Nanostructured Fe,Co-Codoped MoO₃ Thin Films

Molybdenum oxide (MoO3) and Fe,Co-codoped MoO3 thin films obtained by spray pyrolysis have been in-depth investigated to understand the effect of Co and Fe codoping on MoO3 thin films. The effect of Fe and Co on the structural, morphological and optical properties of MoO3 thin films have been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray analysis (EDAX), optical and photoluminescence (PL) spectroscopy, and electropyroelectric methods. The XRD patterns demonstrated the formation of orthorhombic α-MoO3 by spray pyrolysis. SEM characterization has shown an increase in roughness of MoO3 thin films by Fe and Co doping. Optical reflectance and transmittance measurements have shown an increase in optical band gap with the increase in Fe and Co contents. Thermal conductivity and thermal diffusivity of Fe,Co-doped MoO3 were 24.10⁻25.86 Wm−1K−1 and 3.80 × 10−6⁻5.15 × 10−6 m2s−1, respectively. MoO3 thin films have shown PL emission. Doping MoO3 with Fe and Co increases emission in the visible range due to an increase number of chemisorbed oxygen atoms. The photodegradation of an aqueous solution of methylene blue (MB) depended on the content of the codoping elements (Fe,Co). The results showed that a degradation efficiency of 90% was observed after 60 min for MoO3: Fe 2%-Co 1%, while the degradation efficiency was about 35% for the undoped MoO3 thin film

Physical investigations on perovskite LaMnO3-δ sprayed thin films for spintronic applications

Oxygen deficient LaMnO3 thin films were successfully grown on glass substrate by spray pyrolysis at 460 °C. XRD studies show oxygen vacancies corresponding to the orthorhombic La4Mn4O11 with (040) preferential orientation. Optical properties were investigated through optical band gap and Urbach energy. The dispersion of the refractive index was discussed in terms of both Cauchy and Wemple & Di-domenico models. Raman spectroscopy shows the band positions corresponding to LaMnO3 with a shift related to oxygen deficiency. Electrical properties were quantified using impedance spectroscopy technique within frequency range of 5 Hz-13 MHz at various temperatures. Both the DC conductivity and relaxation frequency were thermally activated with activation energy around 0.9 eV. Also, AC conductivity was investigated through Jonscher law. Finally, magnetic measurements at room temperature using vibrating sample magnetometer (VSM) technique show ferromagnetic behavior of these ternary sprayed thin films. © 2015 Published by Elsevier Ltd

Impact of the Cd 2+ treatment on the electrical properties of Cu 2 ZnSnSe 4 and Cu(In,Ga)Se 2 solar cells

International audienc

Stability and morphology-dependence of Sc3+ ions incorporation and substitution kinetics within ZnO host lattice

WOS: 000361774100016In this study, sol-gel spin coating route was carried out to prepare Scandium doped ZnO thin films with different controlled percentage (1-7%). Particularly, it has been demonstrated, through original conjoint morphological-structural and optical investigations, that some interesting physical properties were induced. Indeed, X-ray diffraction (XRD) analysis shows that (002) preferential crystalline plane for Sc doped ZnO films was kept along with ZnO hexagonal wurtzite structure, although Sc doping seemed to cause a decrease in crystallinity. Except for 1 at% Sc doping ratio, optical band gap changes reversely with Urbach energy with a decrease in optical gap and a broadening of the absorption tail. Ab-initio calculations of lattice dynamical properties outlined additional strong hybridization between Sc and O atoms and show the stability of Scandium doped ZnO

Chemically grafted of single-walled carbon nanotubes onto a functionalized silicon surface

This paper highlights some interesting results regarding the Single walled carbon nanotubes (SWCNTs) functionalized by carboxylic acid, which were dispersed with ultrasonic vibration and implanted using 3 aminopropyltriethoxysilane (APTES) solution on a porous pyramidal silicon (PPS) surface. The physical characterizations of the samples were studied by both Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Also, Fourier transform infrared spectroscopy (FTIR) has been carried out. First, SEM morphological observations reveals that nano pores dig into the sides of the micro pyramids and SWCNTs located throughout the area Si pyramidal structure. Second, AFM confirm the information ob tained by various other techniques such those of electron microscopy. Third, Fourier transform infrared spectroscopy (FTIR) analysis confirms the chemical bonding between the silicon and SWCNTs. Finally, a graphical abstract is proposed to describe the implantation steps of SWCNTs on the porous silicon (pSi) having pyramidal structure

Enhancement of the photoluminescence property of hybrid structures using single-walled carbon nanotubes/pyramidal porous silicon surface

This work presents additional physical results about the enhancement of the photoluminescence property of hybrid structures using single walled carbon nanotubes/pyramidal porous silicon surface, in comparison with what has already been published on these structures in terms of synthesis conditions and FTIR investigations as reported recently by the same authors in Journal of Alloys and Compounds 694 (2017) 1036 1044. Herein, the effect of the single walled carbon nanotubes (SWCNTs) layer on the optical properties of pyramidal Porous Silicon (pPSi) in hybrid SWCNTs/pPSi structure synthetized by chemical and electrochemical etching of silicon wafer was studied. Using both scanning electron mi croscopy (SEM), SWCNTs formed a thin film on pPSi surface and they are partly embedded in its pores. An analysis of Raman spectra for the realized structures confirmed the passivation of pPSi surface by SWCNTs film. The surface bond configurations were also monitored. Moreover, SWCNTs modified Pho toluminescence (PL) spectrum of pPSi by shifting PL peaks towards high energies, showed that the defect created in the materials can result in an efficient and stabilized photoluminescence response on Silicon (Si)