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The real-time photothermal degradation of methylene blue (MB) dye was studied using CuS thin film (TF) as a photocatalyst. The polycrystalline CuS TFs were fabricated on precleaned glass substrates by an aqueous solution of copper chloride and thiourea using a fully automated spray pyrolysis technique by varying temperatures (250–400°C). The properties of deposited films were studied by XRD, SEM, UV–Vis–NIR spectroscopy, photoluminescence (PL) and Hall measurement. XRD results show that the CuS TFs crystallized in the cubic phase with an average crystallite size ~22–30 nm. CuS TF grown at higher temperatures (350°C, 400°C) exhibited very low strain of about 0.55 and 1%, respectively. Hall study revealed that films deposited at 400°C had good electrical parameters with mobility (μ) of 0.866 cm2 V−1 s−1, Carrier concentration (p) of 5.21 × 1019 cm−3 and conductivity (σ) of 49.4 Ω-cm−1. The estimated optical bandgap of films were found to be in the range of 2.10–2.26 eV, revealing blue shift due to quantum size effects. The PL spectra showed two characteristic bands of the CuS films, at 422 nm and an intense green band at 504 nm. The copper sulphide TF showed high photocatalytic activities in a photo-decolourization of MB dye under irradiation of visible light, as CuS TF was able to completely decompose the dye in 160 min. [ABSTRACT FROM AUTHOR]

Copper sulfide (CuS) thin film was electrodeposited onto stainless steel (SS 316L) substrate under pulse potential control, from an aqueous acidic solution containing 10−3 M of CuSO4.5H2O and 10−2 M of SC(NH2)2. The solution pH was maintained at 2.2 ± 0.1 by adding a few microliters of 0.1 M H2SO4 solution. The electrodeposited thin film was grown at 30 °C by applying a forward potential (EF) of − 0.85 V vs Ag/AgCl for 0.2 s and a reverse potential (ER) of 0 V vs Ag/AgCl for 0.4 s. Cyclic voltammetry (CV) was used to determine EF and ER as well as the possible reactions that occurred in the studied system and to understand the electrochemical behavior of the SS 316 L substrate on the deposition solutions. Normal and grazing incidence X-ray diffraction (XRD), Raman spectroscopy, and energy-dispersive analysis of X-ray (EDAX) techniques showed that the obtained thin film, applying EF and ER, was a hexagonal covellite CuS. Scanning electron microscopy (SEM) analysis showed that the obtained CuS film is grainy and contained some cracks. Profilometry indicated that the elaborated film has a thickness of 7.85 ± 0.71 µm. Electrochemical impedance spectroscopy (EIS) and Mott–Schottky (MS) analysis were performed, but the results are controversial because of the participation of SS 316 L substrate in the behavior of the obtained data. [ABSTRACT FROM AUTHOR]

The thin films Fe doped copper sulphide Cu1−xFexS (CFS) (x = 0.01, 0.03, 0.05, and 0.07) were elaborated by spray pyrolysis deposition technique. The characterization by XRD and SEM of the thin films shows a Covellite CuS single phase without formation of other phases. The structure is a simple hexagonal with unit cell dimension, a = b = 3.79 Å and c = 16.34 Å. The Analysis of the UV–Vis spectra reveals that the energy band gap has been decreased from 2.47 to 1.98 eV with the increase of Fe concentration. The absorption coefficients of CFS films have increased from 1.155 × 105 to 1.712 × 105 cm−1. It has demonstrated that a right band gap with a right band edge alignment at a pH value for Fe-doped CFS can boost the material application as a photocatalyst for the visible light. According to this study, CFS (0.07) thin films for a pH = 3 solutions is a promising material for photocatalysis application for water splitting to hydrogen-oxygen production. Nevertheless, we demonstrate that the formation of straddling gap heterostructure for CuS and CFS for a pH solution between 7 and 8 induces the production of oxygen and hydrogen. [ABSTRACT FROM AUTHOR]

The thermal oxidation of CuS powder was examined under flow of nitrogen and dry air using thermogravimetry/differential thermal analysis. After 473 K, the oxidation of CuS occurred as a weight loss and accompanied with two overlapped exothermic peaks. The melting temperature delayed due to the formation of oxide and sulphate on the surface of the particles. X-ray diffraction revealed that the as-prepared thin films are mixed phases of hexagonal CuS, orthorhombic Cu2S and orthorhombic CuSO4. After annealing at 573 or 773 K, the films oxidized and new orthorhombic Cu8O phase appeared, and its intensity became dominant upon increasing the temperature and time. Nanoparticles morphology was observed for as-prepared films and upon annealing the nanoparticle became more rounded and bigger. The transmittance of the as-prepared films was almost zero over the entire measured range and it increased with increase in the annealing temperature and time, whereas the reflectance decreased. Both refractive and extinction coefficient values decreased with increase in annealing temperature and annealing time, while the bandgap virtually increased. The resistivity of the as-prepared film remained nearly constant until 543 K. Above 543 K the resistivity increased sharply. Negative and positive temperature coefficients in resistivity phenomena were explored in the annealed films and they were strongly dependent on both annealing temperature and time. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hole conducting, transparent CuS:ZnS thin films were produced via thermal evaporation. • A superior conductivity value of 1420 S/cm was obtained for (CuS) 0.49 :(ZnS) 0.51 films. • Proof-of-concept device of p+-(CuS) 0.49 :(ZnS) 0.51 /n-Si photodiodes were produced. • Photodiode exhibited an excellent photoresponsivity covering a wide spectral range. This study demonstrates the viability of the thermal evaporation method to produce transparent and highly conductive p-type (CuS) x :(ZnS) 1-x thin films by achieving the highest conductivity value (1.4 × 103 S/cm) reported in this field to date. This places it in direct comparison with n-type transparent conductors. Analysis through X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) unveils nanocomposite structures comprising sphalerite ZnS, chalcocite Cu 2 S, and covellite CuS nanocrystals in the thin films. The study reveals that transmittance values at a wavelength of 550 nm vary from 84 % to 65 % based on the increasing CuS ratio, establishing thermal-evaporated (CuS) x :(ZnS) 1-x thin films as promising candidates for p-type transparent electrodes. Moreover, p+-(CuS) 0.49 :(ZnS) 0.54 /n-Si heterojunction photodiodes were also produced. The heterojunction diode exhibited excellent photo-response characteristics in a wide range of wavelengths between 325 and 1170 nm at zero-bias. The responsivity value of the photodiode was as high as 1.44 A/W at the peak wavelength of 912 nm (9.45 mW/cm2) with a high I on /I off ratio of 1.45 × 104. Besides, it was shown to have excellent detectivity, response time, and external quantum efficiency (EQE) values corresponding to 2.62 × 1012 Jones, 8.45 µs, and 244 %, respectively. Most of these values are superior to those even in commercial-grade photodiodes. [ABSTRACT FROM AUTHOR]

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Copper sulfide (CuS) thin films were prepared on commercial glass substrates by Chemical Bath Deposition (CBD) method using solution of different copper salts at 50 °C temperature for seven hours. Different anions of copper salts that is crucial for the properties of the films affect the precipitation mechanism and growth rate. For this reason, the effect of the different copper salts on the properties of CuS thin films was investigated and discussed. The influence of the different copper salts in the chemical bath was determined by means of optical transmission of the thin films in the wavelength range of 400–1100 nm taken at room temperature. Next, using these data, the optical band gap values E g , the extinction coefficient k, the refractive index n , and the real ε 1 and imaginary parts ε 2 of the dielectric constant were calculated. The crystallographic structure of CuS thin films were analyzed with an X-ray diffractometer (XRD). XRD analysis was revealed the polycrystalline and hexagonal phase of CuS thin films. The surface roughness of the films were measured by AFM. The surface roughness of the thin films was different despite the same deposition time. [ABSTRACT FROM AUTHOR]

CuO and CuS films were coated on AISI 4140 steel samples by Successive Ionic Layer Adsorption and Reaction (SILAR) to investigate their usability as solid lubricant. Wear tests were performed using pin-on-disk tribo-tester under dry and lubricated conditions. The structural, morphological and morphological features of untreated, CuO and CuS coated samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and microhardness, scratch analysis. The surface examinations indicated that needle-like structures formed after coating processes and CuO and CuS films exhibited oleophobic behavior. CuO and CuS thin films reduced the coefficient of friction due to the low shear strength of bonding in transfer films. CuO and CuS films decreased the wear rates in comparison to untreated sample for both dry and lubricated conditions. Also, CuO thin films exhibited better wear resistance than CuS films in dry and lubricated wear tests. The overall results revealed that both CuO and CuS films produced by SILAR can be an alternative to conventional solid lubricants. [ABSTRACT FROM AUTHOR]

Copper sulfide (CuS) thin films with a nanoparticle structure on a fluorine-doped tin oxide (FTO) substrate prepared by facile chemical bath deposition (CBD) at different growth times were used as the CE for QDSSCs. The morphology of the CuS CE was controlled well by the electrochemical growth time. Here, the CuS thin films deposited for 2 h (CuS2h) CE and TiO2/CdS/CdSe/ZnS QD sensitized cell exhibited superior electrochemical and photovoltaic performance with Jsc, Voc, and FF values of 15.52 mA cm-2, 0.612 V, and 0.452, respectively, and an efficiency (η) of 4.29%, whereas the cell with the Au CE delivered an η of only 2.19% under the same conditions. Electrochemical impedance spectroscopy and Tafel polarization showed that the CuS film deposited at 2 h possesses fascinating electrocatalytic activity for the S2-/Sn2- redox couple in a polysulfide electrolyte solution that was superior to Au CE. In addition, the stability test conducted for both CuS and Au-based devices for approximately 45 h under the one sun illumination confirmed that the long-term stability of the CuS film decreased by 12% (4.31-3.79%), whereas that of the Au based cell decreased by 9.6% (2.19-1.98%) from 0 to 45 h. [ABSTRACT FROM AUTHOR]

A CuS thin film was prepared by the sulfurization of the electrodeposited copper layer on the FTO substrate using sulfur powder at 400 °C. Surface morphology and structure of the CuS thin film were investigated by scanning electron microscopy and X-ray diffraction. The surface morphology of the CuS thin film was worm-like with the diameter of 70 nm and its crystal structure was hexagonal. Band gap energy of the CuS thin film was obtained as 1.5 eV using absorption spectra. Photoelectrochemical response of the CuS thin film was analyzed under chopped illumination at negative and positive potentials. It showed photoelectrochemical response at negative potentials (ca. 2.6 μA cm −2 at −0.4 V vs. Ag/AgCl), but not at positive potentials, which confirmed its p-type semiconductivity. A ZnS thin film was synthesized by spray pyrolysis method and characterized using field emission scanning electron microscopy, X-ray diffraction and UV–vis spectrometer. It was shown that the surface morphology was smooth with the grain size of about 50–150 nm. Also, its crystal structure and band gap energy were hexagonal and 3.72 eV, respectively. In order to obtain PN (positive–negative) junction and increase photoelectrochemical response, the ZnS (n-type semiconductor) thin film was deposited on CuS (p-type semiconductor). Linear scan of elemental composition confirmed the presence of FTO, CuS and ZnS layers. Photoelectrochemical characterization showed more photoresponse than the CuS thin film at negative potentials (13.6 μA cm −2 at −0.4 V vs. Ag/AgCl) and no photoresponse at positive potentials. The results confirmed the synthesizing of PN junction at the interface of CuS and ZnS. [ABSTRACT FROM AUTHOR]

This work is focused on a systematic study of homogeneous growth of copper sulfide (CuS) thin films deposited under similar chemical deposition conditions and considering the variations of the number of dips during the chemical bath deposition process. The aim of this work is to investigate the influence on the structural, optical and electrical properties of CuS films when varying the deposition parameters aforementioned. The films were deposited at 27 °C during 45, 60, 75 and 90 minutes per dip. The CuS thin films presented an amorphous structure. The Raman spectra showed one band at 475 cm-1 (Eg) which corresponds to the CuS vibration. These notable characteristics are preserved in the samples obtained from all dips. The energy band gap values are in the range from 1.65 to 2.6 eV, the former value corresponding to the three dip process. The conductivity of CuS films increased as the grain size increased. These characteristics in CuS films make them suitable candidate for various semiconductor device applications, obtained by a rapid and low- cost technique. [ABSTRACT FROM AUTHOR]

Copper sulphide (CuS) thin films were grown upon Ti, indium tin oxide (ITO), and glass substrates by using spray pyrolysis deposition at 200°C. The films exhibited good adhesion compared to chemical bath deposition. CuCl·2HO and NaSO·5HO precursors were used as Cu and S sources, respectively. Two concentrations (i.e., 0.2 M and 0.4 M) were selected in this study. X-ray diffraction analysis reveals that the films with 0.2 M showed only the formation of a covellite CuS phase having a hexagonal crystal structure with diffraction peaks of low intensity. For 0.4 M concentration, in addition to the covellite CuS phase, chalcocite CuS phase having a hexagonal crystal structure also appeared with relatively higher intensity peaks for all thin films. Field-emission scanning electron microscopy observations showed the formation of small grains for 0.2 M, whereas a mixture of grains with square-like shape and nanoplates were formed for 0.4 M. Depending on the 0.2 M and 0.4 M thin films thicknesses (3.2 μm and 4 μm, respectively), the band gap energy was obtained from optical measurements to be approximately 2.64 eV for 0.2 M (pure CuS phase), which slightly decreased up to 2.56 eV for 0.4 M concentration. Hall effect measurements showed that all grown films are p-type. The 0.2 M film exhibited much lower sheet resistance ( R = 33.96 Ω/Sq-55.70 Ω/Sq) compared to 0.4 M film ( R = 104.33 Ω/Sq-466.6 Ω/Sq). Moreover, for both concentrations, the films deposited onto ITO substrate showed the lowest sheet resistance ( R = 33.96 Ω/Sq-104.33 Ω/Sq). [ABSTRACT FROM AUTHOR]

The p -CuS/ n -GaN heterojunctions were fabricated successfully using RF magnetron sputtering. It was found that the properties of CuS films with annealing treatment were superior to non-annealed ones through various tests of SEM, XRD, Raman, EDS, and absorption spectrum. The optical band-gap slightly increased after annealing treatment. The current-voltage ( I–V ) characteristics of p -CuS/ n -GaN heterojunction were measured and showed well-defined rectifying behavior for the annealed device. [ABSTRACT FROM AUTHOR]

Membrane thickness is a very important parameter in controlling the sensitivity of the pH sensor and its other behaviour, such as hysteresis, repeatability, stability and reliability. Therefore, in this research work the thickness of CuS membrane was studied to find its effects on these parameters. CuS membrane was prepared from copper chloride and sodium thiosulfate dissolved in deionized water and ethanol with the ratio (7:3) then deposited on glass substrates for 60 and 150 sprays, respectively using spray pyrolysis deposition. These thin films were exposed to Xray diffractometer and field emission scanning electron microscopy to recognize their structures and crystal shapes. Then they were used as pH sensors, so their sensitivity, hysteresis, repeatability, stability and reliability were measured. All obtained results confirmed that the membrane with low thickness (sensitivity, linearity and hysteresis 22.9 mV/pH, 93.8%, and 23.75 mV respectively) were much better than that of high thickness (sensitivity, linearity and hysteresis 7.5 mV/pH, 70.2%, and 41.37 mV respectively) as pH sensor. [ABSTRACT FROM AUTHOR]

In this work, copper sulphide (CuS) thin films were deposited on glass substrates by chemical bath deposition method under different pH, deposition temperature, stirring speed and deposition time. The effects of process parameters, such as pH from 1.8 to 2.2, deposition temperature from 30 to 50 °C, stirring speed from 50 to 250 rpm and deposition time from 8 to 40 h on the band gap, were optimized by central composite design (CCD) of response surface methodology (RSM). Five-level-four-factor CCD was employed to evaluate the effects of the deposition parameters on the band gap of CuS thin films. A quadratic model was established as a functional relationship between four independent variables and the band gap. Analysis of variance revealed that the proposed model was adequate. The optimum pH, deposition temperature, stirring speed and deposition time were found to be 2.10, 44.33 °C, 200 rpm, and 32 h, respectively. Under these conditions, the experimental band gap of CuS was observed as 2.74 eV, which was well in close agreement with predicted value (2.71 eV) by the model. [ABSTRACT FROM AUTHOR]

CuS thin films with various molar concentrations at 70 °C temperature were deposited by Chemical Bath Deposition. The effect of molar concentration on the structural, linear optic, nonlinear optic and morphological properties of CuS films were deeply investigated. X-ray diffraction (XRD) analysis exhibited that CuS films were formed in polycrystal structure and hexagonal phase. The fundamental optical parameters of films such as energy band gap, reflection and extinction coefficient were determined with the results of optical transmission and optical absorption by UV–vis spectrophotometer. The energy band gap values were reduced with increasing films thickness. Moreover, the dependence of the optical dielectric constants, loss tangent, optical conductivity, surface and volume energy loss function values on the molar concentrations were studied. Furthermore, the third order nonlinear optical susceptibility and nonlinear refractive index, which is considered to be the base of the first order optical susceptibility with nonlinear optical properties were discussed in detail. • Copper sulfide (CuS, covellite) thin films were prepared at various molar concentrations (0.1 M, 0.3 M, 0.5 M) at a temperature of 70 °C by Chemical Bath Deposition. • The energy band gap reduced with increasing the thickness of CuS thin films. • The refractive indices of the films obtained at 0.1 M, 0.3 M and 0.5 M at 550 nm were calculated as 2.31, 2.63 and 2.64, respectively. • It was determined that the first-order optical susceptibility values of CuS films varied in the range of 0.268–3.031 in the visible region. • The third-order nonlinear optical susceptibility values varied in the range of 8.75 × 10−10–1.44 × 10−5 esu. [ABSTRACT FROM AUTHOR]

Abstract: We have investigated room temperature sensing characteristics of CuO films to various gases i.e. Cl2, H2S, NH3, CH4, CO and NO. CuO films were prepared by oxidation of Cu films, which were deposited on polycrystalline alumina substrates by thermal evaporation technique. CuO films have been found to be highly selective towards H2S. We demonstrate that the H2S response of CuO films can be divided in to three regions: (a) low concentrations (100–400ppb), (b) intermediate concentrations (500ppb to 50ppm), and (c) high concentrations (>50ppm). For low concentrations (100–400ppb), the response curves have been found to be highly reversible with very small response (∼60s) and recovery (∼90s) times, indicating suitability of CuO films for sub-ppm sensing of H2S. Oxidation of H2S by adsorbed oxygen is found to be the responsible sensing mechanism. However, at very high H2S concentrations (>50ppm), surface of CuO grains is found to convert into CuS, resulting in an irreversible response curve. For intermediate concentrations (500ppb to 50ppm), the response curve is governed by both H2S oxidation and CuS formation mechanisms. [ABSTRACT FROM AUTHOR]

CdS/CuS and CuS/CdS thin films were deposited on glass substrates at room temperature by chemical bath deposition technique. The structural characterization was done using Philips PW 1800 X-ray diffractometer (XRD) while the absorption coefficient (a) together with the band gap were determined using the absorbance and transmission measurement from a Unico uv-2102 PC spectrophotometer, at normal incidence of light in the wavelength range of 200-1000nm. The results of the optical characterization of CdS/CuS heterojunction thin films were compared with optical properties of binary thin films of CdS and CuS. The results show a clear deviation in the optical properties of the stacks of CdS/CuS thin films from the individual binary films that make up the stacks. The plot of (ah?)2 against (h?) showed that the materials have direct band gap values 1.70, 2.00, 2.10 and 2.30 eV for CuS, CuS/CdS, CdS/CuS and CdS respectively. [ABSTRACT FROM AUTHOR]

Abstract: In this study, oriented CuS nanoplates standing perpendicularly on F: SnO2 (FTO) coated glass substrates have been prepared through a mild microwave assisted chemical bath deposition process in which copper acetate reacted with ethylenediamine tetraacetate acid disodium and thioacetamide in aqueous solution within 40min. The effects of reaction time and microwave radiation on the treatment process were investigated. The morphology, structure, and composition of the yielded nanostructures have been confirmed by X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), and scanning electron microscope (SEM). Also, the correlation between the reflectance, transmittance coefficient in the UV and the thickness of films was established. Furthermore, a two-point probe was used for resistivity measurements. We believe this simple chemical conversion technique can be further extended to the synthesis of other semiconductors with various morphologies. [Copyright &y& Elsevier]

Abstract: Copper sulphide thin films in the 90–300nm thickness range have been deposited on soda–lime glass substrates by thermal co-evaporation of Cu and S. Depending on the film thickness, the optical transmittance in the visible region is of about 50% for the thinnest film and 19% for the thickest film, with the corresponding near-infrared transmittance dropping from 11% to near-zero at 2500nm as the film thickness increases from 90 to 300nm. A resistivity of ρ ~10−4 Ω cm has been obtained for the films. The optoelectronic properties of the films remained practically unchanged after one year stored under laboratory ambient. The optical properties obtained for selected CuS-based films make them suitable for their use as effective solar control glazings in warm climates. [Copyright &y& Elsevier]

Abstract: CuS, Cu0.6Zn0.4S and ZnS thin films were grown by successive ionic layer adsorption and reaction (SILAR) method on glass substrates at room temperature. The annealing temperature effect on the crystal structure, optical band gap and the light effect on the electrical properties of these films have been investigated. Scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques were used for the investigation of structural properties of films. The SEM and XRD studies showed that the films are covered well with glass substrates and exhibit polycrystalline characterization. Using the absorption measurements, the band gap energies for CuS, Cu0.6Zn0.4S and ZnS thin films were found as 2.03, 2.14 and 3.92eV at room temperature, respectively. The two-point-probe method was used for the investigation of electrical properties of films and it was found that the current increase with increasing light intensity and increasing rate in illuminated 500Wcm−2 films was greater than in others. There is an important increasing in the current values of the CuS and Cu0.6Zn0.4S films which have annealed at 400°C. But the annealed ZnS thin film has less current values than the as-grown film. This is the first study which led to deposition of the CuZnS thin films by using the SILAR method. [Copyright &y& Elsevier]