Cadmium sulfide thin films growth by chemical bath deposition

Cadmium sulfide (CdS) thin films have been prepared by a simple technique such as chemical bath deposition (CBD).A set of samples CdS were deposited on glass substrates by varying the bath temperature from 55 to 75 ℃ at fixed deposition time (25 min) in order to investigate the effect of deposition temperature on CdS films physical properties.The determination of growth activation energy suggests that at low temperature CdS film growth is governed by the release of Cd2+ ions in the solution.The structural characterization indicated that the CdS films structure is cubic or hexagonal with preferential orientation along the direction (111) or (002),respectively.The optical characterization indicated that the films have a fairly high transparency,which varies between 55％ and 80％ in the visible range of the optical spectrum,the refractive index varies from 1.85 to 2.5 and the optical gap value of which can reach 2.2 eV.It can be suggested that these properties make these films perfectly suitable for their use as window film in thin films based solar cells.     

Effect of Annealing on the Dark and Illuminated I(V ) Characterization of a ZnO:Ga|Cu2O Hetero-Junction Prepared by Ultrasonic Spray System

Semiconductors - This paper presents the Ultrasonic Spray Pyrolysis system fabrication of gallium-doped zinc oxide (ZnO:Ga)|cuprous oxide (Cu2O) thin film hetero-junction. The deposition parameters...     

Electrical properties of Cu4ZnSnS2/ZnS heterojunction prepared by ultrasonic spray pyrolysis

Cu₂ZnSnS₄ (CZTS)/ZnS heterojunctions have been prepared by a successive deposition of ZnS and CZTS thin films by ultrasonic spray pyrolysis technique on glass substrates. The cupric chloride concentration has been varied in the starting solution in order to investigate its influence on device properties. CZTS/ZnS heterojunctions were characterized by recording their current-voltage characteristics at different temperatures. The obtained results exhibit a good rectifying behavior of the realized heterojunction. Analysis of these results yields saturation current, series resistance and ideality factor determination. From the activation energy of saturation current we inferred that the thermal emission through the barrier height is the dominant mechanism of the reverse current rather than the defects contribution.     

ITO substrate resistivity effect on the properties of CuInSe<Subscript>2</Subscript> deposited using two-electrode system

The purpose of this work is to deposit the CuInSe₂ films on the ITO substrate by electrodeposition technique using a simplified two electrodes system and to investigate the effect of ITO sheet resistance on the fundamental properties of the resulting films. The as deposited films were annealed under argon atmosphere at 300 °C during 30 min. The structural, morphological and electrical properties were characterized respectively by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrical resistivity measurements. The optical band gap of samples was estimated using the optical absorption technique. After annealing, the XRD spectra show diffraction peaks corresponding to the single-phase chalcopyrite CuInSe₂ with (112) as main reflection. The SEM images reveal a homogeneous surface and the estimated grain size was calculated from Scherrer’s Equation with (112) peak lay in the range of 165–272 Å. The band gap, E _g, is a decreasing function with the ITO sheet resistance.     

Correlation between the structural, morphological, optical, and electrical properties of In2O3 thin films obtained by an ultrasonic spray CVD process

Indium oxide (In₂O₃) thin films are successfully deposited on glass substrate at different deposition times by an ultrasonic spray technique using Indium chloride as the precursor solution; the physical properties of these films are characterized by XRD, SEM, and UV-visible. XRD analysis showed that the films are polycrystalline in nature having a cubic crystal structure and symmetry space group Ia3 with a preferred grain orientation along the (222) plane when the deposition time changes from 4 to 10 min, but when the deposition time equals 13 min we found that the majority of grains preferred the (400) plane. The surface morphology of the In₂O₃ thin films revealed that the shape of grains changes with the change of the preferential growth orientation. The transmittance improvement of In₂O₃ films was closely related to the good crystalline quality of the films. The optical gap energy is found to increase from 3.46 to 3.79 eV with the increasing of deposition time from 4 to 13 min. The film thickness was varied between 395 and 725 nm. The film grown at 13 min is found to exhibit low resistivity (10^-2 Ω·cm), and relatively high transmittance (~ 93%).     

Acetylacetone phenylhydrazone functionalized polyurethane foam: Determination of copper,zinc and manganese in environmental samples and pharmaceutics using flame atomic absorption spectrometry

In the present work, acetylacetone phenylhydrazone (AAPH) was chemically anchored to polyurethane foam (PUF) via azo coupling of the toluidine NH₂ in PUF to active CH₂ in acetylacetone (AA) and further reaction to phenylhydrazine to give new solid phase extraction (SPE) sorbent for determination of Cu(II), Zn(II) and Mn(II) in natural and pharmaceutical samples. The AAPH–PUF was characterized by UV–VIS, IR, H¹ NMR, elemental and TGA analysis. Optimal experimental conditions were at pH 5–6, shaking time 20 min, sample flow rate 1.0 mL min^?1, and desorption by 10 mL from 0.5 mol L^?1 hydrochloric acid. The limit of detection (3σ) was found to be 0.10, 0.12 and 0.19 μg L^?1 for Cu(II), Zn(II) and Mn(II), respectively. A preconcentration factor of 100 has been achieved for all elements. Precision (RSD%) was found to be 6.3%, 5.3% and 3.2% (n = 5), respectively. Successful application was achieved for environmental samples (tap water, olive leaves, and fish liver) and pharmaceutical formulation. The obtained recovery varied between 90.8% and 96.8% and RSD was under 6.7%.     

In doped ZnO thin films

ZnO thin films were deposited by ultrasonic spray technique, zinc acetate was used as starting solution with a molarity of 0.1 M. A set of indium (In) doped ZnO (between 2 and 8 wt%) thin films were grown on glass substrate at 350 °C. The present work is focused on the influence of the doping level on the structural, optical and electrical films properties. Optical film characterization was carried by using UV-visible transmission spectroscopy, the optical gap was deduced from absorption. From X ray diffraction (XRD) analysis, we have deduced that ZnO films are formed with nanocrystalline structure with preferential (0 0 2) orientation. The grain size is increased with In doping from 28 to 37 nm. Electrical characterization was achieved using two-probes coplanar structure, the measured conductivity varies from 2.3 to 5.9 Ω cm⁻¹ when increasing the doping level. However the optical gap is reduced from 3.4 to 3.1 eV.     

Modeling the nanoindentation of elastoplastic materials with nonlinear adaptive springs (NASs)

In this paper, the /spl beta/-material concept helps to elaborate and explore a new model for the indentation cycle of elastoplastic materials. The proposed approach takes into account the nonlinear behavior of homogeneous and isotropic materials. It uses the idea of a nonlinear adaptive spring (NAS) with changing properties according to the depth of penetration to accurately reproduce the material behavior in loading and unloading stages. The properties of the adopted NAS are included in its own stiffness function /spl kappa/ appearing in the form of an infinite sum of which the convergence and some properties are discussed in detail. This new model, which allows the indentation cycle to be reproduced whatever the penetration depth, permits at the same time a direct calculation of the involved energy terms. It also provides the possibility to perform separate analysis of the plastic energy, which allows distinguishing between different types of the material behavior and a better understanding of its nature. A validation is accomplished by applying the method to three different materials.     

Study of glass formation in the Sb2O3-PbO-MnO ternary system

Vitreous systems based on antimony oxide Sb₂O₃ have been investigated. The influence of MnO substitution on the mechanical and physical properties in the (80 − x)Sb₂O₃-20PbO-xMnO and (70 − x)Sb₂O₃-(30 − x)PbO-2xMnO systems has been studied. Vickers hardness, density, molar volume, Young modulus, glass temperature transition, infrared and UV transmission spectra depend on the MnO concentration. Crack analysis of the glass surface under indentor deformation shows the tenacity changes according to concentration of the MnO.     

Properties of n-type SnO2 semiconductor prepared by spray ultrasonic technique for photovoltaic applications

Transparent conducting n-type SnO₂ semiconductor films were fabricated by employing an inexpensive, simplified spray ultrasonic technique using an ultrasonic generator at deferent substrate temperatures(300, 350, 400, 450 and 500℃). The structural studies reveal that the SnO₂ films are polycrystalline at 350, 400, 450, 500℃ with preferential orientation along the(200) and(101) planes, and amorphous at 300℃. The crystallite size of the films was found to be in the range of 20.9-72.2 nm. The optical transmittance in the visible range and the optical band gap are 80% and 3.9 eV respectively. The films thicknesses were varied between 466 and 1840 nm. The resistivity was found between 1.6 and 4×10^-2 Ω·cm. This simplified ultrasonic spray technique may be considered as a promising alternative to a conventional spray for the massive production of economic SnO₂ films for solar cells, sensors and opto-electronic applications.