Narrow Results

This study focuses on zinc oxide by both computational and experimental methods. Pure and In-doped ZnO thin films were produced by spray pyrolysis at 300^∘C onto glass substrate. X-ray patterns reveal the polycrystalline structure according to wurtzite along the (002) direction recording a smaller grain size in nanometric scale. This aspect is confirmed by AFM scanned pictures. High transparency of thin film is observed in spite of the indium insertion into ZnO lattice which decreases it slightly. A wide bandgap exceeds 3eV of such as-grown films were recorded. Blue and orange emissions were detected as confirmed by photoluminescence analysis. Computational result analysis is used to demonstrate the ideal geometries in the ground states of pure and doped ZnO. The UV–visible absorption band shifts from 360nm to 448nm as a result of In-doping. The HUMO and LUMO diagrams demonstrate a drop in energy E as a result of doping, and the DOS profiles validate and confirm this detail. Also, the effect of indium on the linear and nonlinear optical parameters of zinc oxide was discussed.

The main objective of this paper is the realization and characterization of a new organic thin film semiconductor material through the use of an ideal mixture of Acetaminophen/Curcumin utilizing several characterization techniques. From optical analysis, we can conclude that our semiconductor material is comparable and shows good concurrency to the semiconductors applied in technologic applications. In fact, the analysis of the optical measurement (transmittance $T)$ conducting to the optical energy bandgap, $E_{\mathit{\text{g}}}$, it was found the optical bandgap is around to $2.6\pm 0.02$eV. In addition, by using the Wemple Didominico model it was found the dispersion energy E_D varied from 5eV to 7eV, the average bandgap $E_M$ separated the center of both bands occupied and unoccupied is around 4.5eV and the static refractive index $n_0$ varies from 1.3 to 2 and it dependent on the compactness and transparency of the material.

In this study, PbTe thin film was produced on glass substrates, via chemical bath deposition (CBD) method, with 3-h deposition time at 50^∘C. The produced thin film had polycrystalline structure; TeO₂, PbTe, PbTe₃ and Te₂O₅ crystals that were characterized by X-ray diffraction (XRD) had tetragonal, cubic, tetragonal and monoclinic crystal structures, respectively. Reflectivity ($R$; in %), optical transmission ($T$; in %), optical bandgap ($E_g)$, absorption, dielectric constant ($\epsilon )$, extinction coefficient ($k)$ and refractive index ($n_r)$ of polycrystalline PbTe thin film obtained using UV–Vis spectrophotometer were 29.87%, 19.41%, 3.30eV, 0.6, 3.72, 0.05 and 4.08, respectively. Grain sizes of polycrystalline PbTe thin film varied between 8.79nm and 52.55nm. Optical and electrical conductivities of the crystals according to photon energy were calculated using optical parameters, whereas their surface morphology was characterized by scanning electron microscopy (SEM). The thickness of polycrystalline PbTe thin film was measured by atomic force microscopy (AFM), and found to be 900nm.

Nanoparticle dilute magnetic semiconductors (DMS) are becoming increasingly important due to their possible applications in spintronics, an emerging field where the conduction process in the materials is a spin-based process. Nanoparticles of Mn-doped ZnO (DMS) material with general formula Zn${}_{1-x}$Mn_xO ($x=0.05,0.15,0.2$) were prepared by opting single stage combustion synthesis process. The samples characterized, exhibited formation of monophasic nanoparticles of the sample with average particle size ranging between 17 nm to 23 nm. The calculations of energy bandgap made from UV absorption spectra showed variation of the bandgap from 2.18 eV to 2.32 eV. The magnetic measurements (VSM) made on the samples confirmed formation of a single diamagnetic (Zn${}_{0.95}$Mn${}_{0.05}\mathrm{\text{O}}$) and two namely (Zn${}_{0.85}$Mn${}_{0.15}\mathrm{\text{O}}$) (Zn${}_{0.8}$Mn${}_{0.2}\text{O}$) paramagnetic samples. It is interesting to see that all the three magnetic profiles exhibit hysteresis type behavior both in diamagnetic form and paramagnetic form. The resistivity of the samples was of the order of 10${}^{10}$ Ohm-cm ($\mathrm{\Omega }$-cm) at lower temperatures. Temperature-dependent resistivity curves exhibited peaking behavior for all the three samples which is very interesting. Temperature-dependent thermo-power profiles give an indication of $n$-type semiconductor behavior with significantly deep and broad minima around 100${}^{\circ }\mathrm{\text{C}}$ which becomes sharper for sample with higher Mn concentration.

In this paper, we analyze the effects of temperature dependence of energy bandgap on $I-V$ characteristics in some carbon nanotube field effect transistors (CNTFETs) models proposed in literature in order to identify the one more suitable for computer aided design (CAD) applications. At first we consider a compact, semi-empirical model, already proposed by us, performing $I-V$ characteristic simulations at different temperatures. Our results are compared with those obtained with the Stanford-Source virtual carbon nanotube field-effect transistor model (VS-CNFET), obtaining $I-V$ characteristics comparable, but with lower CPU calculation time.

A model, correlating the reduced graphene oxide (rGO)-induced shrinking of the bandgap in rGO/TiO₂ composite films to the efficiency enhancement in associated dye-sensitized solar cells, is proposed. The intercalated rGO nanosheets into TiO₂ cause redistribution of the density of states (DOS) and modification of the energetics. The DOS increases with rGO proportion, [rGO], and the conduction band (CB) edge moves into the gap to regain the initial critical DOS for a mobility edge. The rate of electron injection from the dye increases proportionally to the DOS, thus enhancing the DSSC efficiency.

The paper presents a synthesis (solid-state. reaction) and characterization of a lead-free double perovskite oxide Ba₂(FeMo)O₆ ceramic. The initial analysis using X-ray diffraction revealed that the material has a cubic crystal symmetry with a micro-lattice strain of 0.000824 and an average crystallite size of 62nm. The microstructural features and elemental composition of the prepared polycrystalline sample were examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The SEM micrograph, EDX spectrum and elemental mapping show distinctly grown grains with well-defined grain boundaries, purity and distribution pattern of the grains, respectively. Raman scattering spectroscopy is a valuable tool for studying the vibrational modes to get information about structural and chemical properties of materials. The optical properties of the material were investigated using UV–Vis spectroscopy, which provides various parameters including energy bandgap for different technological applications. The electrical behavior of the synthesized double perovskite was examined through frequency- and temperature-dependent dielectric measurements as well as impedance spectroscopy. The electrical conduction in the material followed Jonscher’s power law and is supported by a thermally activated conduction mechanism. The analysis of electrical resistance versus temperature confirms negative temperature coefficient of resistance nature and can be used as NTC thermistors. The study of polarization-electric field loop opens up the possibility of the ferroelectric nature of the studied sample and also measures energy storage density, energy loss density and efficiency for searching different potential applications related to sensors. Overall, the results suggest its potential for various technological applications, such as in sensors and devices requiring specific electrical behavior or ferroelectric properties.