Intrinsic Doping in Electrodeposited ZnS Thin Films for Application in Large-Area Optoelectronic Devices

Zinc sulphide (ZnS) thin films with both n- and p-type electrical conductivity were grown on glass/fluorine-doped tin oxide-conducting substrates from acidic and aqueous solution containing ZnSO4 and (NH4)2S2O3 by simply changing the deposition potential in a two-electrode cell configuration. After deposition, the films were characterised using various analytical techniques. X-ray diffraction analysis reveals that the materials are amorphous even after heat treatment. Optical properties (transmittance, absorbance and optical bandgap) of the films were studied. The bandgaps of the films were found to be in the range (3.68–3.86) eV depending on the growth voltage. Photoelectrochemical cell measurements show both n- and p-type electrical conductivity for the films depending on the growth voltage. Scanning electron microscopy shows material clusters on the surface with no significant change after heat treatment at different temperatures. Atomic force microscopy shows that the surface roughness of these materials remain fairly constant reducing only from 18 nm to 17 nm after heat treatment. Thickness estimation of the films was also carried out using theoretical and experimental methods. Direct current conductivity measurements on both as-deposited and annealed films show that resistivity increased after heat treatment

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

Electrosynthesis of nanoflower like-ZnS thin films and its characterizations

The thin films of ZnS have been electrodeposited onto stainless steel and ITO coated glass substrate. The films were prepared in aqueous bath, using ZnSO4 and Na2S2O3 as a precursor. The PH of bath maintained throughout the experiment is ~14. The preparative conditions are optimized to get ZnS thin films. The prepared films were further characterized for the structural, morphological and optical properties by X-ray diffraction (XRD), FT-Raman, fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscope (FE-SEM), energy dispersive spectroscopy (EDAX), atomic force microscopy (AFM), optical absorption spectroscopy, surface wettability studies, respectively. The XRD study shows the formation of ZnS phase with polycrystalline in nature. The nanoflower like morphology is observed for ZnS thin film with thickness 63 nm. FT-IR spectrum of ZnS thin film, were used to investigate the presence of organic compounds, as impurities in the ZnS films. FT-Raman shows the crystal quality and vibration properties of ZnS thin films.The water contact angle measurement shows that the ZnS thin film is hydrophilic in nature. Moreover, the optical study revealed the band gap of 3.13 eV