Cadmium Sulfide Thin Films Research Articles

Thermally Induced Enhancement of Photoresponse in Radio Frequency‐Sputtered CdS Thin‐Film Photodetectors

This work focuses on understanding the defect‐related electronic transport in cadmium sulfide (CdS) thin films, and finds thermal treatment as an efficient tool to tailor its intrinsic defect charge carrier concentration for optimum visible‐light photodetection performance. The radio frequency (RF)‐sputtered CdS thin‐films show a substantial decrease in measured dark‐current by three orders of magnitude (μA to nA) with an increase in substrate deposition temperature (Ts) from room‐temperature (RT) to a maximum of 400 °C. With increase in Ts, the current conduction behavior changes from Ohmic (at RT) to Schottky‐behavior (Ts ≥ 100–400 °C). The decrease in dark‐current and the crossover from Ohmic to Schottky electronic transport behavior, pointed to a decrease in defect‐density charge carrier concentration, with increased Ts. Additionally, post‐deposition thermal annealing of CdS thin films also is found to result in a similar decrease in dark‐current (μA to nA). The photo‐to‐dark‐current ratio of CdS thin‐film visible‐light photodetectors increased by two‐orders of magnitude, and its dynamic response time decreased by an order of magnitude via. thermal engineering. The thermal‐annealing treatment possibly reduced the defect‐related trap‐sites, which enables a reliable and faster photo‐switching response for CdS thin‐film‐based visible‐light photodetectors.

Potentiostatic electrodeposition of copper, indium, and cadmium sulfides for CO2 electroreduction: A path toward sustainable hydrogen generation

This study focuses on the potentiostatic electrodeposition of copper indium and cadmium sulfide (CuS, In2S3, and CdS) thin films on copper substrates, aiming to develop efficient electrocatalysts for the electrochemical reduction of CO2 and sustainable hydrogen generation. Utilizing Cu Kα radiation for X-ray diffraction (XRD) analysis, the crystal structures of the electrodeposited films were confirmed, revealing well-defined crystalline phases. The films exhibited average particle sizes of 55.99 nm for CuS, 50.37 nm for In2S3, and 63.51 nm for CdS. Cyclic voltammetry and chronoamperometry were employed to optimize the deposition parameters, ensuring efficient nucleation and growth of the metal sulfide films. The electrochemical performance of the synthesized electrocatalysts was rigorously tested, demonstrating their potential for CO2 reduction under optimized conditions with the highest efficiency for CdS electrodes. Additionally, the electrodeposited CuS and CdS are of the p-type, and In2S3 is of the n-type semiconductor were studied and verified by the Mott–Schottky test. CuS, In2S3, and CdS were found to have donor and acceptor concentrations (ND) of 1.68 × 106, 1.44 × 105, and 8.9 × 105 cm3, respectively. The photoelectrochemical measurements of the electrodeposited metal sulfides were studied at ambient temperature and under illumination, providing higher photocurrent responses for CdS and demonstrating its strong potential as a photoelectrode material for CO2 reduction. This work underscores the significance of facile electrochemical synthesis methods in developing cost-effective and scalable electrocatalysts, paving the way for their integration into photoelectrochemical systems for green energy applications.

Study of structural, morphological and optical properties of flash evaporated cadmium sulphide thin films

Cadmium sulphide thin films were successfully synthesized by the flash evaporation method under vacuum, then annealed at various temperatures. X-Ray Diffraction patterns showed the formation of the hexagonal wurtzite phase. Structural properties of this most stable phase remain approximately the same at all investigated temperatures. Scanning Electronic Microscopy showed the formation of granular films. The Energy Dispersive X-ray spectra revealed the possible formation of stoichiometric compounds. The obtained UV–Vis spectra revealed that the prepared films exhibit a moderate direct band gap with high transmittance in the visible range. Detailed interpretation of the structural, optical, and optoelectronic findings revealed that annealed CdS thin films hold promising potential for the fabrication of the next generation of the modern optoelectronic devices. Cadmium sulphide thin films were successfully synthesized by the flash evaporation method under vacuum, then annealed at various temperatures. X-Ray Diffraction patterns showed the formation of the hexagonal wurtzite phase for all temperatures with almost the same structural properties. UV–vis spectra revealed that the prepared films exhibit a moderate direct band gap with high transmittance in the visible range, which reinforces the usefulness of these films for photovoltaic and photocatalytique applications. Scanning Electronic Microscopy shows the formation of granular films, while the Energy Dispersive X-ray spectra revealed the possible formation of stoichiometric compounds.

Fabrication and Characterization of Graphene Oxide – Cadmium Sulphide Nanocomposite Coating for Corrosion Inhibition of Mild Steel Specimen

Abstract The oil and gas sector play a significant role in the Sultanate of Oman’s economic growth and contribute major revenue. Corrosion is a global concern and that strongly affects the industrial sectors. The corrosion problems in oil pipelines would be successfully resolved by means of novel control techniques. This research focused on the fabrication of Graphene oxide (GO) - Cadmium sulphide (CdS) nanocomposite for controlling corrosion in mild steel specimen. Graphene oxide was synthesized from Alovera extract by carbonization process. GO - CdS nanocomposite was prepared and deposited on a mild steel pipe by self-assembly technique. The coated material was used for stability studies at varying pH conditions and exposure period followed by corrosion studies. The testing methods adopted are Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Energy Dispersive X-Ray analysis (EDX), and Fourier Transform Infrared Spectroscopy (FTIR). Wet/Dry test and Atmosphere tests were conducted to examine the performance of coating material towards corrosion. The atomic force microscope (AFM) operated in non-contact mode was used to study surface topology of the coated specimen. From the outcome of the corrosion studies, it was established that the GO- CdS Nano composites thin film acted as an ecofriendly corrosion inhibitor to enhance the lifespan of the mild steel pipe. This novel research is aligned with the United Nations Sustainability Goals (UNSD - 9: Industry, Innovation and Infrastructure & UNSDG 12 – Responsible consumption and production) and Oman vision 2040. The results from the study validates that the GO - CdS thin films coated on mild steel pipe could be a viable solution to corrosion issues in oil pipelines owing to their good film stability, minimum film thickness, high durability, and ecofriendly approach.

ZnS and CdS nano thin films – A comprehensive analysis of structural, morphology and optical properties for photovoltaic applications

The current study is on the deposition of Zinc Sulfide and Cadmium Sulfide thin films by chemical bath deposition (CBD) technique. The deposited films were annealed at 200 °C and 350 °C in vacuum system. The Structural, Surface morphology, elemental composition and Optic analysis were performed by XRD, SEM, EDX, PL and optical transmission spectra. The XRD confirmed the formation of ZnS and CdS which revealed a broad spectrum in the low 2θ region due to its amorphous behaviour. The average optical transmission spectrum of ZnS lies between 65 % and 80 % and CdS lies between 50 and 60 %. The optical band gap of both the annealed films was decreasing with increase in temperature. The higher optical transmittance observed from emission spectra of PL analysis can contribute better performance and proved that the annealed ZnS and CdS thin films are applicable for photovoltaic applications.

Synthesis and Characterization of a Semiconductor Diodic Bilayer PbS/CdS Made by the Chemical Bath Deposition Technique.

In this work, we report a heterojunction formed by a PbS/CdS bilayer using the chemical bath deposition (CBD) technique because it is a relatively simple, fast, and low-cost technique; is permitted to obtain high-quality thin films (TFs); and also covers large areas. Some characterizations have been carried out to confirm the identity of the involved bilayer. For the cadmium sulfide (CdS) film, optical properties such as absorption, transmission, reflection, extinction coefficient, and refractive index were measured. Moreover, the bandgap was calculated, and morphology was obtained by scanning electron microscopy (SEM). Also, X-ray diffraction (XRD) and high-resolution transmission electron microscopy (TEM) were performed for the synthesis of CdS films. On the other hand, for the synthesis of lead sulfide (PbS) films, we performed TEM, energy-dispersive spectroscopy, and XRD. A surface morphological SEM image of the PbS film synthesized was also taken. The multiheterojunction PbS/CdS bilayer was characterized by the current-voltage (I-V) curve, and the behavior of the bilayer was evaluated under the conditions of darkness and controlled fixed lighting, detecting a very slight photosensitivity of the complete diodic device through those measurements. The calculated bandgap for the CdS TF was E g = 2.55 eV, while after a chosen thermal annealing, the bandgap decreased to 2.38 eV. On the other hand, the PbS film presented a cubic structure.

Elaboration and Characterization of CdS Nanostructures Using Pulse‐Assisted Electrodeposition: Effect of Time‐Off Duration

The presence of metallic cadmium in the electrodeposited cadmium sulfide (CdS) films is a persistent problem that leads to low photoactivity. Changing the deposition mode is a way to address this problem and thus increase the photoelectrochemical performance. Herein, the effect of the deposition mode on the composition of the CdS films prepared under the same deposition parameters is investigated for the first time. In addition, the influence of the time‐off duration on the properties of the electrodeposited thin films is studied. The results of the X‐Ray diffraction, UV–vis spectroscopy, atomic force microscopy, and photoelectrochemical characterizations reveal that the pulse‐deposited CdS films show enhanced microstructural, optical, and morphological properties as compared to that of the film deposited under direct mode. The CdS thin film deposited at time‐off duration of 0.5 s is composed of a pure CdS phase following a mixture of cubic and hexagonal lattice structure. This sample shows a smooth surface, high absorption in UV and visible light and an intense photoresponse of 90 μA under visible light.

Surface-enhanced Raman scattering to realize the phonon processes in Ag nanoparticles-decorated CdS thin film

Abstract Surface-enhanced Raman spectroscopy (SERS) technique can achieve an ultra-high sensitivity (i.e., down to the single-molecule level) via coinage-metal nanostructures such as silver, gold, copper, etc. In this work, a geometry is proposed that consists of silver nanoparticles (AgNPs) decorated on cadmium chloride (CdCl2) annealed cadmium sulfide (CdS) thin film on a glass substrate. A strong SERS enhancement in AgNPs on CdCl2 annealed CdS thin films is achieved, which is twelve times larger than the scattering from the bare CdCl2 annealed CdS thin film. The improved SERS signal allows us to observe fundamental phonon processes in CdCl2 annealed CdS thin film. Moreover, a finite difference time domain (FDTD) method is used to understand the underlying SERS physics. By using the FDTD method, robust electromagnetic field localization in the nanogap between AgNPs and at the contact point of Ag NPs and CdS thin film is studied.

A Role of Growth Potential to Enhance the Physical and Electrical Properties of Electrodeposited Cadmium Sulfide Thin Films

A Role of Growth Potential to Enhance the Physical and Electrical Properties of Electrodeposited Cadmium Sulfide Thin Films

A Role of Growth Potential to Enhance the Physical and Electrical Properties of Electrodeposited Cadmium Sulfide Thin Films

A Role of Growth Potential to Enhance the Physical and Electrical Properties of Electrodeposited Cadmium Sulfide Thin Films

Effect of substrate temperature and oxygen plasma treatment on the properties of magnetron-sputtered CdS for solar cell applications

Cadmium sulfide (CdS) is an n-type semiconductor with excellent electrical conductivity that is widely used as an electron transport material (ETM) in solar cells. At present, numerous methods for preparing CdS thin films have emerged, among which magnetron sputtering (MS) is one of the most commonly used vacuum techniques. For this type of technique, the substrate temperature is one of the key deposition parameters that affects the interfacial properties between the target film and substrate, determining the specific growth habits of the films. Herein, the effect of substrate temperature on the microstructure and electrical properties of magnetron-sputtered CdS (MS-CdS) films was studied and applied for the first time in hydrothermally deposited antimony selenosulfide (Sb<sub>2</sub>(S,Se)<sub>3</sub>) solar cells. Adjusting the substrate temperature not only results in the design of the flat and dense film with enhanced crystallinity but also leads to the formation of an energy level arrangement with a Sb<sub>2</sub>(S,Se)<sub>3</sub> layer that is more favorable for electron transfer. In addition, we developed an oxygen plasma treatment for CdS, reducing the parasitic absorption of the device and resulting in an increase in the short-circuit current density of the solar cell. This study demonstrates the feasibility of MS-CdS in the fabrication of hydrothermal Sb<sub>2</sub>(S,Se)<sub>3</sub> solar cells and provides interface optimization strategies to improve device performance.

Gamma radiation effect on the structural and optical properties of CdS thin films prepared by spray pyrolysis technique

One way to increase the solar cell efficiency is to increase the range of transmitted visible light throughout the window layer. This could be achieved via broadening its band gap; an aim that could be attained through doping and/or irradiation technique. In this way, cadmium sulfide (CdS) thin films have been successfully prepared on pre-heated glass substrates at 400 °C by spray pyrolysis technique and the effect of gamma radiation dose on the structural and optical properties of CdS thin films has been investigated in the range of 250 to 450 Gy. The XRD results manifest the formation of hexagonal phase of CdS with a crystallite size of 58.73 nm, which decreased to 47.26 nm after exposure to 350 Gy. Also, the SEM micrographs show the formation of some randomly oriented groups of nano-rods on the surface of highly condensed nanorods of CdS thin film. The optical investigation illustrates that a blue shift in the optical gap from 2.4 to 3.34 eV has been occurred as the radiation dose reached 350 Gy. The sensitivity of the films to the applied dose has approached 0.005 eV/Gy. Moreover, the shifted band gap exhibited less fading up to 74 days.

Impact of post-deposition annealing on the optical, electrical, and structural properties of CdS thin films for solar cell applications

In this study thermally evaporated cadmium Sulfide (CdS) thin films with the thickness of 100 nm were fabricated at 150 °C under the pressure of 2 × 10−5 mbar and subjected to annealing treatment at various temperatures. The optical, electrical, and structural properties of CdS thin films, which were influenced by annealing treatment, were then studied using ultraviolet–visible (UV–Vis) spectroscopy, Hall effect measurement system, X-ray diffraction (XRD), Raman spectroscopy and Atomic force microscopy (AFM) analysis. The energy band gap was found to decrease from 2.402 eV for the as-grown CdS film to 2.250 eV for the film annealed at 450 °C. The electrical parameters of CdS thin films, such as carrier concentration, resistivity and mobility, were then calculated using the Hall effect measurement system; these were improved with the increase of the annealing temperature up to 350 °C. The crystallite size of the preferred (111) orientation was in the range of 12–40 nm and increased with annealing temperature. The increase in the intensity of peaks and shifting peaks toward the single-crystal mode was observed in the Raman spectra of the annealed CdS thin films. The AFM images also revealed that the film roughness increased with heat treatment. Further, the obtained SEM images showed the uniform surface of the film. The efficiency of the designed solar cell was in the range of 21.84–22.18 %; it was increased by using the annealed CdS films. The present work, thus, introduced the annealed CdS thin film at 350 °C as a promising window layer to fabricate highly efficient CdTe-based solar cells.

High-performance blue light photodetector based on PANI/CdS heterojunction

The pursuit of innovative and enhanced p-n junction photo-diodes for application in optical, optoelectronic, and microelectronic devices has become a global research focus. These diodes' fundamental operation hinges on exploiting disparities in band gaps and electronic structures of constituent materials, thereby enabling the rectification of electrical current, permitting it to flow in a single direction. In this study, we present the design and fabrication of a high-performance blue light photodetector, which uses an n-type cadmium sulfide (CdS) thin film and a p-type polyaniline (PANI). The PANI/CdS heterojunction photodetector demonstrates exceptional performance characteristics, achieving a responsivity of approximately 32 mA/W, a detectivity of approximately 4 × 1010 Jones, and a sensitivity of 5.9 × 104 % under blue light illumination at an applied bias of 30 V. Furthermore, this photodetector exhibits a remarkable rectification ratio of 78 and an impressively short response time of 60 μs. The outstanding performance attributes, including rapid response speed and rectification behavior, are attributed to the surface passivation of the CdS material and PANI chain and CdS linkage mediated states, which effectively reduces the dark current. This process enhances the efficient and rapid transport of photo-generated carriers, whereas, the interfacial nature concurrently reducing photocurrent during reverse bias conditions, thus facilitating the observed rectification effect. This research presents a significant advancement in the area of high-performance photodetectors, holding promise for a multitude of applications across optical, optoelectronic, and microelectronic devices.

Characterization of sol gel derived spin coated copper incorporation of CdS films for nonlinear optical applications

The sol-gel derived spin-coated Copper (Cu) doped cadmium sulphide (CdS) thin films were deposited on glass substrates. The structural, optical, electrical, and non-linear properties of the films have been investigated in detail. The crystal structure of the Cu-doped CdS films was found to be the hexagonal phase, and an improvement in the crystallinity was observed. The optical absorbance was found to change with deposition parameters, and the bandgap of the films was found to be 2.3 eV, which varied with doping and annealing. The photoluminescent properties of the films showed green and near band edge emission. The electrical characteristics of the Cu-doped CdS films were investigated by Hall effect measurements. The copper doped CdS thin films exhibited prominent NLO properties. The NLA coefficients β obtained are of the order of 10−9m/W. The nonlinear refractive index n2 and nonlinear susceptibility χ (3) values were found to be of the order of 10−11 esu.

Enhancing the Photovoltaic Performance of Cd(1−x)ZnxS Thin Films Using Seed Assistance and EDTA Treatment

This research article provides a comprehensive investigation into the optoelectronic characteristics of three distinct types of cadmium sulfide (CdS) thin films, namely: (a) conventionally prepared CdS thin films using chemical bath deposition (CBD-CdS), (b) CdS thin films produced via chemical bath deposition with the inclusion of zinc (CBD-Cd(1−x)ZnxS, x = 0.3), and (c) CdS thin films synthesized using a seed-assisted approach, treated with ethylenediaminetetraacetic acid (EDTA), and incorporating zinc (ED/CBD + EDTA-Cd(1−x)ZnxS). The investigation reveals that the crystallite size of these thin films decreases upon the addition of EDTA to the reaction solution, leading to an increase in the inter-planar spacing and dislocation density. Furthermore, a blue shift in the transmittance edge of the ED/CBD + EDTA-Cd(1−x)ZnxS samples compared to CBD-CdS implies modifications in the band gaps of the deposited films. The incorporation of Zn2+ into the reaction solution results in an increased band gap value of up to 2.42 eV. This suggests that Cd(1−x)ZnxS thin films permit more efficient photon transmission compared to conventional CdS. Among the three types of films studied, ED/CBD + EDTA-Cd(1−x)ZnxS exhibits the highest optical band gap of 2.50 eV. This increase in the optical band gap is attributed to the smaller crystallite size and the splitting of the tail levels from the band structure. Additionally, the increment in the optical band gap leads to reduced light absorption at longer wavelengths, thereby enhancing the electrical properties. Notably, ED/CBD + EDTA-Cd(1−x)ZnxS thin films demonstrate improved photovoltaic performance in a photoelectrochemical (PEC) cell, characterized by enhanced open-circuit voltage (363 mV, VOC), short-circuit current (35.35 μA, ISC), and flat-band voltage (−692 mV, Vfb). These improvements are attributed to the better adhesion of CdS to the fluorine-doped tin oxide (FTO) substrate and improved inter-particle connectivity.

Thermal Annealing Impact on Optical Properties of Spin-coated P3HT: CdS Thin Film

Polymers are flexible materials that can be easily processed and are formed into a thin film by several methods such as spin-coating, dip-coating, film-casting, and printing. The spin coating method has been extensively utilized in fabricating solution-prepared organic/inorganic electronic devices, this technique is positively efficient in generating thin film apart from being a flexible method to execute. In this study, poly(3-hexylthiophene) (P3HT) material is selected as polymer and cadmium sulphide (CdS) as nanoparticles to produce a hybrid nanocomposite thin film through the process spin-coating method. The P3HT and cadmium ion solution were used to fabricate a thin film onto a quartz glass substrate at a spin speed of 500 rpm for 10 seconds. This spin-coated thin film was heated at different temperatures such as 40°C, 80°C, 120°C, and 160°C for optical properties using a UV-Vis spectrophotometer. The UV-Vis absorption spectra of P3HT: CdS indicated absorption peaks in the UV region, which were ascribed to the band gap of the P3HT: CdS thin film. Our results showed that the optical properties of the P3HT: CdS be contingent on the annealing temperature. The film at room temperature yielded a band gap value of 1.98 eV, at 40°C it resulted in 1.99 eV. The band gap value was increased when annealed at 80°C with 2.02 eV. Annealing temperatures were then raised to 120°C and 160°C, leading to band gap values of 3.11 eV and 2.80 eV respectively.

Optical Properties of CuCdS Thin Film Prepared by Vacuum Thermal Evaporation Technique

This study reports on the synthesis and characterizations of copper cadmium sulfide (CuCdS) thin films prepared using the vacuum thermal evaporation technique with copper sulfide and CdS as precursors in a 1:1 molar ratio. The structural properties of the thin films were analyzed using X-ray diffraction (XRD) which revealed that the main composition of the thin film was CdS with the preferred orientation of the (101) plane. The optical properties were examined using UV–Vis spectrophotometry. The photosensitivity of the films was determined using I–V measurements performed with a two-probe technique. The prepared CuCdS thin films have high optical transmittance of 92%.

Photosensitivity reversal in solution-processed Copper Zinc Tin Sulphide/Cadmium Sulphide superstrate junction

Inverse photosensitivity is a sought-after property for the development of photonic devices and non-volatile memories with low power conversion. Herein, we report on the development of a superstrate-type thin film junction exhibiting inverse photosensitivity which does not involve the use of a pricy transparent conducting oxide layer, providing a method for engineering low-cost thin film devices. Sequential ionic layer adsorption reaction (SILAR) was used to grow Copper Zinc Tin Sulphide (CZTS) and Cadmium sulphide (CdS) large area thin film p-n diode junction. Uniform CZTS thin films with an area of ∼10 cm2 which were free of pin holes or voids could be deposited using an optimized SILAR process recipe. The grown CZTS films exhibited an electrical resistivity of 4.4 × 10−4 Ωm using silver (Ag) electrodes. CdS thin films were sub-sequentially grown over the CZTS layer to form a p-n junction. A knee voltage of 0.2 V in the device configuration “glass/CZTS/CdS/Ag” was observed in the current voltage characteristics. The as-prepared and the vacuum-annealed p-n junction exhibited negative photosensitivity of magnitude 0.21 and 0.16 respectively. The air-annealed device structure exhibited photosensitivity of 216.

To Study the Cadmium Sulphide Thin Films Synthesis by Simple Spin Coating Method for Energy Application

The paper examines the properties of CdS thin film, which is used for window material of solar cells and optical devices. The cadmium sulfide (CdS) thin film was prepared by sol-gel method on glass and ITO substrate. Prepared thin film dried in a vacuum oven at 70℃. Thin film and powder of CdS characterized for structural, optical, and electrical properties by X-ray Diffractometer (XRD), UV-Visible spectrometer, and Keithley spectrometer. The average crystallite sizes, microstrain, and dislocation density of the samples were calculated by the Debye Scherrer formula. The optical band gap of CdS calculated by the Tauc-plot method and obtained 2.40 and 2.41eV for powder and film. The absorption wavelength of CdS is suddenly decreased near 280nm and becomes flat in the higher wavelength region. The FTIR spectrometer is used to identification of unknown materials and bond formation. The bond formation, imperfections, and impurities were observed by the PL spectrometer. Keithley spectrometer is used for I-V characteristics and calculates electrical resistivity by Ohms law.