Optical and Thermal Properties of In2S3

Photothermal deflection spectroscopy (PDS) is carried out in order to investigate thermal and optical properties of Al doped In2S3. The influence of thermal annealing on its gap energy as well as its thermal properties is revealed. In this way, we notice that thermal conductivity is increased and the gap energy is reduced. These features are probably due to the improvement of the crystalline structure of the sample

Effect of spray solution flow rate on the physical properties of CuInS

CuInS2 thin films have been successfully prepared on Pyrex substrates using spray pyrolysis technique. In this work, we study the effect of the flow rate on the physical properties of CuInS2 thin films. X-ray diffraction pattern reveals the presence of tetragonal structure with (1 1 2) preferential orientation for CIS thin layers. Optical analysis by means of transmission T(λ) and reflection R(λ) measurements allows to determine the direct band gap energy value in the order of 1.44 eV, indicating that CuInS2 compound has absorbing properties favorable for applications in solar cell devices. Photoluminescence measurements are performed on CuInS2 crystals and the analysis reveals that the emission is mainly due to donor-acceptor pair transitions

Improvement of ozone sensing parameters by CuO–SnO2: F mixed oxide sprayed thin films

International audienceIn this current work, CuO–SnO2: F mixed oxide thin films were synthesized by spray pyrolysis technique on glass substrates. The structural and optical properties were optimized and improved by varying the substrate temperature from 300 to 350 °C by a step of 25 °C. By increasing the substrate temperature, in addition to the CuO monoclinic phase we notice the appearance of the SnO2: F tetragonal phase in the XRD spectrum. Therefore, CuO–SnO2: F coupled oxide thin film, where the ratio in the spray solution (r=3) was successfully grown at the elevated temperature equals to 350 °C. This result was confirmed by Raman and FTIR analyses. SEM analysis of CuO–SnO2: F films elaborated at a substrate temperature equal to 350 °C endorsed the particle-like spherical shape structure with smooth surface. While EDS and Elemental mapping confirmed the presence of the expected elements. By using the transmission reflection spectra, we estimated the values of the refractive index n, the extinction coefficient k and the dielectric constant. In the visible area the refractive index (n) varies from 1.5 to 2.3 and the extinction coefficient k decreases from 0.8 for Ts = 300 °C, up to about 0.2 for Ts = 350 °C. Moreover, the photoluminescence spectra of the films was investigated and interpreted. The gas-sensing measurements revealed that CuO–SnO2: F thin films grown by spray-pyrolysis method at the substrate temperature equals to 350 °C, can detect minuscule traces of O3 gas (30 ppb) with good sensitivity, fast response and recovery times (60 s and 79 s respectively), at relatively low temperature (200 °C). This manuscript reports the effectiveness of our homemade device as promoter ozone gas sensor in many industrial applications

Synthesis and Characterization of MgO Thin Films Obtained by Spray Technique for Optoelectronic Applications

Magnesium oxide (MgO) thin films with different magnesium concentrations ([Mg2+] = 0.05, 0.1, 0.15 and 0.2 mol·L−1) in a spray solution have been successfully grown using a spray pyrolysis technique. X-ray diffraction (XRD), Maud software, FTIR spectroscopy, a confocal microscope, Wien2k software, spectrophotometry and a Photoluminescence spectrometer were used to investigate the structural, morphological and optical properties. XRD analysis revealed a better crystalline quality of the MgO thin layer synthesized with [Mg2+] = 0.15 mol·L−1, which crystallized into a face-centered cubic structure along the preferred orientation (200) lattice plan. The enhancement of the crystalline quality for the MgO thin film ([Mg2+] = 0.15 mol·L−1) was obtained, which was accompanied by an increment of 94.3 nm of the crystallite size. No secondary phase was detected and the purity phase of the MgO thin film was confirmed using Maud software. From the transmission spectra results, high transparent and antireflective properties of the MgO thin film were observed, with an average transmission value of about 91.48% in the visible range, which can be used as an optical window or buffer layer in solar cell applications. The films also have a high reflectance value in the IR range, which indicates that the highly reflective surface will prevent an increase in surface temperature under solar irradiation, which could be beneficial in solar cell applications. A direct band gap type was estimated using the Tauc relation which is close to the experimental value of 4.0 eV for optimal growth. The MgO material was tested for the degradation of methylene blue (MB), which reached a high photodegradation rate of about 83% after 180 min under sunlight illumination. These experimental trends open a new door for promising the removal of water contaminants for photocatalysis application

Etude de l'usinage par faisceau laser continu et impulsionnel (enlevement de matiere sans outil de coupe)

Available from INIST (FR), Document Supply Service, under shelf-number : AR 16241 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEMinistere de l'Enseignement Superieur et de la Recherche, 75 - Paris (France)FRFranc