CuS Thin Films Research Articles

Correlation of Seebeck coefficient and selenization temperature in CuSe thin films grown on glass substrate

Copper selenide is emerging as a promising thermoelectric material that has the ability to harvest electricity from heat. In the present research work, copper selenide thin films were grown on glass substrate using thermal evaporation deposition technique. The phase transition from cubic to hexagonal structure was achieved by the selenization of grown samples at different temperatures (250, 300 and 350 °C) for 2 h. The phase, morphology and thermoelectric properties of the selenized CuSe thin films were studied using different characterization techniques. It was observed that the structural, morphological, and thermoelectric properties of the samples were modulated by varying the selenization temperature. XRD results suggested that as grown sample possessed a cubic phase but it transformed into hexagonal phase by selenization process. It was observed that Seebeck coefficient, electrical conductivity and power factor were modulated with the selenization temperature with maximum value of power factor (3.0 × 10−5±0.5 W m−1C−2) was obtained at optimal selinization temperature.

Low-temperature growth of CuS thin film on flexible substrates for photodetection

Abstract The covellite phase of copper sulfide thin film (CuS), owing to its excellent electronic, optical, and chemical properties, has attracted enormous attention in cutting-edge research. This research work emphasizes a comprehensive study of structural, optical, morphological, and electrical properties of CuS thin film deposited by chemical bath deposition (CBD) technique on flexible polyethylene terephthalate (PET) substrate at different deposition temperatures, i. e. 25 °C, 40 °C, 55 °C, and 70 °C for fabrication of flexible photodetector. XRD and Raman studies depict presence of hexagonal covellite phase (CuS), where as the RMS roughness of CuS thin film increases with a rise in deposition temperature. The optical bandgap of CuS thin film gets reduced with a rise in deposition temperature. The optimized CuS thin film, deposited at 70 °C, has exhibited a homogeneous surface with RMS roughness of 13.72 nm, mobility of 25.09 cm2/Vs, and bandgap of 1.86 eV. The mobility of CuS thin film is found to be increased with the rise in deposition temperature. The flexible CuS photodetector, deposited at 70 °C, has shown better photoresponse characteristics, exhibiting the highest responsivity of 0.18 mA/W, detectivity of 1.39×108 Jones, and sensitivity of 173.25 % upon light illumination. The photocurrent established possesses an outstanding dependence on various intensities of illuminated light. Furthermore, the bending test of flexible CuS photodetectors reveals the absence of any sign of deterioration up to a bending angle of 30°. The CuS thin film-based photodetector device exhibits the optimized photodetector device with reproducibility and steady photoresponse after bending. This suggests that the Al/CuS-PET/Al photodetector device could be used in various wearable optoelectronic device applications.

Synthesize and Investigate Structural, Surface Morphology, Optical, and Electrical Characterization of Cu2Se Thin Films by Thermal Evaporation Technique

Synthesize and Investigate Structural, Surface Morphology, Optical, and Electrical Characterization of Cu2Se Thin Films by Thermal Evaporation Technique

Two Step Synthesis of CuS Thin Films via High Vacuum Sulphidation

In this study, synthesis of CuS thin films on soda lime glass (SLG) substrates has been investigated. The synthesis method is based on high vacuum post-sulphidation of Cu thin films deposited by rf. magnetron sputtering. Sputtering conditions have been optimized so as to reduce grain size for better diffusion of S atoms through grain boundaries. XRD pattern of the precursor Cu sample revealed fcc structure with an average crystallite size of 24 nm. Best sulphidation was obtained at 175 oC for 60 min. The crystallite size of CuS calculated from the dominant peak of (110) planes was approximately 48 nm while average grain size observed via SEM was about 400 nm. Raman spectroscopy confirmed CuS structure by scattering peaks at around 467-472 cm-1. Elemental mapping unveiled homogenous distribution of Cu and S atoms over the surface. According to EDS data, at% compositions of Cu and S were 51.6% and 48.4%, respectively. Moreover, SIMS investigation has demonstrated uniformity of S atoms through the thickness of CuS thin film. Although XRD, Raman, and EDS analysis have resulted in predominant formation of CuS structure, existence of Cu2S phase with a strong luminescence peak located at 1.8 eV was determined by PL spectroscopy.

Facile synthesis and characterization of Cu2Se thin films and self-powered p-Cu2Se/n-Si heterojunction with high-performance photoresponse

A facile, cost-effective, and scalable chemical vapor deposition technique was used to synthesize p-type Cu2Se thin films on glass and n-type Si substrates. Thorough characterization confirmed the films’ β-phase structure with the correct stoichiometric ratio and exceptional crystalline quality, exhibiting behavior akin to a degenerate semiconductor. Measurements unveiled a work function of 4.83 eV and a bandgap of 2.13 eV for Cu2Se. The fabrication of a p-Cu2Se/n-Si heterojunction was achieved by depositing the p-type Cu2Se thin film onto the n-type Si substrate. The resulting heterostructure displayed rectification behavior, and its energy band diagram resembled a Schottky diode. Further exploration into its photoelectric properties showcased the p-Cu2Se/n-Si heterostructure’s favorable self-powered attribute, characterized by fast, steady, reproducible, sensitive, and robust photoresponsive performance. Consequently, it proves highly suitable for applications in high-frequency photodetectors. Additionally, the p-Cu2Se/n-Si heterojunction’s photovoltaic power conversion efficiency exceeded the reported values of the CuO/Si and Cu2O/Si systems. Here, this study contributes significantly to the pivotal evaluation of p-Cu2Se/n-Si heterostructures for promising optoelectronic applications.

Effect of precursor pH on the electrochemically synthesised barium titanium sulphide (BaTiS) material for photovoltaic application

ABSTRACT In this study, we deposited the electrochemically synthesised barium titanium sulphide material for photovoltaic application on FTO glass and studied the effect of precursor pH. The thin films deposited with titanium-doped barium sulphide underwent examination for their optical, structural, electrical, and surface morphological properties. As the wavelength of the photon increased, the absorbance decreased. The Ti-doped CuS thin film had the highest absorbance value (0.79) at pH 4.60 and the lowest value (0.48) at pH 5.10. The films deposited at pH 5.10, 4.90, 4.80, 4.70, and 4.60 yielded data of 0.48, 0.56, 0.62, 0.73, and 0.79. The energy band gaps for the thin films deposited at pH 5.1, 4.9, 4.8, 4.7, and 4.6 were 2.90 eV, 2.87 eV, 2.79 eV, 2.60 eV, and 2.42 eV, respectively. The film’s energy bandgap decreased as the bath pH decreased, as indicated by the results. The X-ray diffraction findings unveiled a cubic structural phase of barium sulphide, with a lattice constant of 6.3748 Å.

Impact of Cu2+ precursor on physical and photoelectrochemical properties of electrodeposited nanostructured CuS thin films for biosensor applications

Nanostructured CuS films were synthesized on FTO substrates employing low-cost electro deposition technique. XRD, Raman, SEM, UV–visible spectroscopy, photocurrent, PL, Mott-Schottky, and electrochemical impedance spectroscopy (EIS) measurements were used to examine physical and photoelectrochemical properties of samples. XRD results indicated that CuS films have hexagonal crystal structure where the crystallite size raises from 32 to 53 nm with increasing the Cu2+ molarity. Raman results displayed two peaks at 270 and 450 cm−1 that related to A1g transverse optical mode (TO) and A1g longitudinal optical (LO) mode for the vibrations of the S–S stretching and Cu–S bonds, respectively. SEM images displayed that fabricated CuS cover the substrate surface entirely, where grains are distributed uniformly with increasing the Cu+2 molarity. UV–visible measurements exhibited an absorption band edge between 450 and 550 nm as a characteristic of CuS films direct band gap. PL results presented strong blue-green emission at about 500 nm for CuS thin films. The photocurrent studies demonstrated that the CuS films are p-type semiconductors where the current density increases from 0.8 mA/cm2 to 1.1 mA/cm2 with the Cu2+ molarity increasing. The EIS analysis confirmed that charge transfer resistance reduces with increasing molarity. Mott- Schottky measurements established that carrier concentrations and the flat band varied from 5 × 1019 to 6.7 × 1019 cm−3 and from 1.1 to 0.75V, respectively. The fabricated CuS film was tested as glucose biosensor where a fast response and higher stability were noticed. Our results indicated that nanostructured CuS films are gifted candidates for optoelectronics applications especially biosensors.

Dual solution synthesis of Al doped CuS thin films for optoelectronic and photovoltaic applications

Dual Solution Synthesis (DSS) was used to deposit CuS doped with Al. The Samples were subjected to annealing under varying temperatures of 319K and 373K . The thin films were firmly adherent to the substrates. The optical properties were measured using UV -1800 series double beam spectrophotometer. The transmittance is from 0.3% to 0.6% while the reflectance is between 0.176 to 0.204, as the wavelength ranges from 320nm to 1000nm; the average band gap obtained is 2.6. The thicknesses achieved are 100nm and 124 nm. Other Optical properties were determined for each sample which makes it suitable for applications in optoelectronic, solar energy conversions, solar cells, thin film absorbers, anti- reflective coating, aesthetic windows, UV filter and other uses.

Effect of triethanolamine complexing agent and thermal annealing on the physicochemical properties of CuS thin films

Effect of triethanolamine complexing agent and thermal annealing on the physicochemical properties of CuS thin films

Transparent and flexible thermoelectric thin films based on copper sulfides

As a promising thermoelectric material, CuS has attracted significant attention due to its high conductivity, abundance of elements, and eco-friendliness. However, the study on CuS-based thermoelectric thin films is still lacking, impeding the advancement of CuS-based thermoelectric devices. Herein, high-quality CuS thin films have been fabricated through a facile vulcanization process. The effects of vulcanization temperature and film thickness on the thermoelectric properties of CuS thin films have been investigated. An optimal high power factor of 73.25 μW/m−1 K−2 is found at 400 K for a 20 nm-thick sample, and the optical transmittance is over 80% in the visible light spectrum. Meanwhile, excellent flexibility of the CuS thin films has been demonstrated. These results demonstrate the high promise of CuS thin films for transparent and flexible thermoelectric device applications.

Optimizing thermoelectric power factor in magnetron sputtered Cu2Se thin films by varying substrate temperature and synergy of Cu/Se ratio

Copper selenide (Cu2Se) is recognized as a p-type thermoelectric (TE) semiconductor known for its eco-friendliness, abundance in the earth's crust, and cost-effectiveness. Current research on Cu2Se primarily centers around its exceptional TE capabilities in bulk materials. However, two-dimensional thin films hold distinct advantages in TE micro- and nano-device development and applications. In the present study, a series of Cu2Se thin films were deposited on a glass substrate by employing radio frequency magnetron sputtering deposition by varying the substrate temperatures (Ts) from 50 °C to 400 °C with an interval of 50 °C. The impact of Ts role on the structural, microstructural, and electrical transport characteristics of Cu2Se thin films was investigated using the Grazing Incidence X-ray diffraction, High-Resolution transmission electron microscopy, Field Emission Scanning Electron Microscopy, and Seebeck analysis. The change in the Ts increased grain growth as observed from microstructure studies and improved electrical and transport characteristics. Notably, films deposited at Ts 350 °C exhibited a significant power factor of 16.8 μW/cmK2 at 450 °C, making them highly promising for TE applications.

Evaluation of substrate temperature role on the structural, morphological, optical, and mechanical properties of magnetron sputtered Cu2Se thin films

Copper Selenide (Cu2Se) thin films were deposited on a float glass substrate using magnetron sputtering with a radio frequency (RF) source at a power of 70 W and by varying substrate temperatures (Tsub) from 50 °C to 400 °C with an interval of 50 °C. The influence of the Tsub on the morphological, structural, and mechanical characteristics of Cu2Se thin films was investigated using the Grazing Incidence X-ray diffraction (GIXRD), Raman spectra, Field Emission Scanning Electron Microscopy (FESEM) combined with energy-dispersive spectroscopy (EDS) and Nanoindentation. The results of the GIXRD analysis suggest that the cubic Cu2-xSe phase could be observed when the deposition took place at Tsub of 50 to 200 °C. However, for the films that were deposited at temperatures higher than this range, i.e., from 250 °C to 400 °C, the elements Cu and Se formed an intermediate phase. Raman bands assigned at 261 cm−1 confirm the cubic-Cu2Se phase. The average grain size measured from FESEM images increase with varying Tsub from 50 °C to 400 °C with a value of 230 nm to 320 nm. The variation in the Tsub results in the evolution of the microstructure and EDS shows the variation in the stoichiometric ratio of deposition. The energy of the band gap decreases with an increase in Tsub, leading to the overlapping of energy levels. The nanoindentation tests show that the hardness dropped as the Tsub increased from 50 °C to 400 °C. The Cu2Se film deposited at Tsub 50 °C had the highest hardness value of 1.91 ± 0.47 GPa.

Investigating the Effect of Ph Variation on the Optoelectronic and Structural Properties of Electrodeposited Copper Selenide Thin Films.

Copper Selenide (CuSe) thin film compound semiconductors have been deposited onto fluorine doped tin oxide (FTO) conducting substrates using electrodeposition technique through various electrolytic bath pH values of 2.00, 2.20, and 2.40. The deposition was carried out in potentiostatic mode using a 2-electrode system set-up at room temperature for 15 minutes at the cathodic voltage of 500 mV. The electrical and the optical properties of the thin films were carried out using photoelectrochemical (PEC) cells and ultraviolet visible spectrophotometer respectively. CuSe thin film possesses a p-type electrical conductivity and the sample grown at semiconductor and a pH of 2.2 was recorded to have the highest PEC signal and highest photo and dark currents that brings forth its maximum power. The energy band gap values of the electrodeposited CuSe thin films were observed to be 2.30 eV, 2.20 eV, and 2.00 eV at bath pH values of 2.0, 2.2, and 2.4 respectively. The optical band obtained at the various pH decreases as pH increases and these band gap values agree with the bulk band gap of CuSe. The preferred orientation peak of electrodeposited CuSe layers exists as klockmannite (CuSe) and the highest peak intensity for the preferred orientation peak occurred at pH of 2.20. At this pH value, the electrodeposited CuSe layers have the highest crystallite sizes.

Investigating the Effect of Ph Variation on the Optoelectronic and Structural Properties of Electrodeposited Copper Selenide Thin Films.

Copper Selenide (CuSe) thin film compound semiconductors have been deposited onto fluorine doped tin oxide (FTO) conducting substrates using electrodeposition technique through various electrolytic bath pH values of 2.00, 2.20, and 2.40. The deposition was carried out in potentiostatic mode using a 2-electrode system set-up at room temperature for 15 minutes at the cathodic voltage of 500 mV. The electrical and the optical properties of the thin films were carried out using photoelectrochemical (PEC) cells and ultraviolet visible spectrophotometer respectively. CuSe thin film possesses a p-type electrical conductivity and the sample grown at semiconductor and a pH of 2.2 was recorded to have the highest PEC signal and highest photo and dark currents that brings forth its maximum power. The energy band gap values of the electrodeposited CuSe thin films were observed to be 2.30 eV, 2.20 eV, and 2.00 eV at bath pH values of 2.0, 2.2, and 2.4 respectively. The optical band obtained at the various pH decreases as pH increases and these band gap values agree with the bulk band gap of CuSe. The preferred orientation peak of electrodeposited CuSe layers exists as klockmannite (CuSe) and the highest peak intensity for the preferred orientation peak occurred at pH of 2.20. At this pH value, the electrodeposited CuSe layers have the highest crystallite sizes.

Real-time photothermal degradation of methylene blue dye by CuS thin film grown using a fully automated spray pyrolysis

Real-time photothermal degradation of methylene blue dye by CuS thin film grown using a fully automated spray pyrolysis

Improved thermoelectric power factor of multilayered poly(3,4-ethylenedioxythiophene) polystyrene sulfonate and Cu2Se thin films

Cu2Se is a promising thermoelectric material due to its superionic behavior with superior transport properties. Here we report a facile method of spin coating for the fabrication of multilayers of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and Cu2Se thermoelectric materials for mid-temperature range applications. The synthesis of multilayered thin films with a unique organic-inorganic hybrid framework could be used in flexible thermoelectric devices. The detailed investigation of PEDOT:PSS and Cu2Se multilayered thin films reveals interaction between organic and inorganic material as inferred by AFM and FTIR. The electronic transport properties were investigated for all specimens, with the highest PF of 20.1 µW/m. K2 at 450 K was achieved from the bilayer stacking of Cu2Se and PEDOT:PSS, which is about 82 % higher as compared to that of pure PEDOT:PSS at the same temperature. These improved transport properties are the combined effect of energy filtering and interface effects. The proposed strategy opens up an avenue for research on chalcogenide based composite materials with an organic framework for flexible thermoelectric device applications.

Homogeneity- and Stoichiometry-Induced Electrical and Optical Properties of Cu-Se Thin Films by RF Sputtering Power.

P-type Cu-Se thin films were deposited on glass substrates at room temperature using radio frequency magnetron sputtering by a single multi-component CuSe2 target. When using a multi-component target, the impact of the sputtering power on the homogeneity and stoichiometry within the thin films should be investigated in the depth direction to demonstrate a secondary effect on the electrical and optical properties of the thin films. Systematic characterization of the Cu-Se thin films, including the morphology, microstructure, chemical composition, and depth-directional chemical bonding state and defect structure of the thin films, revealed that the sputtering power played an important role in the homogeneity and stoichiometry of the thin films. At very low and very high sputtering power levels, the Cu-Se thin films exhibited more deviations from stoichiometry, while an optimized sputtering power resulted in more homogenous thin films with improved stoichiometry across the entire thin film thickness in the X-ray photoelectron spectroscopy depth profile, despite showing Se deficiency at all depths. A rapid decrease in carrier concentration, indicating a reduction in the net effect of total defects, was obtained at the optimized sputtering power with less deviation from stoichiometry in the Cu-Se thin films and the closest stoichiometric ratio at an intermediate depth.

CuS thin films coated with bioglass 45S5/TiO2 Nps and CuS/Zeolite ZMS5/1.5 [Ti] for urea biosensing applications

CuS thin films coated with bioglass 45S5/TiO2 Nps and CuS/Zeolite ZMS5/1.5 [Ti] for urea biosensing applications

Chemical vapor reaction synthesis and photoelectronic properties of CuS and Cu3SbS4 thin films

Chemical vapor reaction is a simple and efficient experimental means of preparing metal sulphide films. Through systematically studying the effect of vulcanisation temperature on the growth of copper sulfide (CuS) thin film. The copper antimony sulfide (Cu3SbS4) thin film was obtained by further vulcanized Sb/Cu mental film. The structure and optical properties of the as-prepared films were characterized by x-ray diffraction, Raman and photoluminescence spectra. The hexagonal structure of CuS film was confirmed and Cu3SbS4 grew preferentially along the (112) crystal plane. The surface grains of CuS and Cu3SbS4 films were finally condensed into spheres. The content of S and the resistance of the films increase with the increase in temperature, but the bandgap of the films will be decreased. The bandgap of Cu2−xS films prepared at 195 °C−350 °C is in the range of 2.2–2.5 eV and that of Cu3SbS4 thin films prepared at 350 °C is 1.77 eV, and has good absorption in the visible light range. In addition, The Hall effect measurement indicated CuS and Cu3SbS4 films have p-type semiconducting behavior. The carrier concentration and mobility are 2.45 × 1021 cm−3 and 1.28 cm2 Vs−1 for CuS, and 4.30 × 1017 cm−3 and 185.93 cm2 Vs−1 for Cu3SbS4, respectively. The I-T tests show that the CuS and Cu3SbS4 thin films have photoconductive properties.

Effect of annealing time on copper selenide thin films prepared by chemical bath deposition

Copper selenide (Cu2Se) thin films have been deposited on glass slide substrates using the chemical bath deposition technique at room temperature. The films were annealed at 250 °C in an air atmosphere at different time intervals. The X-ray diffraction revealed that the Cu2Se films have a face-centered berzelianite cubic structure. The estimated average crystallite sizes were found to be 45 nm. X-ray Photoelectron Spectroscopy showed binding energy peaks corresponding to the Cu2Se. Scanning electron microscopy results showed that the morphology of the Cu2Se thin films consists of spherical particles. Energy dispersive spectroscopy confirmed the presence of Cu and Se. The Ultraviolet–visible spectroscopy results showed that the energy bandgap of the films ranges between 1.52 and 1.25 eV. Photoluminescence results showed emissions from the Cu2Se defects at around 2.27, 2.40, 2.68, and 2.96 eV. It was found that the emission intensity increased up to 3 h and then decreased with an increase in annealing time.