Thierno Sall

Synthesis of In2S3 thin films by spray pyrolysis from precursors with different (S)/(In) ratios

Indium sulfide (In2S3) thin films were prepared by chemical spray pyrolysis technique from solutions with different [S]/[In] ratios on glass substrates at a constant temperature of 250 °C. Thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS), Raman spectroscopy and optical transmittance spectroscopy. All samples exhibit a polycrystalline structure with a preferential orientation along (0, 0, 12). A good stoichiometry was attained for all samples. The morphology of thin film surfaces, as seen by SEM, was dense and no cracks or pinholes were observed. Raman spectroscopy analysis shows active modes belonging to β-ln2S3 phase. The optical transmittance in the visible range is higher than 60% and the band gap energy slightly increases with the sulfur to indium ratio, attaining a value of 2.63 eV for [S]/[In] = 4.5.

Elaboration and characterization of In 2 S 3 thin films by spray pyrolysis with [S]/ [In] = 3 ratio

In2S3 thin films were elaborated onto glass substrate by spray pyrolysis method using sulphur-to-indium ratio ([S]/[In]) of 3 and different substrate temperatures. The as-deposited and annealing films were characterized by X-Ray Diffraction (XRD) for the structural, Energy Dispersive Spectroscopy (EDS) for the composition, Raman spectroscopy for samples quality and optical transmittance to measure gap energy. XRD revealed a β-In2S3 phase with a preferential orientation along (0 0 12) plane. Good stoichiometry was noticed in EDS measurement. Raman spectroscopy analysis shows a prominent of active modes of β-In2S3 films with annealing. This is confirming an improvement of structure cristallinity of all films and optical analysis shows a decrease of gap energy after annealing.

β-In 2 S 3 thin films doped by tin (Sn 4+ ) and deposited by Chemical Spray Pyrolysis technique for photovoltaic applications

β-In2S3 thin films doped by tin at different percentages were deposited by Chemical Spray Pyrolysis (CSP) method at 300 °C substrate temperature onto glass substrate. X-ray diffraction (XRD) was used to study structure, Raman spectroscopy analysis for phase, quality and structure, Scanning Electron Microscopy (SEM) for the surface morphology, Energy Dispersive X-Ray Spectroscopy (EDS) for the composition, Atomic Force Microscopy (AFM) for surface topography and transmittance to determine the gap energy. The XRD analysis showed that the crystallographic structure of β-In2S3 is present on the deposited films with a preferential orientation along (0 0 12) and no secondary phase is observed. SEM images presented films well covered without crack and pinholes but different morphologies and AFM micrographs showed very compact films when the percentage of doping increased. Main mode at 327cm-1 is showed by Raman spectroscopy and from optical analysis, the transmission varied from 60% to 70% with band gaps estimated from 2.64 to 2.82 eV.

Growth and characterization of β-In 2 S 3 thin films prepared by chemical spray pyrolysis technique with and without alcoholic solution

Beta indium sulfide (β-In2S3) thin films were deposited by Chemical Spray Pyrolysis technique, a fast, cost effective and vacuum free method with alcoholic and aqueous solution using InCl3 and thiourea as source of indium and sulfur respectively. All films were deposited onto glass substrate with different temperatures. Characterization of the films was carried out by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Atomic Force Microscopy (AFM) and optical transmission. The structural analysis reveals films with (0 0 12) as main peak for all samples in all case. (107) peak appeared only in films deposited without alcohol with high intensity at 300°C substrate temperature. SEM images shows films dense, continuous, compact and homogeneous without void but one noted cracks in films prepared from aqueous solution. EDS tables show the presence of sulfur and indium in all samples with good stoichiometry. AFM micrographs reveal rough films and variation of grains size. Optical analysis to determine band gap gives band gap varying from 2.54eV to 2.81eV for samples deposited from aqueous solution and band gap between 2.70eV to 2.89eV for samples prepared from alcoholic solution.