Investigation of the structural, optical and electrical conductivity properties of Ga-doped ZnO nanoparticles

Iron doped ZnO (Fe-ZnO) nanoparticles were synthesized using two techniques that are economical as well as scalable to yield tunable properties of nanoparticles for facilitating down conversion in an absorbing layer of a solar cell. To evaluate the suitability of Fe-ZnO nanoparticles prepared by two deposition methods, we present a comparison of optical, electrical, and structural properties of Fe-ZnO using several experimental techniques. Structural properties were analyzed using transmission electron microscopy and x-ray diffraction spectroscopy (XRD) with Rietveld analysis for extracting information on compositional variations with Fe doping. The chemical composition of nanoparticles was analyzed through X-ray photoelectron spectroscopy (XPS). The optical properties of nanoparticles were studied using photoluminescence and UV-Vis absorption spectroscopy. In addition, fluorescence lifetime measurement was also performed to study the changes in an exponential decay of lifetimes. The electrical transport properties of Fe-ZnO were analyzed by impedance spectroscopy. Our studies indicate that ethanol as a solvent in a microwave method would produce smaller nanoparticles up to the size of 11 nm. In contrast, the precipitation method produces secondary phases of Fe2O3 beyond 5% doping. In addition, our studies show that the optical and electrical properties of resulting Fe-ZnO nanoparticles depend on the particle sizes and the synthesis techniques used. These new results provide insight into the role of solvents in fabricating Fe-ZnO nanoparticles by precipitation and microwave methods for photovoltaic and other applications.

The present paper provides significant results about the impact of iron doping on the ZnO nanoparticles’ structural and electrical properties. Fe-doped ZnO (ZnO:Fe) nanoparticles with varying doping concentrations from 0 to 5% were effectively synthesized by a simple co-precipitation method. The X-ray diffraction (XRD) studies revealed that all compositions crystallize in the hexagonal wurtzite structure with the P63mc space group. They also proved the presence of a secondary phase accredited to ZnFe2O4 for ZnO:Fe 5% sample. Concerning the transmission electron microscopy, it demonstrated that the formed nanoparticles are spherical. The electrical properties were explored by complex impedance spectroscopy in the 40–107 Hz frequency range and 400–500 K temperature domains. The comparative Nyquist plots at fixed temperature 440 K suggested that the impedance value dropped with the augmentation of Fe doping concentration. Furthermore, the electrical conductivity and dielectric properties were explored as a function of frequency and temperature in the same range. The obtained results demonstrated that iron doping enhanced the AC conductivity at the same selected temperature 440 K. The analysis of the AC conductivity frequency dependence of the ZnO:Fe 1% sample was carried out by Jonscher’s universal power law and the conduction mechanism was interpreted by the overlapping-large polaron tunneling (OLPT) model. Both impedance and modulus analyses were found to display the contribution of grain and grain boundary to the electrical response of the ZnO:Fe 1% sample. Moreover, the dielectric characterization had affirmed that both dielectric constant and dielectric loss decrease with the increase in frequency and increase with the increase in temperature. These two parameters were found to augment with Fe doping. The observed properties had proven that Fe doped ZnO nanoparticles was very functional for the electric storage applications.

Microwave combustion synthesis of hexagonal prism shaped ZnO nanoparticles and effect of Cr on structural, optical and electrical properties of ZnO nanoparticles

Structural, optical and magnetic properties of ZnO nanoparticles tailored by ‘La3+’ ions

Abstract: In this work, we studied the optical properties of undoped and Zn-doped CaSnO3 nanoparticles. XRD patterns revealed the formation of the orthorhombic CaSnO3 structure, with a pronounced shift for doped samples. Fourier-transform infrared spectroscopy identified the presence of Ca-O and Sn-O vibrations. The bandgap of CaSnO3 was found to be 4.5 eV, with variations observed upon doping. Scanning electron microscopy images showed a polygonal morphology with size variations. In Zn doped Zn-doped CaSnO3, PL spectra showed a peak shift towards the visible region compared to the undoped sample. Among the Zn concentrations, 0.02M Zn-doped CaSnO3 exhibited specific capacitance of 2880 F/g, as measured from the CV curve. Keywords: Zn doped CaSnO3, Co-precipitation, Structural properties, Optical properties, Electrical properties.

Facile synthesis and tailoring the structural and photoluminescence properties of ZnO nanoparticles via annealing in air atmosphere

Effect of feedstock solution concentration on the spectroscopic and electrical transport properties of thermal plasma synthesized ZnO nanoparticles

Transparent conducting films has high properties of transmittance and conductance in the visible range. Because of its special optical and electrical properties, it is used for many application. We report in this paper our study on Aluminum -doped ZnO (AZO) thin films and three-layered thin films, in which a Ag thin film is sandwiched in between two AZO thin films. First of all, AZO thin films were deposited on glass substrates using an RF magnetron sputter deposition method. The optical and electrical properties of AZO thin films with different deposition parameters, including sputtering power, T-S distance, working pressure and oxygen pressure, were investigated. According to the above analysis the best deposition parameters of AZO thin film can be determined. And then a three-layered thin film (AZO/Ag/AZO) was grown on the glass substrate to enhance the electrical conductivity. The Ag thin film was deposited between a fixed AZO thin film (5 ~ 15 nm) using a E-Beam deposition method. The different thickness of Ag thin film were applied. All the films obtained were characterized for the electrical and optical properties. The variation of the properties with Ag film thickness was investigated. For the physical property analysis of the AZO thin films, the microstructure and roughness of the AZO thin films which had been interlayer with different Ag thickness were measured by field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM), respectively. For the optical property analysis of the AZO thin films, the transmittance and reflectivity of the AZO thin films which had been interlayer with different Ag thickness were measured by the ultraviolet-visible spectrophotometer (UV-VIS). For the electrical property analysis of the AZO thin films, the carrier concentration and the carrier mobility were measured by hall effect measurement system . In the experiment results,the FE-SEM and AFM analysis present the variation of the surface microstructure is as a function of Ag layer. In the transmittance part, the AZO thin films interlayer with Ag thickness of 10 nm is over 91.89 % of maximum transmittance in the visible part of the spectra (300 ~ 800 nm): the carrier concentration of 8.563 × 10-21 cm-3；mobility of 9.265 cm2/V-s；low resistivity of 3.71 × 10-4 Ω-cm. Due to the above results, the appropriate Ag layer can enhance the crystal structure, optics and electricity properties of AZO thin films. The AZO/Ag/AZO multilayer thin film is suitable as transparent conductive component for transparent electronics.

We have successfully investigated the structural, optical and dielectric properties of Cd assimilated SnO2 nanoparticles synthesized via very convenient precipitation route. The structural properties were studied by x-ray diffraction method (XRD) and Fourier Transform Infrared (FTIR) Spectroscopy. As-synthesized samples in the form of powder were examined for its morphology and average particle size by Transmission electron microscopy (TEM). The optical properties were studied by diffuse reflectance spectroscopy. Dielectric properties such that complex dielectric constant and ac conductivity were investigated by LCR meter. Average crystallite size calculated by XRD and average particle size obtained from TEM were found to be consistent and below 50 nm for all samples. The optical band gap of as-synthesized powder samples from absorption study was found in the range of 3.76 to 3.97 eV. The grain boundary parameters such that Rgb, Cgb and were evaluated using impedance spectroscopy.

This study investigates the synthesis and characterization of Gadolinium-doped Zirconium Sulphide (ZrS/Gd) thin films via Electrostatic Spray Deposition (ESD) for optoelectronic and photonic uses. Films were prepared at Gd concentrations of 0.01, 0.02, and 0.03 mol and evaluated for their optical, electrical, and structural properties. UV–Vis analysis showed strong absorbance between 300–400 nm, peaking at 0.75 a.u for 0.01 mol. Bandgap values, derived from Tauc plots, increased from 3.19 eV (pristine) to 3.33 eV at 0.01 and 0.03 mol, while 0.02 mol showed 3.06 eV. Optical conductivity reached ~0.75 S/m, and the refractive index peaked near 3.8 eV photon energy. Electrical measurements revealed improved conductivity from 1.65 S/m (pristine) to 1.85 S/m, with corresponding resistivity decreasing from 0.61 Ω·m to 0.54 Ω·m at increased dopant molarity and thickness. XRD analysis showed increased crystallite size and reduced dislocation density, while SEM revealed uniform surface morphology with agglomerated nanoparticles. These findings confirm that Gd doping improves optical transparency, electrical conductivity, and structural integrity of ZrS thin films, suggesting strong potential for use in UV photodetectors, multicolour LEDs, solar-blind sensors, advanced display technologies, and other optoelectronics applications.

Nano transparent conducting aluminum-doped zinc oxide (AZO) thin films were deposited on glass substrates by the magnetron sputtering technique. The thin films were characterized with X-ray diffractometer, scanning electronic microscopy, four-point probe and UV–Visible spectrophotometer. The dependence of structural, morphological, optical and electrical properties on substrate temperature was investigated. The results show that all the thin films have hexagonal wurtzite structure with highly c-axis orientation. The structural and optoelectrical properties of thin films are observed to be subjected to the substrate temperature. The AZO thin film deposited at the substrate temperature of 370 °C possesses the best optoelectronic properties, with the lowest resistivity of 6.12 × 10−4 Ω cm, the minimum microstrain of 0.92 × 10−3, the highest average visible transmittance of 85.1 % and the maximum figure of merit of 1.03 × 104 Ω−1 cm−1. The optical bandgap of thin films was estimated from Tauc’s relation and observed to be an increasing tendency with the increment of the substrate temperature. Furthermore, the optical constants such as refractive index, extinction coefficient, dielectric constant, dissipation factor and optical conductivity were determined by the pointwise unconstrained optimization method, and the dispersion behaviour was studied by the Wemple–DiDomenico single-oscillator model.

Zinc oxide (ZnO) has gained great interest for two decades, and its structural, optical, and electrical properties have been investigated by scientists for technological applications. The optical properties of ZnO provide an opportunity for its application in solar cells, lasers, and light-emitting diodes. We prepared ZnO thin films with various In doping levels by using a spin coating technique, and characterised their morphological and detailed optical properties for optical applications. According to the morphological properties obtained by atomic force microscopy, the film surfaces are homogeneous and the In doping level affects the surface morphology of the films. The optical properties of the films were investigated using an ultraviolet–visible spectrometer, and some optical parameters such as band gap, refractive index, extinction coefficient, single oscillator parameters, real and imaginary functions of the dielectric coefficient, and optical conductivity were calculated and discussed in detail. The various In doping levels affected the optical properties, and the In-doped ZnO thin films can find applications in industry.

Mixed-phased InxSey thin film containing InSe, In2Se3 and In6Se7 phases was prepared by M-CBD method and characterized by X-ray diffraction, AFM, optical spectroscopy and J-V measurements. Structural, optical and electrical conductance properties were modified by annealing the films at different temperatures. Optical and morphological properties were also investigated dependently on temperature and concentration of cationic precursor solution. It has been observed with annealing that, the compositions of the phases changed, particle sizes increased, energy band gaps decreased and electrical conductivity increased. The photoconductivity of thin film was revealed by J-V measurements and slightly increased by annealing. From temperature-dependent J-V measurements, activation energies (Ea) were calculated in low and high temperature regions and, found to be 0.03 eV for low temperature region and 0.8 eV for high temperature one.

We have prepared a series of double perovskites La2−xYxNiMnO6 (x = 0.0, 0.5, 1.0, 1.5, 2.0 mol%) by sol-gel method. The structural, optical and transport properties of La2−xYxNiMnO6 have been characterized by x-ray diffraction (XRD), Fourier transform infrared (FTIR) and ultra-violet (UV) visible spectroscopy at room temperature whereas dielectric and electrical properties are calibrated in the temperature range of 293–473 K. The structural properties are discussed by rietveld refinement (JANA software) which gives monoclinic structure with space group P21/n for all series. FT-IR measurements give IR spectra which are fitted by using Lorentz oscillator model, optical conductivity, oscillator strength and damping factors. UV-visible spectroscopy gives optical band gaps, indicating the semiconducting behavior of observed series. The transport characteristics of La2−xYxNiMnO6 have been found by dielectric and electrical measurements. The dielectric constant, tangent losses and ac conductivities as function of frequency and temperature have been discussed in detail. The activation energies are calculated by Arrhenius plot which inveterate the semiconducting nature of all samples. It has been further confirmed that there is small polaron hopping (SPH) conduction mechanism in all samples.

Effect of crystalline structure on optical and electrical properties of IWOH films fabricated by low-damage reactive plasma deposition at room temperature