded in a ZrO2 insulating matrix, fabricated by co-sputtering, was obtained from impedance spectroscopy measurements (11 Hz–2 MHz) in the temperature range 30–290 K. The response was fitted to an equivalent circuit model whose parameters were evaluated assumin...

The tunneling differential conductance of Pd-ZrO2 thin granular films prepared by RF sputtering has been measured. We found that the temperature dependence of $G(V,T)$ at zero bias $[G(0,T)\propto \exp(-\sqrt{\frac{U}{k_BT}\,})]$ reveals the presence of thermally assisted tunneling. The dependence of differential conductance on applied voltage show...