Zinc Sulfide Thin Films Research Articles

Absence of Mn emission in MnxZn(1-x)S thin films grown by spray pyrolysis technique

In the present investigation, the effect of manganese (Mn) dopant on zinc sulfide (ZnS) thin films used for blue light emitting diode was studied. The basic studies on the structural and morphological properties showed good crystallinity up to 2 at % Mn concentration. Samples were studied for the presence of defects using models of Urbach energy and near-edge absorptivity ratio (NEAR). Upon manganese doping, enhancement in the blue emission (in the wavelength region ~ 400 nm) was observed, and interestingly, the Mn related orange emission was not observed. Here, we explained the possible reasons for the suppression of this signature orange emission. Present work is compared with various other reports on manganese doped zinc sulfide (MnxZn(1-x)S). The properties of the MnZnS films were characterized using spectroscopic techniques like static and time resolved photoluminescence (TRPL) along with X-Ray photoelectron spectroscopy (XPS). Measured lifetime of defects was in several hundreds of pico-second. From the spectroscopic characterizations, anomalous behavior of Mn related defects in the MnZnS thin films were explained. An extensive study on XPS of the prepared MnxZn(1-x)S thin film gave greater insight to the possible mechanism for this anomalous luminescence behavior.

Electrodeposition of copper (II) sulfide and zinc sulfide onto polycrystalline gold electrode

An electrodeposition-based process was developed in this work. Electrochemical atomic layer epitaxy (ECALE) and co-deposition methodologies were employed to grow copper (II) sulfide (CuS) and zinc sulfide (ZnS) thin films as photovoltaic semiconductors on polycrystalline gold electrode. The deposition potentials of copper (Cu), zinc (Zn) and sulfur (S) were defined separately by cyclic voltammetry. Thin films were created from an electrolyte containing copper (II) sulfate (CuSO4), sodium sulfur (Na2S) and zinc sulfate (ZnSO4) in ethylenediaminetetraacetic acid (EDTA) using both cyclic voltammetry and bulk electrolysis techniques. The influence of bath temperature at the deposition potential was studied to determine the crystallinity of deposits. From the chronoamperometry results including the transients obtained within the under potential region, the nucleation and growth process of deposits were estimated. In this way, an electrodeposition-based method for CuS and ZnS semiconductors in a comparable basis was improved on polycrystalline gold substrate.

Effect of annealing temperature and Mn doping on the structural and optical properties of ZnS thin films for enhanced photocatalytic degradation under visible light irradiation

Herein we report a facile and low cost Sol-Gel method was adapted to design and fabricate highly efficient ZnS photocatalyst. The zinc sulfide (ZnS) thin films have been prepared at different annealing temperatures (200, 300 and 400 °C) and annealing temperatures 400 °C was optimized for Manganese (Mn) doped ZnS (Zn1-x Mnx S) (10 wt%) thin films. The effect of annealing temperature and Mn doping on the structural, optical and photocatalytic properties of ZnS thin films were investigated in detail by using XRD, FESEM, EDS, UV–Vis., PL, XPS and N2 adsorption-desorption analysis. XRD pattern exhibited hexagonal crystal structure for prepared samples and average particle size was increased from 25 to 47 nm with increasing annealing temperature and Mn doping. FESEM images revealed that nanoflake like morphology for annealed samples further it’s found to disappear for Mn doped ZnS samples. The presence Mn2+ ions into ZnS lattice was found from EDS and XPS analysis. Optical properties was analyzed by using UV–Vis. and PL studies and it’s found photogenerated recombination process and surface related defects with considerable red shift within the absorption edge and significant narrowing the band gap energy of undoped ZnS by increased annealing temperature with Mn doping. The large surface area with mesopores nature and tuning the optical property in the visible light region could be improve the rapid photo degradation efficiency of methylene blue dye (MB) under stimulated visible light enlightenment. The ZnS:Mn thin films annealed at 400 °C catalyst showed excellent photodegradation efficiency (99%), good stability with better first order kinetic and easy reusability towards MB dye, furthermore the effect of annealing temperature and Mn doping for the enhanced photo catalytic mechanisms by visible light was also discussed.

Enhancing crystalline/optical quality, and photoluminescence properties of the Na and Sn substituted ZnS thin films for optoelectronic and solar cell applications; a comparative study

Zinc sulphide (ZnS) is one of the most important semiconductor for the optoelectronic devices. It is generally used as a buffer layer in highly efficient Cu(In,Ga)Se2 solar cells due to its environmentally friendly characteristics. Here, we studied the effects of Na+/Sn2+ substituent using a solution based method for improving characteristics and functions of Zn1-xNaxS/Zn1-xSnxS (x = 0–15%) thin films for such applications. The formation of Zn2+-S2-, Zn2+-Sn2+-S2-, and Zn2+-Na+-S2- bonding as well as the existence of Zn2+/Zn, Sn2+/Sn, S2−/S, Na+/Na, ions/elements have been examined by the FT-IR and XPS/EDX analysis. The produced films have mixed cubic and hexagonal polycrystalline structure with highly preferred orientation along (111) plane of predominant cubic phase. Comparatively, XRD, SEM, and AFM analysis clearly showed that the crystalline quality of the Zn1-xSnxS thin films is higher than those of Zn1-xNaxS thin films. The surface morphology of both type films is dense and homogeneous. The surface roughness of Zn1-xSnxS films has higher value as compared to the Zn1-xNaxS thin films. The optical quality of Zn1-xSnxS films was better than those Zn1-xNaxS films confirmed by UV–Vis analysis. Amongst of all the synthesized materials, 1% Sn substituted ZnS film sample has the best film crystallization and optical quality. The observed results suggested that it has a promising potential for the optoelectronic and solar cell applications.

Investigation on the structural, optical and photocatalytic degradation properties of Zns/Mn:Zns thin films under visible light irradiation

Undoped and Manganese (Mn) doped Zinc Sulfide (ZnS) thin films have been prepared by using a simple sol–gel dip coating method and as-prepared ZnS thin films annealed at 400 °C at hot air furnace in order to improve crystallinity. The influence of Mn doping and annealing temperature on the structural, morphological, optical and photocatalytic behavior of the ZnS thin films under visible light irradiation has been scientifically investigated by using XRD, FESEM, UV–Visible and Photocatalytic analysis. XRD results suggest that prepared ZnS thin films formed hexagonal phase and crystallite size was calculated as 25 and 40 nm for ZnS and Mn:ZnS respectively. FESEM analysis shows that the nonoflake like morphology observed for undoped ZnS thin films annealed at 400 °C and this nonoflake like morphology further disappeared for Mn:ZnS thin films. An optical analysis confirm that the absorption edge shifts toward longer wavelength (red shift), which confirm that decreasing the band gap energy was observed for Mn:ZnS thin films. Besides, photocatalytic activity of methylene blue (MB) dye was investigated by using ZnS and Mn:ZnS thin films as catalyst under visible light irradiation. The result suggest that Mn:ZnS thin films exhibited excellent photocatalytic degradation efficiency (94%) and high stability towards MB dye than compared to pure ZnS thin films.

Chemical bath deposition of aluminum doped zinc sulfide thin films using non-toxic complexing agent: Effect of aluminum doping on optical and electrical properties

Zinc sulfide (ZnS) and aluminum doped zinc sulfide (ZnS:Al) thin films have been prepared by chemical bath deposition onto glass substrates at 85 °C using non-toxic complexing agents by varying the Al concentration between 0 wt. % and 18 wt. %. The ZnS and ZnS:Al thin films exhibited a hexagonal wurtzite crystal structure and showed (008) preferential orientation. The Field Emission Scanning Electron Microscope (FESEM) images of the film showed that the glass substrate was nicely covered by compact and dense mosaic like nanostructures. The elemental composition of ZnS and ZnS:Al thin films was measured by energy dispersive x-ray spectroscopy. X-ray photoelectron spectroscopy (XPS) demonstrates the doping of Al into ZnS. From the XPS spectra, the binding energy (BE) values were observed to shift toward the lower BE side for increasing aluminum content. Raman spectra were obtained for the undoped and Al doped ZnS films, which exhibit first-order phonon modes at 328.33 cm−1 and 341.66 cm−1 for the A1/E1 longitudinal optical phonons, and the bands at 253.33 cm−1 and 263.33 cm−1 revealed longitudinal optical phonon–plasmon coupled modes. UV–visible spectrophotometric measurement showed that approximately 70%–80% transmission happened in the visible to near infrared region, with a direct allowed bandgap in the range of 3.52 eV–3.76 eV. A maximum transmittance of 80% was observed for 6 wt. % Al doped ZnS thin films, and the absorption edge shifted toward the blue spectrum region. ZnS and ZnS:Al thin films showed n-type electrical conductivity with carrier concentrations varying from 1.55 × 1017/cm3 to 3.13 × 1017/cm3. Resistivity of the ZnS:Al thin films was decreased with the increase in Al concentration.

Effect of Annealing Temperature on The Improved Photo Catalytic Degradation of Zinc Sulfide Thin Films Under Visible Light Irradiation

Here, we reported a modern sort of zinc sulfide thin films as a catalyst was prepared from simple sol-gel approach. The as-deposited samples were further annealed at 200, 300, 4000 C temperatures under atmospheric environment. The variation in the annealing temperature becomes crucial for optimizing the prepared samples characterization and dye degradation behavior. Structural and morphological analysis recommends that test were hexagonal crystal structure and spherical shaped morphology, particle size was found within the range of 25-40 nm. The significant red shift was found within the absorption edge and lessening of energy in the band gap was found whereas the annealing temperature is increased from 200 to 400 oC. Recombination of photo-generated electron-hole sets was moreover distinguished and the photo-degradation test was monitored methylene blue dye solutions under visible light irradiation. The 400 oC annealed sample showed superior photocatalytic performance such as high degradation efficiency and long term stability towards MB dye.

Effect of supporting electrolyte concentration on one-step electrodeposited CuInS2 films for ZnS/CuInS2 solar cell applications

A one-step electrodeposition process was used to obtain CuInS2 (CIS) films on a molybdenum substrate by varying the supporting electrolyte (lithium chloride, LiCl) concentration. The as-deposited samples were characterized by scanning electron microscopy, energy-dispersive spectroscopy, profilometry, and diffuse reflectance spectroscopy. From characterization, it was found that different concentrations of LiCl mainly lead to a morphological change in the obtained CIS films. Moreover, their chemical composition shifted to the stoichiometric composition for high concentrations of the supporting electrolyte. After annealing, the structural analysis from X-ray diffraction revealed that all samples crystallized in the tetragonal phase of CIS. In addition, it was found that the crystallite size increased for samples grown at higher concentrations of LiCl. Optical studies carried out by diffuse reflectance spectroscopy revealed that the band gap values increased from ~ 1.40 to ~ 1.45 eV (average) after the annealing process. Finally, zinc sulfide (ZnS) thin films were chemically deposited onto electrodeposited CIS films in order to evaluate the photovoltaic response of ZnS/CIS bilayer systems. We discovered that ZnS thin films covered the surface of CIS more effectively for the highest concentration of LiCl and that only the ZnS/CIS bilayer with the CIS film obtained at the highest concentration of LiCl showed a photovoltaic response.

Influence of Cu Thickness and Annealing on the Properties of ZnS/Cu/ZnS Multilayer Films

Zinc sulfide (ZnS), copper (Cu) and ZnS thin films were deposited sequentially on high-borosilicate glass by radio-frequency magnetron sputtering at room temperature, and a ZnS/Cu/ZnS sandwich structure was obtained. Cu thin films with thickness ranging from 4 to 20 nm were used as an intermediate metal layer. The effects of Cu thickness and annealing treatment on the surface morphology and the electrical and optical properties of the ZnS/Cu/ZnS multilayer films were observed. The results show that the surface roughness of the multilayer films was reduced with increasing Cu thickness. The conductivity and transmittance of the multilayer-structure device were regulated by tailoring the Cu thickness, illustrating that the 16-nm-thick Cu film is beneficial for obtaining high conductivity and transmittance performance. The structural properties of the multilayer films annealed at different temperatures were also studied. The annealed multilayers exhibited a cubic zinc blende structure with a highly (111)-textured orientation. The film crystallinity was improved with increasing annealing temperature.

Effect of concentration of trisodium citrate complexing agent on spray-synthesized ZnS thin films

Here, we present the effect of molar concentration of trisodium citrate complexant on the solid state attributes of zinc sulphide (ZnS) thin films grown using chemical spray pyrolysis (CSP). The films were synthesized using 0.1 M concentration of ZnCl2, 0.1 M concentration of thiourea with addition of 0.01 M, 0.02 M and 0.03 M concentrations of trisodium citrate complexant at 300 °C. The films’ transmittance, band gap, and refractive index are from 55.81% to 82.44%, 3.52 to 3.72 eV and 3.07 to 4.02 respectively. The films possessed cubic and microcrystalline/amorphous structures. The crystallite size of the film deposited with 0.01 M trisodium citrate concentration was 20.454 nm. The surface morphology exhibited separate standing nanodot-like and nanorod-like crystals with increasing molar concentration. Raman spectroscopy revealed CC bond. The Fourier transform infrared (FTIR) spectroscopy showed various bonds inherent in the film with an attendant band edge emissions arising from the photoluminescence (PL) studies. The contact angle disclosed the films’ hydrophilic surface characteristics.

Optical properties, microstructure, and multifractal analyses of ZnS thin films obtained by RF magnetron sputtering

The morphology, structure and optical properties of zinc sulfide (ZnS) thin films prepared through radio-frequency (RF) magnetron sputtering have been analyzed using atomic force microscopy (AFM), UV–Vis–NIR spectrophotometry, X-ray diffraction, and multifractal analyses. The X-ray diffraction patterns revealed that all ZnS thin films show a single peak at around 29.6°, which has been ascribed to the (111) planes of sphalerite phase, indicating that the growth direction of the films is the [111] direction. UV–Vis–NIR transmittance spectra were used to determine the refractive index of the samples, their thickness, and their band gap energy, showing the optical and semiconductor properties a clear dependence of the film thickness. Finally, ZnS thin films were characterized and analyzed by atomic force microscopy (AFM) measurements and multifractal analyses for a complex and precise interpretation of the 3-D surface microtexture characteristics. The multifractal examinations of the samples revealed a particular distribution at the nanometric level associated with multifractal surface characteristics. These experimental results are corroborated, presented, and discussed together with the essential stereometric parameters of the thin films. The combination of the different experimental information and the comprehensive stereometric and multifractal analyses provide new and deeper insight into the ZnS thin films that would be exploited to develop novel micro-topography models.

Analysis and characterisation of polycrystalline ZnS nanostructure

Zinc Sulfide (ZnS) thin films were deposited on glass substrates at the pressure of 10-6 mbar by thermal resistor evaporation technique. The effects of annealing on the structural and optical properties of ZnS films were studied. Polycrystalline ZnS films have been analyzed by X-ray diffraction. Only hexagonal phase with the preferred (111) plane was found in ZnS films. Optical characteristics were studied as a function of annealing temperature and film thickness in air. The results show that the energy band gap was found to be about 3.5 eV. It was observed that the energy gap decreases with the increase in the film thickness and increases with the increase in the annealing temperature.

Electrodeposited stoichiometric zinc sulfide films

Zinc sulfide (ZnS) thin films were obtained by electrodeposition on Hartford glass substrates using reduction potentials from −650 to −560 mV (vs. SCE), with a deposition time of 1000 s. The ZnS thin films were characterized after the annealing process using UV–Vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), under two atm, inert gas and sulfur gas, at two temperature conditions (150 and 250 °C). The ZnS thin films showed a hexagonal, homogeneous and uniform structure in the wurtzite phase with a band gap ranging from 3.71 to 3.82 eV. The morphology remained unchanged when the electrodeposition potential or the annealing temperature was varied. We obtained Zn/S ratio values of ~1 for the ZnS thin films under a sulfur atmosphere and under an inert atmosphere treated at 150 °C. The properties of the deposited ZnS thin films make them suitable for the development of photovoltaic devices based on Cu2ZnSnS4, either as a buffer layer in the back contact or as a precursor layer.

Investigations on the effects of rGO incorporation on the photosensitivity of (Cd:Zn)S nanocrystalline thin film-based visible photodetectors by hydrothermal synthesis

Reduced graphene oxide-incorporated cadmium zinc sulphide (rGO–CZS) thin films were synthesised on glass substrates by hydrothermal-assisted chemical bath deposition. The effect of the rGO concentration (0.5–2 wt%) on the photosensitivity of the films was established along with the structural, morphological and optical properties of the composite films. The structural investigations by XRD analysis ensured that the prepared samples are nanocrystalline with hexagonal structure of cadmium zinc sulphide. Scanning electron microscopy showed aggregated sphere-like CZS nanoparticles enveloped with rGO flakes. The average particle size attained from TEM image is approximately 8 nm. The presence of various functional groups was scanned by FTIR analysis. Further, we established the characteristics of the rGO–CZS nanocomposite films as visible-light photodetectors. The photosensitivity, photo response and detectivity of the devices were found to increase with rGO concentration. (2 wt%) rGO–CZS detector exhibits highest photosensitivity of the order of 106, photoresponse of 18.5 mA/W and specific detectivity of 2.08 × 1012 Jones. This work demonstrates fast and simple preparation process of rGO–CZS visible-light detectors with high sensitivity, responsivity and good stability. The enhancement of sensitivity and responsivity can be attributed to the excellent electron conductivity and mobility due to the warm interfacial contact between CZS nanoparticles and the rGO sheet.

Influence of argon pressure on the crystalline phase formation of RF sputtered zinc sulfide thin films

Zinc Sulphide thin films on quartz substrates, were deposited using RF sputtering with variable argon pressures, to assess its effect on the crystallinity and surface morphology. Structural analysis by XRD reveals the formation of crystalline ZnS films, with preferential growth along hexagonal (1 0 3) direction, at a low argon pressure of 0.02 mbar and preferential growth along cubic (1 1 1) direction, at an argon pressure greater than 0.02 mbar. It has been found that crystallinity, is improved at argon pressure of 0.1 mbar. An exponential decrease in film thickness & RMS surface roughness is observed, increasing argon pressure.

Characterization of Zinc Sulphide thin films prepared using RF-sputtering technique

Nanocrystalline Zinc Sulphide (ZnS) thin films were synthesized via RF magnetron sputtering technique on glass substrates. The influence of deposition parameters and post- deposition thermal annealing on the structural, morphological and optical properties was studied in detail. X-ray diffraction studies revealed the nanocrystalline nature of the films along with their crystalline perfection, indicated by the preferential orientation of the grains. Thin films were prepared with RF power ranging 100 W–250 W. The depositions were also performed for three different sputtering durations (10, 20, 30 min) with fixed RF power and also studied the effects of thermal annealing on the structural and optical properties of ZnS thin films. The films were characterized by x-ray diffraction (XRD), Scanning Electron Microscope and UV–Visible Spectroscopy.

A Comprehensive Review on Zinc Sulphide Thin Film by Chemical Bath Deposition Techniques

A Comprehensive Review on Zinc Sulphide Thin Film by Chemical Bath Deposition Techniques

Zinc(ii) and cadmium(ii) complexes, [M(iPr2P(X)NC(Y)NC5H10-κ2-X,Y)2] (X and Y = O, S), as single source precursors for metal sulfide thin films

Structural, morphological and optical studies of zinc and cadmium sulfide thin films with different contents of phosphorus.

The Influence of Substrate Temperature on Properties of Zinc Sulphide Thin Films Synthesized by Chemical Spray Pyrolysis

The Influence of Substrate Temperature on Properties of Zinc Sulphide Thin Films Synthesized by Chemical Spray Pyrolysis

Investigation of Mn doping concentration on the structural, optical, antimicrobial and dye degradation properties of ZnS thin films

The undoped and manganese (Mn) doped zinc sulphide (ZnS) thin film has been deposited on the glass substrate by sol gel dip coating method. The influence of different Mn concentration (Zn1−x Mnx S) (x = 0, 0.02, 0.04, 0.06, 0.08, and 0.1 wt%) on the structural, morphological, element composition , functional group and optical properties were investigated by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray, Fourier transmission infrared spectroscopy, UV–Visible spectroscopy and photoluminescence. In addition antimicrobial activity of as-deposited ZnS thin film has been evaluated by in vitro disk diffusion method against different microorganisms. Besides the photo catalytic degradation properties of methylene blue dye (MBD) and methyl orange dye (MOD) under UV light irradiation has been evaluated. From this investigation Mn doped ZnS thin film revelled excellent antimicrobial activity and photo catalytic degradation properties compare undoped ZnS thin film.