Annealing study and thermal investigation on bismuth sulfide thin films prepared by chemical bath deposition in basic medium

This is a post-peer-review, pre-copyedit version of an article published in Applied Physics A 124.2 (2018): 166. The final authenticated version is available online at: http://doi.org/10.1007/s00339-018-1584-7Bismuth sulfide thin films were prepared by chemical bath deposition using thiourea as sulfide ion source in basic medium. First, the effects of both the deposition parameters on films growth as well as the annealing effect under argon and sulfur atmosphere on as-deposited thin films were studied. The parameters were found to be influential using the Doehlert matrix experimental design methodology. Ranges for a maximum surface mass of films (3 mg cm-2) were determined. A well crystallized major phase of bismuth sulfide with stoichiometric composition was achieved at 190°C for 3 hours. The prepared thin films were characterized using Grazing Incidence X-ray diffraction (GIXRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDX). Second, the band gap energy value was found to be 1.5 eV. Finally, the thermal properties have been studied for the first time by means of the electropyroelectric (EPE) technique. Indeed, the thermal conductivity varied in the range of 1.20 - 0.60 W m-1 K-1 while the thermal diffusivity values increased in terms of the annealing effect ranging from 1.8 to 3.5 10-7 m2s-1This work was financially supported by the Tunisian Ministry of Higher Education and Scientific Research and by the WINCOST (ENE2016-80788-C5-2-R) project funded by the Spanish Ministry of Economy and Competitivenes

Cobalt oxide thin films prepared by metalorganic chemical vapor deposition from cobalt acetylacetonate

Thin films of cobalt oxide have been deposited on various substrates, such as glass, Si(100), SrTiO3(100), and LaAlO3(100), by low pressure metalorganic chemical vapor deposition (MOCVD) using cobalt(IL), acetylacetonate as the precursor. Films obtained in the temperature range 400-600 degreesC were uniform and highly crystalline having Co3O4 phase as revealed by x-ray diffraction. Under similar conditions of growth, highly oriented thin films of cobalt oxide grow on SrTiO3(100) and LaAlO3(100). The microstructure and the surface morphology of cobalt oxide films on glass, Si(100) and single crystalline substrates, SrTiO3(100) and LaAlO3(100) were studied by scanning electron microscopy. Optical properties of the films were studied by uv-visible-near IR spectrophotometry

Epitaxial growth of Co3O4Co_3O_4 films by low temperature, low pressure chemical vapor deposition

The growth of strongly oriented or epitaxial thin films of metal oxides generally requires relatively high growth temperatures or infusion of energy to the growth surface through means such as ion bombardment. We have grown high quality epitaxial thin films of $Co_3O_4$ on different substrates at a temperature as low as 450° C by low pressure metal organic chemical vapor deposition (MOCVD) using cobalt(II) acetylacetonate as the precursor. With oxygen as the reactant gas, polycrystalline $Co_3O_4$ films are formed on glass and Si(100) in the temperature range 350 550° C. Under similar conditions of growth, highly oriented films of $Co_3O_4$ are formed on $SrTiO_3(100)$ and $LaAlO_3(100)$. The film on $LaAlO_3(100)$ grown at 450° C show a rocking curve FWHM of 1.61°, which reduces to 1.32° when it is annealed in oxygen at 725° C. The film on $SrTiO_3(100)$ has a FWHM of 0.33° (as deposited) and 0.29° (after annealing at 725° C). The φ-scan analysis shows cube on cube epitaxy on both these substrates. The quality of epitaxy on $SrTiO_3$ (100) is comparable to the best of the perovskite basedoxide thin films grown at significantly higher temperature