Cadmium Sulfide Thin Films Research Articles

Synthesis and characterization of cadmium sulfide (CdS) thin films by cyclic voltammetry technique

Abstract Nanostructure (II-VI) semiconductor Cadmium Sulfide (CdS) have interesting due to their in scientific circle and varieties of encouraging potentials in extensive applications such as transparent windows, photoluminescence devices, sensors, solar cells, etc. In this work, nanocrystalline CdS thin films (TFs) synthesized on the Indium tin oxide (ITO) coated glass substrate via cyclic voltammetry (CV) with a three-electrode deposition technique. X-Ray Diffractometer (XRD) used for the structural study of TFs and the topographical image characterized by using an Atomic Force Microscope (AFM). XRD patterns of the TFs were shown that nanocrystaline in nature with a cubic structure at (2 0 0) as the preferential orientation. Chemical compositions of the deposited TFs analysed by using Fourier Transform Infrared Spectroscopy (FT-IR). The optical properties of CdS TFs characterized by using a UV–Vis spectrophotometer showed that the optical band gap energy (Eg) decreases from 2.92 eV to 2.28 eV with increasing of deposition time from 15 min to 60 min respectively. Urbach energy increases from 117 meV to 151 meV with increasing of deposition time from 15 min to 60 min respectively.

Effect of substrate temperature on thermally evaporated CdS/CZTS for solar cell fabrication

The metal chalcogenides has a potential application in energy harvesting systems due to the good optical absorption, much abundance and suitable band potentials. In view of this, n-type Cadmium sulphide (CdS) thin films were thermally evaporated on conducting glass substrate (patterned Indium doped Tin Oxide (ITO) substrates, Ossila S211) followed by the p-type Copper Zinc Tin Sulphide (CZTS) films using nanocrystalline CZTS which in turn was obtained by mechanosynthesis at different milling rates. The mechanosynthesized CZTS nanoparticles and its corresponding films obtained by thermal evaporation were subjected to various characterization techniques such as XRD, UV–Vis-NIR spectroscopy and Hall Effect Measurement techniques in order to understand its physical properties, to access the rate of absorbance and to determine the type of conduction. Moreover, n-CdS as well as p-CZTS films were deposited at different substrate temperatures and studied the effect of temperature on the structural and optoelectronic behaviour of the respective films toward the fabrication of heterojunction solar cells. Finally, the p-n heterojunction was formed using n-CdS/p-CZTS films on patterned ITO substrates.

Growth and characterization of copper cadmium sulphide thin films

Copper cadmium sulphide thin film was deposited onto glass (soda-lime) substrates using chemical bath deposition (CBD) technique at room temperature. Chemical, optical, structural, and microstructural features were examined via the Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), UV-Vis Spectroscopy, and High-resolution Transmission Electron Microscopy (HRTEM). FTIR revealed that the associated chemical bond was below the 900 cm-1 marks. The optical band-gap of 2.36 eV was estimated from the absorption analysis. X-ray diffraction measurements reveal that the deposited material is polycrystalline with hexagonal and cubic structures typical of the binary constituents of and thin films. The grain sizes were randomly distributed and ranged between 35 and 60 nm as indicated by the HRTEM.

Preparation of Multi-Wall Carbon Nanotubes/Graphene Composites with Cadmium Sulfide in Dye-Sensitized Solar Cells (DSSCs)

In the present work, Dye Sensitized Solar Cells (DSSCs) have been fabricated by utilizing a dense layer of photoelctrode cadmium sulfide thin film (CdS) as n-type, which prepared by spray coating, while p-type electrode was multi-wall carbon nanotubes/graphene (MWNT-G) composites. The experimental results showed the higher energy conversion efficiency for CdS/MWNT-G was 0.056% in comparison with the others, which were CdS/MWNT with 0.044% and CdS/G with 0.037% respectively, which referred to improvement in the conductivity by using MWNT-G. The microstructure and nanostructure of CdS, MWNT, G, and MWNT-G nanocomposite were carried out by employing Scanning Electron Microscopy (SEM). X-Ray Diffraction (XRD) has been used to get crystal size of CdS, Raman scattering, and optical absorption also used for characterizations the samples. This study promised to increase and enhance the conversion efficiency of photovoltaic devices.

Photocurrent Measurements in Cadmium Sulphide Thin Films

Photocurrent Measurements in Cadmium Sulphide Thin Films

Study of Selected Morphologic, Structural and Optical Effects of Silver Coated CBD-CdS Thin Films

This work focused on comparing cadmium sulphide (CdS) thin films with and without CdS silver aggregates (CdS:Ag) deposited on the surface. We report absorption and transmission responses. Using the Tauc method, we obtained direct band gap energies with values of 2.50 (CdS) and 2.49 eV (CdS:Ag). We performed a scanning electron microscope characterization at different magnifications were cluster formations with granular shapes were observed. The highest magnification of 50,000× showed silver clusters as shiny granulates, which were confirmed by microprobe elemental mapping at a magnification of 18,000×. Energy Dispersive Spectroscopy revealed that the light composition of the silver clusters was the unique difference from the CdS thin film. X-Ray Diffraction results only detected the hexagonal CdS pattern, but not that of silver. The crystallite size was of around 13 nm. A Surface-Enhanced Ramman Scattering effect was observed upon the silver coating of the CdS thin film at 293.3 cm–1.

Structural, surface morphological and optical properties and their correlation with the thickness of spin coated superior quality CdS thin film synthesized using a novel chemical route

Cadmium sulfide (CdS) is considered as a superior buffer/window layer in thin-film solar cells apart from its various applications. The thickness of the buffer/window layer that defines the interface between the absorber layer is very important and needs to be thoroughly investigated for optimized device performance, particularly when a novel synthesis route and deposition technique is used. This manuscript presents the investigation on the various structural, morphological, and optical parameters and their correlation with the thickness of CdS thin film synthesized using a novel thiol-amine cosolvent with the help of Triton-X 100 surfactant. Spin coating technique is used to deposit CdS thin-films having thicknesses ranging from 100 to 300 nm on a glass substrate. X-ray diffraction (XRD) exposed the polycrystalline nature of the CdS films. All the diffraction peak intensities were found to increase with the thickness. Structural parameters like dislocation density, lattice strain, and crystallites per unit area calculated from the XRD data were found superior to those parameters for CdS films synthesized through various chemical routes, and the parameters indicated a positive correlation of the degree of crystallinity on the thickness. Similarly,surface morphology and optical properties of CdS films that were investigated by the scanning electron microscope (SEM) and UV–VIS spectrophotometer, were also dependent on film thickness. These results show that CdS thin film with superior crystallinity can be synthesized using thiol-amine cosolvent along with the Triton-X 100 surfactant and deposited by low-cost spin-coating on glass substrate. Moreover, the thickness variation appeared to be a single tool for obtaining application-specific various properties of CdS thin-film.

Degradation of Methylene Blue Using Cadmium Sulfide Photoanode in Photofuel Cell System with Variation of Electrolytes

Methylene blue degradation carried out using cadmium sulfide (CdS) photoanode in photofuel cell (PFC) had been done. CdS synthesized by chemical bath deposition (CBD) on the FTO substrate was used as anode and platinum as a cathode in photoelectrochemical studies. Characterization of CdS thin film was done using EDX, XRD, SEM, Raman, UV-Vis absorption spectrophotometer as well as photocurrent test of the CdS thin film under illumination using potentiostat with the three-electrode system. The EDX result indicated the presence of CdS with an elemental composition of Cd rich. XRD showed the appearance of CdS crystals in cubic and hexagonal formations. SEM image of CdS gave results in the form of crystals of less than 1 mm. Raman spectrum showed the appearance of CdS peaks. The bandgap of CdS was estimated to be 2.38 eV, and the photocurrent test confirmed that the film had a property of n-type semiconductor. Application of CdS thin film as a photoanode in the PFC system using 100 mg/L methylene blue solution showed degradation up to 48% for 2.5 h using a 4 cm2 photoanode, and the maximum potential of 0.8 V was obtained with a photoanode area of 1 cm2.

Structural and Optical Properties of Sprayed Ba Doped CdS Nanostructure Thin Films

Pure and Barium doped Cadmium Sulphide (CdS) thin films are grown by the chemical spray pyrolysis (CSP) technique. The films are characterized using X-ray diffraction (XRD), UV-VIS spectroscopy and Atomic Force Microscope (AFM). The XRD shows that pure and doped films are polycrystalline. The average grain of films was found to increase with Barium doping. The optical investigation shows a small decrease in bandgap value for the doped films. The pure and 2% and 4% Ba doped films were found to have a bandgap of 2.43eV and 2.5 eV respectively.

Enhancement of the performance of CdS/CdTe heterojunction solar cell using TiO2/ZnO bi-layer ARC and V2O5 BSF layers: A simulation approach

This article presents the role of Bi-layer anti-reflection coating (ARC) of TiO2/ZnO and back surface field (BSF) of V2O5 for improving the photovoltaic performance of Cadmium Sulfide (CdS) and Cadmium Telluride (CdTe) based heterojunction solar cells (HJSCs). The simulation was performed at different concentrations, thickness, defect densities of each active materials and working temperatures to optimize the most excellent structure and working conditions for achieving the highest cell performance using obtained optical and electrical parameters value from the experimental investigation on spin-coated CdS, CdTe, ZnO, TiO2 and V2O5 thin films deposited on the glass substrate. The simulation results reveal that the designed CdS/CdTe based heterojunction cell offers the highest efficiency, η of ∼25% with an enhanced open-circuit voltage, Voc of 0.811 V, short circuit current density, Jsc of 38.51 mA cm−2, fill factor, FF of 80% with bi-layer ARC and BSF. Moreover, it appears that the TiO2/ZnO bi-layer ARC, as well as ETL and V2O5 as BSF, could be highly promising materials of choice for CdS/CdTe based heterojunction solar cell.

Spray pyrolysis deposited K@CdS nanostructured films and their characterizations for optoelectronic and 3rd order nonlinear optical applications

Cadmium Sulfide (CdS) is an excellent semiconductor for photonic devices and its optical and electrical properties are greatly affected by single element doping. In the current manuscript, the effect of potassium ion (K+) doping on linear and nonlinear optical traits of spray pyrolysis deposited CdS films was investigated. The X-ray diffraction (XRD) spectra reveal the increase of defects, decrease of crystallinity and crystallite size also change in growth orientation with K+ doping in CdS films. Moreover, the position of FT-Raman peaks was slightly blue shifted and morphology of films shows clusters of agglomerated CdS nanoparticles along with small size nanoparticles in the background as revealed from SEM images. The bandgap of K+-doped CdS films slightly broaden and shows improved transparency as compare to pure CdS films. The dielectric constants were found to be first decease for 2.5% wt. K+ doping and thereafter slightly increase for 5.0% wt. CdS films whereas optical conductivity decrease for all K+ doping concentrations. The photoluminescence intensity of CdS decreases and slightly blue shifted upon K+ doping, also a new emission band appears at 630 nm, indicating formation of new trap states in the bandgap of semiconductor. The 3rd order nonlinear properties elucidated through Z-scan technique reveals the increase of n2 and χ3 whilst decrease of β with increase of K+ content in CdS thin films.

Chemical deposition of CdS thin films in the hexagonal phase without annealing

Cadmium sulfide (CdS) thin films were produced using the chemical bath deposition method with thiourea as the source of sulfur (S). Cadmium chloride (CdCl2) (2.4 mmol), potassium hydroxide (KOH) (0.15 mol) and ammonium nitrate (NH4NO3) (0.16 mol) were dissolved in 100 ml deionized water. Thiourea was added to the final solution at intervals of 0, 1.5, 3.0, 6.0 and 9.0 min. The effects of delaying the addition of thiourea were investigated. The optical properties of cadmium sulfide thin films were determined using an ultraviolet–visible spectroscopy machine. It was found that the bandgaps of the films decreased as the delay time of adding thiourea increased. The structural properties of the cadmium sulfide thin films were obtained by X-ray diffraction. It was discovered that when the film was created with a delay time of 6 min, it had a hexagonal structure. Surface analysis of all the thin films was done with a scanning electron microscope. It was found that cracks and voids decreased as the delay time of the thiourea addition increased.

FABRICATION AND CHARACTERIZATION OF DYE-SENSITIZED SOLAR CELLS BASED ON MUREXID DYE AND INORGANIC CdS:Mn THIN FILMS

In this study, dye-sensitized solar cells (DSSCs) were designed utilizing Murexid dye as an absorbing material and manganese doped cadmium sulfide (CdS:Mn) thin films as transparent layers. The CdS:Mn thin films were synthesized on tin doped indium oxide coated glass substrates (ITO) at 90 ºC using chemical bath deposition method (CBD). The Mn-doping process was carried out at concentrations of 0%, 2%, 4% and 6% (in molar ratio of manganese ions to cadmium ions). The structural, morphological and optical properties of the CdS:Mn thin films were examined using x-ray diffractometer (XRD), atomic force microscope (AFM) and UV–visible absorption spectrometer. The effect of the nanoparticle size on the cell performance of DSSC was investigated by J-V curves. The results regarding electrical measurements indicated that the maximum efficiency of 3.40%. Our experimental results suggested that this heterojunction can be a good candidate for DSSCs.

Low thermal budget processing of CdS thin films

Cadmium Sulfide thin films were deposited on soda-lime glass substrates by chemical bath deposition technique at bath pH varying from 8 to 11. The films were annealed at temperature 120 °C for 5 min using radiative annealing. The best film coverage at thickness ~ 99 nm, with bandgap 2.15 eV and resistivity of 0.5x101 Ωcm was obtained at a bath pH 10.

Fabrication and characterization of CuO/CdS heterostructure for optoelectronic applications

This paper reports the fabrication of a CuO/CdS heterostructure and the characterization of its properties for optical sensing. Cadmium sulfide (CdS) and cupric oxide (CuO) films were deposited by spray pyrolysis and hydrothermal techniques in order to fabricate CuO/CdS heterojunction devices. The structural, morphological, and optical properties of the CuO and CdS thin films were analyzed using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and UV–vis spectroscopy. The concentration of the sulfur precursor, thiourea, was varied over a range from 0.01 to 0.06 M in the spray coating solution for CdS films, and 0.05 M was found to yield improved structural and optical properties. The prepared p-CuO/n-CdS heterojunction exhibited good optical sensing properties with excellent response and recovery speeds. A possible photosensing mechanism for the fabricated heterostructure is detailed using energy band diagrams. In addition, heterojunction properties, including the ideality factor and conduction mechanism are reported: a fabricated heterostructure diode showed a threshold voltage of 0.036 V and an ideality factor of 1.86.

Comparative study of binary cadmium sulfide (CdS) and tin disulfide (SnS2) thin buffer layers

Binary compound tin disulfide (SnS2) and cadmium sulfide (CdS) are the potential candidates used as a buffer layer for copper indium gallium selenide (CIGS) and copper zinc tin sulfide (CZTS) thin-film device. Herein, both compounds have been successfully prepared through simple hydrothermal (HD) and chemical bath deposition (CBD) techniques, respectively. The prepared samples were characterized by different available techniques like X-ray diffraction (XRD), atomic force microscopy (AFM), surface electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmittance electrons microscopy (TEM), UV–Visible spectroscopy and photoelectrochemical (PEC) analysis. The XRD analysis confirms the polycrystalline nature of the prepared thin films. AFM analysis showed that the SnS2 display better roughness (60 nm), grain size (75 nm) than CdS roughness (23 nm), grain size (41 nm) thin films. SEM and EDS studies revealed near stoichiometry behavior of elemental composition of the films. The optical absorption spectrum showed the direct bandgap of CdS 2.45 eV and 2.20 eV for SnS2 thin films. The PEC analysis revealed that the SnS2 thin films exhibit two times higher photoresponse (140 µA) as compare to CdS (80 µA) thin films. The SnS2 high photocurrent could be attributed to the small band gap and increase in grain size which can trap more incident light. Based on the results the SnS2 used as a buffer layer can be a good choice for an efficient photovoltaic device.

Optical properties of CdS nanocrystalline thin films in the abrupt phase transition from zinc blende to wurtzite

A set of cadmium sulfide (CdS) thin films was grown on glass substrates by the chemical bath deposition technique at different bath temperatures (Tb). A microwave oven was used to heat the precursor aqueous solution employed to prepare the films in the 60–97 °C interval. The average crystallite size of the CdS films lies in the 7–20 nm range, calculated from X-ray diffraction data. The diffraction patterns reveal that the crystalline structure of CdS nanoparticles is cubic zinc blende (ZB) for 60 ≤ Tb ≤ 93 °C, hexagonal wurtzite (WZ) for 95 ≤ Tb ≤ 97 °C, and ZB-WZ mix of phases for the critical temperature Tb ≅ 94 °C (Tbc). The mixture of both phases is supported by Transmission Electron Microscopy. The CdS films show preferred orientation along (111) and (002) directions for ZB and WZ, respectively. The optical properties reveal significant changes at Tbc, namely, the energy band gap, photoluminescence emission, and refractive index. The photoluminescence results show an additional band at the critical phase transition temperature due to the presence of a high-density Cd interstitial/vacancies, produced by the mix of phases. Furthermore, high-energy transitions above the conduction band also exhibit splitting due to the phase transition.

A Comparative Study on CdS Film Formation under Variable and Steady Bath-Temperature Conditions

The deposition temperature of the bath in chemical-bath-deposited cadmium-sulfide thin films can directly affect the optical, electrical, structural as well as morphological properties of deposited thin films. The reporting work discusses the properties of chemical-bath-deposited cadmium-sulfide thin films deposited under steady chemical-bath temperature conditions at both 40 and 80°C and compares with films formed under variable bath-temperature conditions by varying the temperature of the chemical bath from 40 to 80°C and 80 to 40°C while depositing. The optical, electrical, structural, and morphological properties of the deposited films were examined by using ultraviolet-visible spectroscopy, photo-electrochemical cell, Mott–Schottky measurements, grazing incident X-ray diffractograms, scanning electron microscopy, and profilometry. According to the results, films deposited under steady chemical-bath temperature conditions show better optoelectronic properties compared to the rest, while films fabricated at 40°C are the best.

Structural, morphological, vibrational, optical, and nonlinear characteristics of spray pyrolyzed CdS thin films: Effect of Gd doping content

This paper reports the preparation of cadmium sulfide (CdS) thin films using a nebulizer spray pyrolysis technique by varying gadolinium content in the range of 0–5 wt.%; their characterization is also described. In this study, the effect of Gd concentration on structure, vibrational, optical linear, and nonlinear properties is investigated. The XRD examination of undoped and Gd-doped CdS films shows the crystalline nature toward the (002) plane. Other important parameters, such as crystalline size (D), strain (ϵ), and dislocations density (δ), were evaluated by XRD, and these results are thoroughly discussed. The SEM studies show the morphology of grains. It was observed that the size of grains increased with an increase in doping concentration. Owing to Gd doping in CdS, the optical energy gap is observed to be lower than that of pure film, which is in the range of 2.416–2.283 eV. The linear and nonlinear properties of CdS: Gd films indicated that Gd doping affected optical properties. The observed enhancement in opto-electrical properties, changes in crystalline quality, and optical property enhancements are caused by an increase in Gd doping concentration.

Structural, optical and photocatalytic properties of pure and Pd-doped CdS thin films

Pure and palladium (Pd)-doped cadmium sulfide (CdS) thin films were deposited on glass substrate by successive ionic layer adsorption and reaction (SILAR) process with different doping concentrations. X-ray diffraction results confirmed the crystalline and hexagonal phase structure of prepared samples. The increase in the main diffraction peak (002) intensity with increasing Pd concentration revealed the substitution of Pd+2 with Cd+2 in the lattice. The crystallite size increased from 58.32 to 89.71 nm with Pd concentration. Morphology of the thin films shown that the average grain size increases by the agglomeration of nano-grains which become cluster of particles after Pd+2 incorporation. The energy bandgap of the CdS thin films is decreased from 2.44 to 2.37 eV with increasing Pd percentage. Photoluminescence (PL) spectra described that the pure and Pd-doped thin films show a broad PL emission peak associated to the transition of sulfur ion vacancy transfers to the valence band. Moreover, the Pd doping improved the film photostability as well as the photocatalytic degradation of methylene blue (MB).