Iron Sulfide Thin Films Research Articles

Structural, Morphological and Optical Study of Manganese Doped FeS (Mackinawite) Nanostructures by Chemical Bath Deposition (CBD) Technique

Abstract: Fe1-xMnxS thin films with concentration x=0.02, 0.04, 0.06, 0.08, 0.1 have been deposited on glass substrates by a simple Chemical Bath Deposition (CBD) method at 90 oC. The X-ray Diffraction analysis of deposited thin films revealed the growth of mono-phasic mackinawite (FeS) structure with crystallite size in the range from 4.06 to 5.95 nm as a function of manganese concentrations. The other structural parameters like stacking faults, dislocation density and lattice strain affirmed the improvement in crystal structure and phase stability in manganese doped FeS thin films. Scanning Electron Micrographs depicted the growth of nano-flakes and nano-flowers in case of pure FeS thin films while for manganese doped iron sulfide thin films, homogeneity of the deposited material was observed to improve with distinct boundaries of almost spherical nanostructures. The direct energy band gap of FeS mono-phasic thin films was observed to decrease from 2.23 to 1.89 eV as the concentration of manganese increases in host lattice. The prepared thin films with tunable optical properties would have potential applications in energy conversion and optoelectronic devices.

Characterization of FeS2 Thin Film Prepared by Spray Pyrolysis Method for Optoelectronic Applications

In this work, the physical properties of iron sulfide (FeS2) thin films deposited by the chemical spray-pyrolysis (CSP) technique were studied. The thin films are deposited on glass substrates at 200oC, using FeCl3 salt with thiourea (NH2)2CS as precursors. Structural analysis of X-Ray diffraction manifested that the thin films contain two phases: Marcasite and Pyrite in planes (110), (111) at angles 2θ =26.3°, 2θ =28.3° respectively. Optical properties analysis showed that the prepared iron sulfide thin-films were highly absorbing in the UV-Visible range and the absorption coefficient was in the range of 1.6x105 cm-1 with a relatively low resistivity of about 0.49 (Ω.cm). The calculated activation energy (Ea) was 0.024 eV and the bandgap value was 2.45 eV. Moreover, the FeS2 thin films were also deposited on (CdO) to fabricate a heterojunction photocell. In conclusion, there is the feasibility of preparing low-cost and highly absorbing iron sulfide (FeS2) thin films for optoelectronic applications with acceptable homogeneity using the spray-pyrolysis technique.

Synthesis and characterization of copper zinc iron sulphide (CZFS) thin films

In an aqueous bath, quaternary thin films (TFs) of copper zinc iron sulphide (CZFS) were deposited on glass (soda-lime) substrates. The present study aimed to analyse the effect of deposition periods on the properties of the prepared CZFS TFs using Chemical bath deposition (CBD). The precursor and films were examined by Fourier Transform Infrared (FTIR) spectroscopy to check for the chemical formation present. Rutherford backscattering spectroscopy (RBS) was used to determine the elemental compositions and stoichiometry of the deposited films. The optical characteristics were observed by a UV-Vis Spectrophotometer and a four-point probe (FPP) for the electrical properties. The optical characterization revealed a direct transition band-gap energy that decreased from 1.96 to 1.50 eV with an increase in deposition period. The optical constants were studied with respect to the wavelength within the range of 300–900 nm. The films exhibited high resistive properties with a conductivity that varied with an increase in deposition period. The effect of deposition periods on the optical properties of refractive index, extinction coefficient, and real and imaginary parts of dielectric constants has been reported. All these parameters were found to increase with deposition period except for the film deposited for 18 h (C3). These results confirm that the aqueous deposited CZFS films can be tuned for various optoelectronic applications.

Analysis and characterization of manganese doped FeS thin films

Fe1-xMnxS thin films with concentration have been deposited on glass substrates by a simple Chemical Bath Deposition (CBD) method at 90 oC. The X-ray Diffraction analysis of deposited thin films revealed the growth of mono-phasic mackinawite (FeS) with crystallite size in the range from 4.06 to 5.95 nm as a function of manganese concentrations. The other structural parameters like stacking faults, dislocation density and lattice strain affirmed the improvement in structure and phase stability in manganese doped FeS thin films. Scanning Electron Micrographs depicted the growth of nano-flakes and nano- flowers in case of pure FeS thin films while for manganese doped iron sulfide thin films, homogeneity of the deposited material was observed to improve with distinct boundaries of almost spherical nanostructures. The direct energy band gap of FeS mono-phasic thin films was observed to decrease from 2.23 to 1.89 eV as function of doping concentration. The prepared thin films with tunable optical properties would have potential applications in energy conversion and optoelectronic devices.

Biological approach synthesis and characterization of iron sulfide (FeS) thin films from banana peel extract for contamination of environmental remediation

Biological approach synthesis and characterization of Iron Sulfide (FeS) thin films from banana peel extract for contamination remediation of environment studied. Iron chloride, Sodium thiosulfate and Ethylene-di-amine-tetra acetate (EDTA) were used as precursor solutions without further purification. The nanoparticle of banana peel was extracted and prepared with synthesized FeS thin films and analyzed by X ray-diffraction for structural examination, Scanning electron microscope (SEM) for surface morphological analysis, Ultra-violet-visible-spectrometer (UV–Vis) and photo-luminescence spectro-photo-meter (P-L) for optical characterizations. XRD peaks are shown with recognized to (110), (200), (310), and (301) crystalline planes. The occurrence of this deflection peak are recognised the FeS crystal segment of the tetragonal crystalline systems. SEM micrographs of the films prepared biological method show the distribution of grains, which cover the surface of the substrate completely and are uniform and films deposited purely have defects. The photo-luminescence, absorbance, and transmittance strength of banana peel extract FeS thin film is greater than pure FeS thin films in which wide-ranging and symmetries groups were perceived. In the present study, the comparison of pure FeS thin films and Nano synthesized banana peel extract with FeS thin films was studied. It is observed that Nano synthesized banana fibre absorbs higher than pure FeS thin films in solar cell application. Finally, green synthesis is an ecofriendly, easy and cheap promising method for the fabrication of thin films for solar cell applications.

Optimization of superhydrophobicity at the surface of iron sulfide thin films by a wet chemical approach

Superhydrophobic iron sulfide thin films were prepared by stearic acid (STA) chemically adsorbed onto the iron sulfide thin films deposited by aerosol assisted chemical vapour deposition (AACVD) using a single source precursor (tris(N,N-diethyldithiocarbamato)iron(III)). The microstructure of the iron sulfide thin films has been characterized by means of X-ray diffraction, scanning electron microscopy, water contact angle measurement, Fourier transformation infrared (FTIR) spectroscopy, white light interferometry (WLI) and X-ray photoelectron spectroscopy (XPS). The thin films exhibited superhydrophobicity and the static contact angle for water on the surface of iron sulfide thin films was as high as 157° in a fully optimised case. The ability to make the films superhydrophobic with a simple chemical treatment could be useful for a range of applications including prevention of water based corrosion pathways in oil and gas pipelines.

The Effect of Deposition Time and Sulfurization Temperature on The Optical and Structural Properties of Iron Sulfide Thin Films Deposited from Acidic Chemical Baths

Pyrite phase FeS2 thin films have been grown by a two-stage process of chemical bath deposition followed by sulfurization. Thiourea and thioacetamide were used as sulfur precursors in separate baths. The deposition time was controlled for 1, 2, and 3 hours respectively. The as-deposited films were sulfurized at temperatures of 250 oC and 500 oC to form the pyrite phase. The effect of deposition time and sulfurization temperature on the structure, morphology and optical properties of the iron pyrite films obtained from the two separate baths were studied and compared. X-ray diffraction analyses established the formation of the pyrite phase in all the films after sulfurization, in addition to iron (II) oxide hydrate as impurities. All films showed further improvement in pyrite formation, crystallinity as well as an increase in crystallite size after sulfurizing at 500 oC. EDAX and SEM microscopy showed that the iron pyrite films produced from the bath containing thiourea, had better crystallinity and a higher iron content. The optical band gap of the iron pyrite films obtained with thiourea, was 2.1, 1.9 and 1.6 eV for the various deposition times. With thioacetamide, the band gap was 1.4 eV, for the deposition time of 3 hours.

Plasma Diagnostics in Reactive High-Power Impulse Magnetron Sputtering System Working in Ar + H2S Gas Mixture

A reactive high-power impulse magnetron sputtering system (HiPIMS) working in Ar + H2S gas mixture was investigated as a source for the deposition of iron sulfide thin films. As a sputtering material, a pure Fe target was used. Plasma parameters in this system were investigated by a time-resolved Langmuir probe, radio-frequency (RF) ion flux probe, quartz crystal monitor modified for measurement of the ionized fraction of depositing particles, and by optical emission spectroscopy. A wide range of mass flow rates of reactive gas H2S was used for the investigation of the deposition process. It was found that the deposition rate of iron sulfide thin films is not influenced by the flow rate of H2S reactive gas fed into the magnetron discharge although the target is covered by iron sulfide compound. The ionized fraction of depositing particles decreases from r ≈ 40% to r ≈ 20% as the flow rate of H2S, QH2S, changes from 0 to 19 sccm at the gas pressure around p ≈ 1 Pa in the reactor chamber. The electron concentration ne measured by the Langmuir probe at the position of the substrate decreases over this change of QH2S from 1018 down to 1017 m−3

Synthesis of iron sulfide thin films and powders from new xanthate precursors

A series of novel alkylxanthato iron(III) precursors [Fe(S2COR)3] (R = n-butyl, (1); 2-butyl, (2); 2-methoxyethyl, (3); and 2-ethoxyethyl (4)) have been synthesised and their single crystal X-ray structures have been studied. The complexes were used as single-source precursors for the deposition of iron sulfide thin films as well as nanostructured powders using spin coating technique and solventless thermolysis respectively. Cubic pyrite was obtained using n-butyl xanthato iron(III) and 2-butyl xanthato iron(III) complexes in the temperature range of 200 to 300 °C. Structural and morphological investigations using XRD and SEM have been performed to ascertain the crystallinity and morphology of as-prepared thin films and nanostructures. The elemental composition was determined using energy dispersive X-ray (EDX) spectroscopy. The optical band gap energies of pyrite thin films produced by these methods were direct with estimated values in the range 1.6 to 2.3 eV.

Growth of well-ordered iron sulfide thin films.

In this paper a growth recipe for well-ordered iron sulfide films and the results of their characterisation are presented. The film was studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED), and scanning tunneling microscopy (STM). XRD data reveal that the film has a NiAs-like structure with Fe vacancies, similar to iron sulfides such as pyrrhotite and smythite, although no indication of any ordering of these vacancies was observed. LEED and STM results show that the film exhibits a 2 × 2 surface reconstruction. XPS data provide additional evidence for a large number of Fe vacancies, and the oxidation states of the Fe and S in the film are analysed.

Effect of complexing agents: investigations on structural, morphological, topographical and optical analysis of copper iron sulphide thin films deposited by chemical bath deposition method

Copper iron sulphide (FeCuS2) thin films deposited by chemical bath deposition method using ferrous sulphate and copper sulphate as cationic sources and sodium sulphide as anionic source with complexing agents, EDTA and Leishman stain were reported. The structural, optical and morphological studies were carried out using X-ray diffraction, scanning electron microscopy (SEM), atomic force microscopy (AFM) and UV–Visible spectroscopy techniques. The X-ray spectrum reveals that the films are polycrystalline nature and also showed the deposition of cubic phases at room temperature. The SEM images for prepared films have clear morphology influenced by the complexing agents used in deposition process. The result of AFM studies shown that the particles in the film have grain size around ~ 60–70 nm and also have almost similar thickness. Based on the optical absorbance spectra the FeCuS2 film exhibited a high absorbance in the visible region. The absorption edge shifted toward lower wavelength with varying complexing agents. The band gap value obtained was found to be 3.57–3.85 eV. From these results, it is indicated that the prepared films are suitable candidate for solar cell applications.

Synthesis of nanostructured powders and thin films of iron sulfide from molecular precursors.

Iron(iii) xanthate single-source precursors [Fe(S2COR)3] (R = methyl, ethyl, isopropyl and 1-propyl) were used to deposit iron sulfide thin films and nanostructures by two simple, efficient and low-cost methods (spin coating and solid state deposition). The single-crystal X-ray structures of the iron(iii) n-propyl xanthate and iron(iii) iso-propyl xanthate have been determined. Thermogravimetric analysis (TGA) studies of the complexes shows that decomposition of the complexes produces iron sulfide, pyrite or trolite. The crystallinity of iron sulfide thin films and powder samples was studied using X-ray diffraction (XRD), and their morphology was studied by scanning electron microscopy (SEM).

Synthesis of Iron Sulfide and Iron Oxide Nanocrystal Thin Films for Green Energy Applications

Solar radiation and hydrogen generation via splitting water molecules have been recognized as sustainable and clean energy sources having great industrial potentials. In this regard, thin film materials for photovoltaic and photoanodes applications have been widely developed in the last decade. For thin film photovoltaic applications, taking material availability, extraction/processing cost, energy conversion efficiency, and eco-friendliness into account, FeS2 (pyrite) has been predicted to hold the leading position among the most plausible candidates such as Cu2S, Cu2O, CuO, etc. On the other hand, feasible water splitting on nanostructured surface and/or hybrid nanostructures has been observed in the last few years. In terms of processing cost, feasibility in scale-up for mass production, material engineering for efficiency, etc., physical vapor depositions (PVDs), e.g., magnetron-sputtering deposition, have great advantages. Here, we present our recent studies on synthesis of iron sulfide and oxide layered and nanostructured films by combining PVD and thermal vapor sulfurization/oxidation techniques.

Heterocyclic dithiocarbamato-iron(III) complexes: single-source precursors for aerosol-assisted chemical vapour deposition (AACVD) of iron sulfide thin films.

Tris-(piperidinedithiocarbamato)iron(III) (1) and tris-(tetrahydroquinolinedithiocarbamato)iron(iii) (2) complexes have been synthesized and their single-crystal X-ray structures were determined. Thermogravimetric analysis (TGA) of the complexes showed decomposition to iron sulfide. Both complexes were then used as single-source precursors for the deposition of iron sulfide thin films by aerosol-assisted chemical vapour deposition (AACVD). Energy-dispersive X-ray (EDX) spectroscopy confirmed the formation of iron sulfide films. The addition of tert-butyl thiol almost doubled the sulfur content in the deposited films. Scanning electron microscopy (SEM) images of the iron sulfide films from both complexes showed flakes/leaves/sheets, spherical granules and nanofibres. The sizes and shapes of these crystallites depended on the nature of the precursor, temperature, solvent and the amount of tert-butyl thiol used. The observed optical properties are dependent upon the variation of reaction parameters such as temperature and solvent. Powder X-ray diffraction (p-XRD) studies revealed that pyrrhotite, hexagonal (Fe0.975S), marcasite and smythite (Fe3S4) phases were differently deposited.

Synthesis of mackinawite FeS thin films from acidic chemical baths

The growth of monophasic iron sulfide thin films onto glass substrates has been achieved by chemical bath deposition at acidic values of pH. Powder X-ray diffraction (p-XRD) confirms the deposition of tetragonal FeS (mackinawite) with preferred orientation along (001) plane. The crystallite size estimated by Scherrer equation was found to be 14nm. Scanning electron microscopy (SEM) shows the formation of nanoflakes as base layer and nanoflowers as top layer. Energy Dispersive X-ray (EDX) analysis of the deposited iron sulfide thin films shows the iron to sulfur ratio close to 1:1 confirming the deposition of FeS. UV–vis absorption spectroscopy showed a blueshift due to the nanosize crystallites FeS with a band gap of 1.87eV.

Growth of semiconducting iron sulfide thin films by chemical vapor deposition from air-stable single-source metal organic precursor for photovoltaic application

Semiconducting nanostructured iron sulfide thin films were prepared by aerosol chemical vapor deposition at 673 and 723 K from newly synthesized iron complex of dithiocarbo-1,2,3,4-tetrahydroquinoline [Fe(S2CNC9H10)2]. The degree of film surface roughness was determined by atomic force microscopy. The nature of the deposited thin films formed was determined by a combination of EDX analysis and glancing angle X-ray diffraction.

Electrochemical deposition of iron sulfide thin films and heterojunction diodes with zinc oxide

Iron sulfide thin films were fabricated by the electrochemical deposition method from an aqueous solution containing FeSO4 and Na2S2O3. The composition ratio obtained was Fe:S:O = 36:56:8. In the photoelectrochemical measurement, a weak negative photo-current was observed for the iron sulfide films, which indicates that its conduction type is p-type. No peaks were observed in X-ray diffraction pattern, and thus the deposited films were considered to be amorphous. For a heterojunction with ZnO, rectification properties were confirmed in the current-voltage characteristics. Moreover, the current was clearly enhanced under AM1.5 illumination.

Effects of strontium and aluminum impurities on optical properties of iron sulfide (FeS2) thin films

Chemical bath deposited iron sulfide (FeS2) thin films were grown at room temperature (26 o C) on glass substrates and the effects of impurity concentrations of strontium (Sr, 0.02-0.04M) and aluminum (Al, 0.02-0.04M) on the optical properties of the FeS2 thin films were investigated using a spectrophotometer in the UV-VIS region. The highest transmittance of 70% occurred for 0.04M Al impurities and 27% for 0.02M of Sr impurities as compared to 18% for un-doped iron sulfide thin films, while the reflectance exhibited varying peak values at 550 nm and 650 nm wavelengths for all concentrations of both impurities. Other optical properties obtained from the spectrophotometer data using appropriate relations showed a corresponding low absorbance of 0.2 for 0.04M Al impurity and fairly high absorbance of 0.6 for 0.02M of Sr impurity. A significant increase in the energy band gap occurred from 1.9 - 2.2eV for Strontium impurity concentrations and 2.0 - 3.8eV for Al impurity concentrations with the highest of 3.8eV at 0.04 Al doping. The effects of Sr and Al dopants on the extinction coefficient and refractive index of the thin films are also reported in this paper.

Analysis of Structural and Electrical Properties of Iron Sulfide (FeS2)Thin Films doped with Aluminum and Strontium impurities

Abstract: Thin films of iron sulfide (FeS2) prepared by CBD technique were doped with aluminum (Al: 0.020.04M) and strontium (Sr: 0.02-0.04M) impurities at room temperature of 26 C. X-Ray diffraction (XRD) and four-point probe were used to analyze the structural and electrical properties of the thin films. The XRD results show that 0.02M of strontium impurities produced polycrystalline structure of the thin films with diffraction peak values located at Bragg’s angles, 2Θ of 14.71, 25.03 and 34.95, while the un-doped polycrystalline FeS2 thin films have diffraction peaks at 2Θ values of 19.81, 24.43, 31.45 and 36.73. Clearly, the contributing inphase reflections for the different diffraction angles occur from different orientations of lattice planes and/or different crystallite sizes caused by the Sr impurity. On the other hand, 0.02M of aluminum dopant produced mono-crystalline structure of the FeS2 thin film with 2Θ value of 24.97 o and a broadened full width at half maximum (FWHM). It is remarkable that the single peak of the mono-crystal due to Al impurity coincides with the highest intensity and sharper peak of the un-doped FeS2 thin film. The electrical resistivity of the thin films decreased while the conductivity increased with increase in impurity concentrations with non-uniform changes occurring from 0.02M for both impurities. The film thickness remained between 0.09-0.1μm but showed a more dramatic increase with impurity concentration from 0.02M for both impurities.

Ageing mechanisms of conversion-type electrode material studied on iron sulfide thin films

The morphological and chemical modifications induced by repeated cycling of conversion-type negative electrode material were studied for iron sulfide thin films in 1M-LiClO4/PC by combining AFM, XPS and ToF-SIMS analysis with electrochemical control. The topographical changes were consistent with irreversible swelling of the material caused by repeated volume expansion/contraction. A 3% capacity fading measured after 9 conversion/deconversion cycles resulted mainly from the loss of electroactive material forming pinhole defects in the thin film electrode. Repeated cycling caused increasing accumulation of non deconverted material in the bulk thin film electrode. Repeated cycling also resulted in continuous surface up-take and increasing accumulation of the SEI layer in the bulk thin film electrode, rich in Li2CO3. Formation of a duplex-like structure with organic and inorganic compounds primarily distributed in the outer and inner parts, respectively, was suggested by ToF-SIMS depth profiling of the SEI layer.