Properties Of SnS Thin Films Research Articles

Tailoring the opto-electronic properties of SnS thin films by indium doping and fabrication of heterojunction diodes

This study comprehensively investigates the effect of Indium (In) doping on the structural, morphological, and optoelectronic properties of tin mono-sulfide (SnS) thin films deposited using co-evaporation. X-ray diffraction studies identified the orthorhombic phase of SnS. Raman analysis confirmed the formation of SnS by co-evaporation. Morphological analysis revealed uniform coating of the films, a transition from rod-like to regular grain-like structures with increased In doping. A systematic reduction in Sn concentration, with the increase in In is observed in EDS, indicating the substitutional doping of In. The decrease in root mean square roughness with In incorporation suggests smoother film surfaces. The films demonstrated a pronounced improvement in optoelectronic properties, with a notable increase in the absorption coefficient and a bandgap reduction from 2.18 eV to 1.74 eV, resulting from In doping. A significant enhancement in electrical characteristics is observed, including a 140 % increase in conductivity and a systematic rise in carrier concentration with higher In doping levels. Heterojunction devices are fabricated with structure <FTO/Al:ZnO/In:SnS/Ag> having a series resistance of 29.9 Ω having an ideality factor of 2.8.

Tailoring the properties of SnS thin films deposited at room temperature by varying the amount of complexing agent for enhanced photocatalytic activity

This work examines how the characteristics and photocatalytic efficacy of modified SILAR-deposited SnS thin films are affected by the addition of a complexing agent. Stannous chloride dihydrate and sodium sulphate were used as tin and sulphur sources, respectively, while triethanolamine (TEA) served as a complexing agent in film deposition. The modified SILAR method facilitated the formation of well-adhesive thin films on the glass substrate at room temperature. The formation of SnS was demonstrated using EDAX and XPS analysis. XRD analysis proved that all the films are polycrystalline in nature with an orthorhombic crystal structure. The presence of chlorine as an involuntary dopant was observed in all the films prepared with TEA. Optical studies employing UV–visible spectroscopy found that all of the films have good visible absorption, with bandgap values ranging from 1.58 eV to 2.2 eV. Even though the films were deposited at room temperature, all films exhibited good thermal stability as per TGA analysis. The introduction of TEA caused improvements in the adhesion of the film to the substrate, a decrease in the band gap, a change in the morphology and composition, and an increase in the crystallinity and crystallite size. Due to their suitable bandgap corresponding to the visible region, SnS thin films exhibited good photocatalytic efficiency in degrading various types of dyes. The SnS thin film catalyst reduced 97% of methylene blue in 90 min at room temperature without using any reducing agent. The LCMS analysis validated the photocatalytic degradation of dye, whereas the UV–visible spectroscopic analysis gave a quantitative measure of the degradation efficiency. The reduction in photodegradation efficiency in the presence of OH radical scavengers confirmed the role of OH radicals in the degradation process. The terephthalic acid test further demonstrated the generation of OH radicals during the dye degradation process. The observed increase in photocatalytic activity of SnS thin films with TEA addition could be due to TEA-induced bandgap reduction, crystallinity increase, and crystallite size increase. The catalyst was reusable, stable, easy to recover after use, and effective against various kinds of dyes. The study emphasizes the use of complexing agents as a useful tool for modifying the characteristics and, consequently, the photocatalytic efficiency of modified SILAR-deposited SnS thin films.

Influence of deposition pressure of elemental Sn on structural, optical, electrical and schottky diode properties of SnS thin films grown by two-stage method

Influence of deposition pressure of elemental Sn on structural, optical, electrical and schottky diode properties of SnS thin films grown by two-stage method

Fabrication of p-type and n-type SnS thin films through vacuum-free deposition techniques

Here, SnS thin films having p and n-type conductivity were fabricated using vacuum-free deposition techniques such as chemical bath deposition (CBD) and chemical spray pyrolysis technique (CSB). The fabricated thin films were subjected to structural, morphological, optical, and electrical analysis using various characterization techniques. The direct optical bandgaps of the SnS-based thin films are 1.80 eV and 1.66 eV. The absorption coefficient of SnS thin films fabricated by the CSP technique is 105 cm−1. The electrical properties of SnS thin films were analyzed by a hall measurement system. The type of conductivity obtained for the SnS thin films was different for both deposition techniques. In the CBD method, p-type conductivity were obtained for SnS films. The SnS thin films fabricated by the CSP technique possess n-type conductivity. The optimum bandgap, high absorption coefficient, type conversion nature and suitable morphology helps the material as potential candidate for thin film based energy generation and energy conversion applications.

Fabrication of SnS thin film by rapid thermal processing: effect of annealing temperature in sulfurization process

In this study, the effect of sulfurization temperature on properties of SnS thin films was investigated. The SnS thin films were fabricated by two-stage method includes deposition of SnS films by magnetron sputtering using a single SnS target, followed by annealing/sulfurization treatment in Rapid Thermal Processing (RTP) system at 225, 300 and 375 °C temperatures. Several characterization techniques such as XRD, Raman spectroscopy, EDX, optical transmission and Van der Pauw were used for analyses of the films. The EDX analyses showed that all the samples had almost stoichiometric (S/Sn~1) chemical composition. However, the amount of sulfur in the samples increased slightly as the sulfurization temperature increased. XRD pattern of the films exhibited constitution of orthorhombic SnS structure regardless of annealing temperature. The SnS2 secondary phase was observed in addition to orthorhombic SnS phase in the sample annealed at highest reaction temperature (375°C). Raman spectroscopy measurements of the films verified constitution of orthorhombic SnS structure. The band gap of the films exhibited distinction from 1.42 to 1.81 eV regarding to annealing temperature. The electrical characterization of the most promising SnS thin film sulfurized at 300°C had resistivity and charge carrier concentration values 1.07x104 Ω.cm and 1.70x1014 cm-3, respectively. Based on the all characterizations, it can be deduced that SnS thin film sulfurized at 300°C exhibited more outstanding structural and optical properties for potential solar cell applications.

Structural and optical properties of tin sulfide nanostructures

This paper presents modification of tin sulfide (SnS) thin films by pulsed laser irradiation. Tin sulfide films of 1 µm thickness were prepared using chemical bath deposition (CBD) technique. The chemical bath contained 5 ml acetone, 12 ml of triethanolamine, 8 ml of 1 M thioacetamide, 10 ml of 4 M ammonium hydroxide and 65 ml of distilled water. The chemical bath was kept at a constant temperature of 60 °C for 6 h which resulted in SnS films with 500 nm thickness. By double deposition, the final thick- ness of SnS thin films obtained was 1 µm. Laser processing was conducted to modify the structure, morphology and physical properties of the SnS thin films. The laser specifications were pulsed Nd:YAG laser with 532 nm wavelength, 300 mJ pulse energy and 10 ns pulse width. Properties of the laser-irradiated SnS thin films were compared with the as- prepared SnS thin films. The changes in structure, morphology, optical and electrical properties of the laser-irradiated SnS thin films were described.

Experimental and numerical simulation of the performance of SnS based solar cells

In the present study, the SnS thin films have been grown using the sol gel spin coating technical deposed on a glass substrate. The structural analysis of SnS thin films was examined using X-ray diffraction (DRX). The optical properties of SnS thin films have been investigated using the spectrophotometer UV-V, and we calculated the sum of the optical parameters such as the absorption coefficient, refractive index, the extinction coefficient, the real and imaginary part of the dielectric constant, and the optical conductivity. The electrical resistivity has been calculated using the four-point probe method. The performance of the SnS based proposed solar cells studied from the numerical simulation using SCAPS-1D software. The SnS-thickness, CdS-thickness, and ZnO-thickness are optimized. The SnS-band gap optimization showed that the optimal value is 1.55 eV this is similar to the value found experimentally (∼1.58 eV). The influence of the operating temperature, series and shut resistor, and SnS/CdS charge interface defect on the parameters on the performance solar cells are investigated.

Thickness-dependent Raman active modes of SnS thin films

Tin sulfide (SnS) thin films have been reported to show strong layer number dependence on their ferroelectricity and Raman spectra. Identifying the number of layers and stacking structures is crucial for optoelectronic device fabrication. Here, we theoretically study the electronic and phononic properties of SnS thin films using first-principles calculations. We identify the characteristic Raman active phonon modes and their dependence on the number of layers and stacking sequences. The clear separation between surface modes and bulk modes is clarified for SnS thin films. In addition, we have clarified the relation between stacking structures and Raman active modes for bilayer SnS. Our results will serve the experimental characterization of such thin monochalcogenide systems through Raman spectra and will expedite their device fabrication.

Annealing temperature effect to optimize the optical properties of SnS thin films

Annealing temperature effect to optimize the optical properties of SnS thin films

Impact of in/ex situ annealing and reaction temperature on structural, optical and electrical properties of SnS thin films

In this work, SnS thin films were prepared by in situ and ex situ annealing process of precursor films deposited by RF (Radio Frequency) magnetron sputtering employing binary SnS target. In situ annealing treatment was performed in sputtering chamber and ex situ annealing treatment was performed using RTP (Rapid Thermal Processing) system under Ar+H2 mix gas employing 225, 300 and 375 °C as reaction temperatures in order to find out the best fabrication parameters of SnS thin film since it has been used as an absorber layer in the cell structure. The EDX (Energy Dispersive X-ray Spectroscopy) measurements showed that precursor and reacted films have almost stoichiometric composition except for in situ annealed sample at 375 °C. XRD (X-ray Diffraction) patterns of all samples revealed orthorhombic SnS phase regardless of annealing route and temperature. In addition to SnS phase, formation of SnS2 phase was observed in in situ annealed SnS samples at 225 and 300 °C. Moreover, in situ annealed samples displayed larger crystallite size and lower micro strain compared to ex situ annealed samples. Raman spectra of the samples confirmed formation of orthorhombic SnS phase and it was also seen that crystalline quality gave rise to shift in position of Raman bands for some samples. Only a SEM (Scanning Electron Microscopy) image of in situ annealed sample at 375 °C displayed distinct surface morphology. Optical band gap values of the samples showed variation between 1.35 and 1.66 eV. Electrical characterization of the films showed that resistivity values changed from 3.34×103 to 2.28×104 Ω-cm and carrier concentration values changed from 1.34×1014 to 1.05×1015 cm−3. It was seen that in situ annealing at 375 °C exhibited more promising results for potential SnS based photovoltaic applications.

From thin films to shaped platelets: effects of temperature gradient on SnS synthesis

In this work, we studied the synthesis and properties of SnS thin films and platelets obtained by vapor phase deposition under controlled pressure. Two morphological types are obtained in the same process depending on the absolute temperature and the temperature gradient inside the reactor. The growth of isolated platelets is favored by a small temperature gradient between the sublimation and deposition regions of the deposition chamber. Films are formed when there is a large temperature gradient. Raman spectroscopy and energy dispersive spectroscopy analysis were used to identify the phase of the synthesized samples, and polarized Raman spectroscopy and X-ray diffraction analysis helped us confirm the crystallographic orientation of the isolated platelets. We have carried out studies on the crystallographic shape and orientation of orthorhombic isolated platelets using optical microscopy, scanning electron microscopy and surface energies of the crystalline planes of SnS.

Optical, electrical and electronic properties of SnS thin films deposited by sol gel spin coating technique for photovoltaic applications

In the current study, thin films of tin sulfide (SnS) were grown by sol–gel spin-coating technique deposited on glass substrates. The obtained thin films were characterized using X-ray diffraction (XRD), photoluminescence (PL) and UV–Vis spectrometer and the four point technique, respectively. The effect of annealing temperature on the SnS properties has been studied. The XRD results reveal that the films annealed at 500 °C have good crystalline quality with orthorhombic phase. Fourier-transform infrared spectroscopy (FTIR) spectra shows the Sn–S bond. The photoluminescence spectra showed two categories of band emission. The optical parameters (α, e, n, k, Eg, and σop) were determined using UV–Vis spectroscopy. Moreover, the obtained results were compared to the theatricals results obtained with density functional theory (DFT) method using ab-initio approach. The optical and the electrical properties of the SnS Layers annealed at 400 °C and 500 °C offer the best possibility for their utilization in photovoltaic applications.

Investigation on the performance of SnS solar cells grown by sputtering and effusion cell evaporation

SnS is an earth-abundant, non-toxic, and low-cost absorber material for solar cell applications. In this work, the physical properties of SnS thin films and efficiency of SnS solar cells were investigated for different tin metal layer thicknesses of 300 nm (Sn-300), 500 nm (Sn-500), and 700 nm (Sn-700) deposited by DC sputtering followed by the sulfurization using effusion cell evaporation method. The XRD and Raman characterizations confirmed the formation of single-phase SnS compound with orthorhombic structure for the case of Sn-500. The sulfurized films of Sn-500 had remarkable and homogeneous morphology with the optical band gap energy of 1.35 eV. The fabricated device showed an efficiency of 0.74% with an open-circuit voltage of 267mV, short circuit current density of 8.47 mA/cm2, and fill factor of 54.16. By varying the different metal tin layer thicknesses, this is the first report with device efficiency for SnS solar cells grown via effusion cell evaporation technique.

Effect of pH on the optical and structural properties of SnS prepared by chemical bath deposition method

In this work we study the influence of pH on the optical and structural properties of SnS thin films. The films were grown on the glass substrate using chemical bath deposition method. Hydrous tin chloride and thioacetamide were used as cationic and anionic precursors respectively. The pH of the solution was changed using Ammonia. The film was prepared at five different pH values 9.2, 9.3, 9.4, 9.5 and 9.6. The optical and structural properties were studied using UV Visible spectrophotometer and XRD. From optical characterisation it was found that the band gap decreases as the pH increases from 9.2 to 9.5. The crystallanity of the film increased as the pH value increased.

Effect of sulfurization temperature on the efficiency of SnS solar cells fabricated by sulfurization of sputtered tin precursor layers using effusion cell evaporation

Earth-abundant tin monosulfide (SnS) thin films have attracted considerable interest for eco-friendly and low-cost thin film solar cells. However, less attention has been paid on the fabrication of SnS solar cell by the industrial processes. In view of that the current study aimed to fabricate the SnS solar cells via two-stage (sputtering + sulfurization) industrial process. For the preparation of SnS thin films, first tin metallic precursor layers were deposited by DC sputtering and then sulfurized using the rapid thermal effusion cell evaporation process. The effect of sulfurization temperature on the physical properties of SnS thin films and the efficiency of SnS solar cells was examined. Formation of the single phase SnS thin films was confirmed when the tin metallic precursor layers sulfurized in the range of 450–470 °C, whereas secondary phases of Sn, SnS2, and Sn2S3 were noticed at the sulfurization temperature lower than 450 °C and re-evaporation of deposited SnS thin films was observed at the sulfurization temperature higher than 470 °C. Solar cell fabricated with SnS absorber sulfurized at a temperature of 470 °C showed the conversion efficiency of ∼ 2.3%. The causes for lower efficiency of these solar cells were recombination in the SnS absorber and non-uniform compositional distribution of Cd, S and Sn as a function of depth in the CdS/SnS/Mo structure.

Chemical Spray Pyrolysis pure and Transition Metal doped Structural, Morphological and Optical properties of SnS Thin Films

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Tuning optoelectronic properties of SnS thin films by a kinetically controllable low temperature microwave hydrothermal method

In the polycrystalline SnS semiconductor films, the crystallite size and stoichiometry play a central role in dictating their optoelectronic properties. Most strategies to tailoring these parameters require long-time deposition methods and post-deposition thermal annealing at high temperature under inert atmosphere or sulfur vapor. Here, we report a different strategy of tuning optoelectronic properties of SnS films by controlling the kinetical parameters in a microwave-hydrothermal solution method at low temperatures (50–60 °C). The interaction between microwave radiation and the highly polar thioacetamide (TA, sulfur source) enhances local temperature in the reaction solution and permits a rapid formation of orthorhombic SnS crystallites on glass substrates. For as-deposited SnS films, a lineal dependence is observed of the film thickness, crystallite size and electrical conductivity on the TA concentration. In addition, the microstrain, Sn/S ratio and optical band gap of the films decrease with the concentration of TA, leading to the optimal values for stoichiometry and optical properties of SnS films. The ability to synthesize highly crystalline SnS thin films at high growth rates and low temperatures opens up possibilities to the fabrication of SnS-based optoelectronic devices on plastic substrates.

Effect of carrier gas pressure on structural, optical and photovoltaic properties of tin sulphide thin films prepared by nebulizer spray pyrolysis method

Tin sulphide (SnS) thin films deposited using nebulizer spray pyrolysis technique by changing pressure (0.1, 0.15, 0.2 and 0.25 Pascal) at $$350^{\circ }\hbox {C}$$ and their characterization are reported. The influence of carrier gas pressure on structural, morphological, optical and electrical properties of the film are determined using X-ray diffraction (XRD), energy-dispersive X-ray, atomic force microscopy, UV–Vis spectrophotometry and Hall effect measurement. Structural parameters such as pole density, orientation factor, crystallite size, micro strain and dislocation density were analysed using XRD data. The scanning electron microscopy studies display superior morphology and surface roughness of the films which were found to increase with pressure. Optical studies on the films revealed a variation in band gap from 1.78 to 1.66 eV for were the raise of pressure from 0.1 to 0.2 Pa. A single strong emission peak at about 825 nm is observed in photoluminescence spectra with enhanced intensity which may be attributed to near band edge emission. Grown SnS thin film exhibits p-type conductivity, which was confirmed from the Hall effect measurement. The low resistivity and higher carrier concentration are found to be $$0.235\,\Omega \,\hbox {cm}$$ and $$5.04\times 10^{18}\,\hbox {cm}^{-3}$$ , respectively. These properties were then correlated with the deposition parameters. Furthermore, to study the photovoltaic properties of SnS thin films, a heterojunction solar cell FTO/n-CdS/p-SnS/Al was fabricated showing conversion efficiency of 0.16%.

Dependence of pH on phase stability, optical and photoelectrical properties of SnS thin films

This study reports the effect of pH value of the reaction solution (5, 5.8 and 6.5) on growth rate of SnS films deposited by chemical bath deposition and their characteristics such as X-ray diffraction (XRD), surface morphology, phase stability, optical and photoelectrical. XRD analysis reveals that the films exhibit an orthorhombic structure with polycrystalline nature, in addition to the presence of the secondary phase Sn2S3 at pH 6.5. Field emission scanning electron microscopy observations show the formation of nanoflowers. Raman spectra manifest the presence of Sn2S3 phase, where its peak intensity gradually reduces until disappearance with decreasing pH value from 6.5 to 5. Furthermore, the enhancement in the dark current (conductivity) value of the thin films occurs with decreasing pH value, as well as increasing in the value of photocurrent under illumination of near-infrared 750 nm. Conversely, the sensitivity value decreased with decreasing pH. Moreover, the energy gap value ranges from 1.34 to 1.51 eV with increasing pH. The as-obtained results demonstrate the key role of pH in controlling SnS films characteristics to achieve high quality films for the applications of photodetectors and solar cells.

Effect of C4H6O6 concentration on the properties of SnS thin films for solar cell applications

SnS thin films were prepared by chemical bath deposition using an environmentally friendly and economic complexing agent, tartaric acid (C4H6O6) with different concentrations. X-ray diffraction analysis confirmed that all the deposited films exhibited polycrystalline nature with a predominant plane of (1 1 1) related to an orthorhombic structure. The intensity of the (1 1 1) plane increased with increasing concentration of the complexing agent. Raman spectra of the films showed the characteristic vibrational modes at 94, 160, 191, and 217 cm−1, corresponding to orthorhombic SnS. SEM micrographs showed homogeneous surfaces with the presence of nut-shaped grains. The optical absorption coefficient for the prepared films was >104 cm−1, representing that the deposited films showed high absorption. Electrical studies revealed the p-type conducting nature of the deposited films. The SnS solar cell fabricated with a tartaric acid concentration of 1.2 M showed the highest efficiency of 1.62% with an open-circuit voltage of 0.283 V, a short-circuit current density of 13.9 mA cm−2, and a fill factor of 41.1%.