Sulfide Films Research Articles

Iodine- and Oxygen-Free Sensitization Process for VPD-PbS:IO Detectors

Uncooled lead salt detectors have significant advantages in developing the next generation of infrared detectors with SWaP3 features. Herein, a one-step pure nitrogen (N2) sensitized process is proposed to simplify the fabrication process for a wafer-scale lead sulfide (PbS) film fabricated by a modified low-temperature vapor physical deposition (VPD). A room-temperature peak detectivity of 4 × 1010 Jones is achieved after one-step pure N2 sensitization process carried out for VPD-PbS:IO films, which is comparable to the detectors fabricated from the standard chemical bath deposition (CBD) process. The VPD fabrication technology with an iodine-free sensitization process provides an available route for promoting the commercial application of uncooled infrared detectors.

Crystallization of antimony sulfide films on stainless steel substrates obtained by sequential chemical bath deposition

Antimony sulfide (Sb2S3) films have been typically deposited on glass substrates, however, there are a few reports about its deposition on stainless steel substrates. In this work, Sb2S3 was successfully deposited on stainless steel substrates for the first time using sequential chemical bath deposition (CBD) at 2 °C and thermally treated at 300 °C by 5 min in air. XRD and Raman spectroscopy analysis revealed that the as deposited Sb2S3 films exhibits an amorphous phase while the thermally treated has a polycrystalline nature with an orthorhombic structure. An increase in (002) crystalline plane was favored with the increases in deposition layers and was not observed an increase in the oxide phases. The optical band gap was calculated directly on stainless steel substrates by diffuse reflectance and Kubelka-Munk function, and was found a band gap of 2.36, 1.78, 1.71 and 1.75 eV for amorphous, 1 layer, 2 layers, and 3 layers, respectively. The SEM analysis revealed that the sequential deposition improves the surfaces of the Sb2S3 films on stainless steel substrates, and the atomic ratio measured by EDS is near to 1, however the properties of Sb2S3 films were not strongly affected. Our results suggest that the properties of Sb2S3 films on stainless steel substrates can be used for the development of flexible solar cells.

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.

Atomic structure of self-buffered BaZr(S, Se)3 epitaxial thin film interfaces

Understanding and controlling the growth of chalcogenide perovskite thin films through interface design is important for tailoring film properties. Here, the film and interface structure of BaZr(S,Se)3 thin films grown on LaAlO3 by molecular beam epitaxy and postgrowth anion exchange is resolved using aberration-corrected scanning transmission electron microscopy. Epitaxial films are achieved from self-assembly of an interface “buffer” layer, which accommodates the large film/substrate lattice mismatch of nearly 40% for the alloy film studied here. The self-assembled buffer layer, occurring for both the as-grown sulfide and post-selenization alloy films, is shown to have rock-salt-like atomic stacking akin to a Ruddlesden–Popper phase. These results provide insights into oxide-chalcogenide heteroepitaxial film growth, illustrating a process that yields relaxed, crystalline, epitaxial chalcogenide perovskite films that support ongoing studies of optoelectronic and device properties.

A Versatile InF3 Substituted Argyrodite Sulfide Electrolyte Toward Ultrathin Films for All‐Solid‐State Lithium Batteries

AbstractAll‐solid‐state lithium batteries (ASSLBs) incorporating sulfide solid electrolytes capture great attention due to their intrinsic safety features and high energy density. Nevertheless, the implementation of sulfide solid electrolytes faces significant challenges, including moisture sensitivity, narrow intrinsic electrochemical windows, and excessively thick solid electrolyte layers. Here, the substitution of In for P and F for Cl in argyrodite sulfide Li5.7PS4.7Cl1.3 is presented. With appropriate elemental substitutions, the Li symmetric cells exhibit a high critical current density value of 2.5 mA cm−2 and deliver prolonged plating/stripping over 1000 h at 1 mA cm−2 and 25 °C. Further, the Li5.82P0.94In0.06S4.7Cl1.12F0.18 displays high chemical stability toward organic solvents, which is further demonstrated by the density functional theory (DFT) calculations. Using polyisobutylene as a binder, a uniform sulfide film (35 µm) is prepared by slurry casting and hot pressing process, delivering a high ionic conductivity of 1.4 mS cm−1 at 25 °C. Coupled with FeS2 and LiCoO2 cathode, the all‐solid‐state lithium metal cell exhibits a long cycling life and excellent rate performance. This study provides a design strategy and reveals the importance of high‐performance sulfide SEs in the scalable production of sulfide film.

Insights into the flotation performance of ethylenediamine surface modified hemimorphite: Experimental and DFT study

Upon utilizing micro-flotation, contact angle, AFM, ToF-SIMS, XPS, ICP-OES, and DFT calculations, the influence of ethylenediamine (EDA) on the flotation mechanism of hemimorphite was investigated. The addition of EDA to the flotation system led to a 25.15 % increase in flotation recovery efficiency. Contact angle and AFM analysis indicated that EDA enhanced both the hydrophobicity and surface roughness of hemimorphite. Subsequently, ToF-SIMS deep profiling analysis indicated that EDA modification facilitated the incorporation of sulfur ions into the internal structure of hemimorphite, forming a uniform zinc sulfide film. Furthermore, XPS and ICP-OES analysis demonstrates an increase in sulfides on the surface of the hemimorphite after EDA modification. Additionally, the results of DFT calculations showed that the adsorption energy of an EDA molecule on the hemimorphite (1 1 0) surface was −956.492 kJ/mol.

The Impact of Thermal Treatment on the Structural, Optical and Electrochemical Characteristics of Tin Sulfide Films

The development of eco-friendly, cost-effective, and naturally abundant electrode materials for supercapacitors is gaining critical importance in current energy storage research. This study focuses on the synthesis of tin sulfide (SnSx) films via the eco-friendly successive ionic layer adsorption and reaction (SILAR) method, employing varying quantities of L-ascorbic acid (0.8 and 1.0 g) as a reducing agent. Tin sulfide films were deposited on fluorine-doped tin oxide (FTO) glass substrates and subsequently annealed in an inert atmosphere at temperatures ranging from 200 to 400 °C, resulting in thin films of varying thicknesses (100–420 nm). The structural and compositional characteristics of the films were thoroughly analyzed using Raman spectroscopy to confirm the purity and spectroscopic signatures of the sulfides. Further characterization was performed to assess the films’ morphology (scanning electron microscopy, SEM), phase composition (X-ray diffraction, XRD), surface chemical states (X-ray photoelectron spectroscopy, XPS), optical properties (UV–Vis spectroscopy), and electrical properties (Hall measurements). The gathered data were then used to evaluate the potential of tin sulfide films as electrode materials in supercapacitors, highlighting their suitability for sustainable energy storage applications.

Sandwich-structured polymer dielectrics exhibiting significantly improved capacitive performance at high temperatures by roll-to-roll physical vapor deposition

Electrostatic capacitors with ultrahigh power density are the key components in modern electrical and electronic systems. Polymers are preferred dielectrics for high-voltage electrostatic capacitors, however, unable to meet the ever-growing high-temperature requirements in emerging applications, such as electric vehicles, and photovoltaic power generation. In this work, sandwich-structured Polyphenylene sulfide (PPS) films with Al2O3 as the coating layer have been prepared by using roll-to-roll magnetron sputtering. The incorporation of Al2O3 coating layers enhances the potential barrier height at the electrode/dielectric interface, thereby impeding charge injection from electrodes and suppressing high-temperature electrical conduction. Consequently, the sandwich-structured PPS films demonstrate significantly improved breakdown strengths and enhanced capacitive performance at elevated temperatures compared to neat PPS films. The roll-to-roll magnetron sputtering process employed in fabricating these sandwich-structured dielectric films is highly compatible with large-scale capacitor film production. Thus, sandwich-structured PPS films hold promise in addressing the challenge of scalable fabrication of high-performance, high-quality polymer films required for high-temperature capacitive energy storage.

CuxS films as photoelectrodes for visible-light water splitting

Copper sulfides are appealing semiconductors for optoelectronics applications requiring visible-light activity, such as solar water splitting, due to their relatively low band gaps and earth-abundance. This study investigates the effect of deposition conditions, including substrate temperature and background gas pressure, on the characteristics and photoelectrochemical performance of copper sulfide (CuxS) films grown by pulsed laser deposition (PLD) on Si (100) substrates. The results reveal that varying the deposition parameters influences the crystalline phases, morphology, and optoelectronic properties of the films. For deposition at room temperature, the films exhibited covellite CuS phase, while elevated deposition temperatures (250 °C and 500 °C) led to the formation of Cu1.8S and Cu2S phases, resulting in narrowing of the band gap, with the increased temperature also enhancing the film crystallinity and surface roughness. As a result of the changes in film morphology and crystal structure, photocurrent density magnitudes increased with higher deposition temperatures, reaching 0.747 mA/cm2 at −0.8 V for films deposited at 500 °C under vacuum, at least an order of magnitude higher than reported in comparable previous studies of the photoelectrochemical performance of CuxS. Background gas pressure only slightly affected the photocurrent density, with changes in photoactivity also correlating with changes in film roughness and band gap. The results demonstrate the good visible-light activity and behavior of CuxS as a stand-alone photoelectrode material, with tunability based on the fabrication conditions, suggesting their potential use in photoelectrochemical and other solar energy conversion applications.

Structural, morphological, compositional and optical properties of CoS2 thin films synthesized by adsorption-diffusion method

CoS2 thin films on PA 6 sheets were successfully formed by a two-step adsorption-diffusion method. A solution of pentathionate acid and a solution of Co(II) in complex form were used as a source for the formation of cobalt sulfide films. It has been established that increasing the duration of the first stage of the process, as well as increasing the temperature of the Co(II) precursor solution, plays a decisive role on the surface quality and positive physical properties of the resulting CoS2 films. The surface morphology, physical properties and elemental composition of the obtained CoS2 films have been investigated by means of XRD, SEM/EDS, ICP-OES and AFM. The formed CoS2 thin films exhibit a broad absorption edge with a high absorption coefficient (α ≈ 104 cm−1). UV–Vis studies of films have revealed a significant influence of film formation conditions on the values of their optical band gap.

(Invited) Low Temperature Atomic Layer Deposition Processes for Large-Area Synthesis of 2D Transition Metal Dichalcogenides

2D materials have been the focus of intense research in the last decade due to their unique physical properties. This presentation will highlight our recent progress on the large-area synthesis of two-dimensional transition metal chalcogenides for nanoelectronics using advanced atomic layer deposition cycle schemes. First, how we can use advanced cycle schemes to deposit wafer-scale polycrystalline MoS2 thin films at very low temperatures down to 100 °C. We have identified the critical role of hydrogen during the plasma step in controlling the composition and properties of molybdenum sulfide films. By increasing the H2/H2S ratio or adding an extra hydrogen plasma step to our ALD process, we are able to deposit pure polycrystalline MoS2 films at temperatures as low as 100 °C. To the best of our knowledge, this represents the lowest temperature for crystalline MoS2 films prepared by any chemical gas-phase method.[1]The most dominant methods for preparing MoS2 via ALD is to alternately expose a substrate to a metalorganic precursor and a hydrogen sulfide (H2S) or a plasma containing H2S. H2S is a corrosive, toxic, and flammable gas that is heavier than air, which makes it hazardous and expensive to store, install, and transport. Alternative sulfur precursors in the solid or liquid phase would be beneficial in terms of cost and safety and would require the installation of no additional hardware for most ALD reactors. In the second half of this contribution, the widely researched ALD process using bis(tert-butylimido)bis(dimethylamino)molybdenum(IV) ((tBuN)2(NMe2)2Mo) and H2S plasma is compared to a novel ALD process using (tBuN)2(NMe2)2Mo, hydrogen plasma, and di-tert-butyl disulfide (TBDS), which is an inexpensive, liquid-phase sulfur precursor.[1] M. Mattinen et al., Chem. Mater. (2022), 34, 5104

Concentrations Influence of Complexing Agents on the Physicochemical Properties of Chemical Bath Deposited n‐Type FeSxOy for Homostructure Solar Cell

A chemical bath deposition (CBD) is applied to deposit n‐type iron sulfide (FeSxOy) film on fluorine (F)‐doped tin oxide (SnO2)–FTO substrate. The duration, temperature, and magnetic stirrer's speed in CBD are 3 h, 75 °C, and 100 revolutions per minute. The influence of complexing agents’ concentration (≤200 mm)–acid (tartaric and lactic) on the physicochemical properties of film is studied. All films are n‐type semiconductors with large bandgap (2.95–3.58 eV) and contain high oxygen (≈56–83%). Scanning electron microscopy image shows the 50 mm tartaric acid film has a uniform and denser surface morphology. FeSxOy film with tartaric acid has lesser goethite and hematite peaks in X‐ray diffraction than lactic acid. The FeSxOy film with 100 mm lactic acid exhibits a slightly higher transmittance at ≈350–450 nm. The FeSxOy homostructure reveals average open‐circuit voltage (Voc) = 0.45 V, short‐circuit current (Jsc) = 0.0003 mA cm−2, fill factor =38%, and efficiency (η) = 0.57%.

Influence of concentration on optical and structural properties of zinc sulfide films using spray pyrolysis technique

Influence of concentration on optical and structural properties of zinc sulfide films using spray pyrolysis technique

Optoelectronic properties of perovskite thin films derived from lead sulfide via radio frequency magnetron sputtering: effect of the substrate temperature

Methylammonium lead iodide (CH3NH3PbI3; MAPbI3) films were fabricated from sputtered lead sulfide (PbS) films prepared at various substrate temperatures according to the Thornton structural zone model. PbS films were converted to lead iodide (PbI2) and finally to MAPbI3 in a two-step gas-phase reaction. The increase in substrate temperature caused the morphology to change to fibrous interconnected grains, which played an important role in improving the optoelectrical properties of perovskite films. Moreover, enhanced charge transport of MAPbI3 films was observed owing to the fibrous interconnected PbI2 precursor, which was confirmed by a higher absorption coefficient and longer carrier lifetime.

Electric field induced second harmonic generation in arsenic sulfide deposited by thermal evaporation.

Electric field induced second harmonic (EFISH) measurements are performed on thin films of arsenic sulfide deposited on chromium coated fused silica substrates by thermal evaporation of amorphous As2S3 bulk material. EFISH allows to widely tune the second-order optical susceptibility (χ(2)). An observed shift of the minimum of the second harmonic generation (SHG) intensity away from 0 V reveals a non-EFISH bulk χ(2), which is unexpected for amorphous materials. Additional SHG measurements on as-deposited films for investigation of the non-EFISH bulk χ(2) show Maker fringe patterns. Analyzing them and calibrating the SHG response against beta barium borate (BBO) crystal allows us to extract the components of the χ(2) tensor. The main component of this non-EFISH bulk χ(2) has a value of ∼0.22 pm/V. By increasing the χ(2) by applying the dc electric field a maximum value of 3.8 pm/V was achieved in EFISH measurements. This value is comparable to the χ(2) of traditional nonlinear crystals, e.g., BBO, which makes arsenic sulfide an interesting candidate for nonlinear hybrid structures.

Substrate Temperature Effect on the Structural, Optical and Morphological Proprties of Cobalt Sulfide Thin Films Deposited Using Spray Pyrolisis

Abstract Thin films of cobalt sulfide were grown on glass substrates at four different temperatures (250 °C, 300 °C, 350 °C and 400 °C) using spray-pyrolysis technique. The precursor solutions were prepared using cobalt chloride and thiourea. The effect of deposition temperature on the structural, morphological, and optical properties of cobalt sulfide thin films was investigated using different experimental techniques such as X-ray diffraction (XRD), and UV-visible spectrophotometry, Fourier Transform Infrared Spectroscopy (FT-IR) and four-probe method. The XRD analysis showed that crystallite size varies from 9.76 to 14.11 nm with increasing the deposition temperature. UV-visible data analysis shows a decrease in the band gap energies with increasing temperature (1.82 eV for 250 °C, 1.76 eV for 300 °C, 1.72 eV for 350 °C, and 1.65 eV for 400 °C). The analysis of the chemical composition by FTIR confirmed the presence of Co, S elements. On the other hand, the electrical conductivity of the cobalt sulfide thin films increased owing to the increase in the crystallite size and reduction of defects density.

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.

Deposition of Fe-doped CdS films by spray pyrolysis from various precursors

Iron-doped cadmium sulfide films (Fe–CdS) were produced by spray pyrolysis using iron nitrate, chloride and sulfate as iron precursors. Based on experimental analysis data and thermodynamic calculations, it was found that the composition, uniformity and surface morphology of the films significantly depend on the nature of the iron precursor. It has been found that all synthesized Fe–CdS films can be used as master alloys for the manufacture of Fe:ZnSe laser elements.

Fusion Bonding Technique for Solvent-Free Fabrication of All-Solid-State Battery with Ultrathin Sulfide Electrolyte.

For preparing next-generation sulfide all-solid-state batteries (ASSBs), the solvent-free manufacturing process has huge potential for the advantages of economic, thick electrode, and avoidance of organic solvents. However, the dominating solvent-free process is based on the fibrillation of polytetrafluoroethylene, suffering from poor mechanical property and electrochemical instability. Herein, a continuously solvent-free paradigm of fusion bonding technique is developed. A percolation network of thermoplastic polyamide (TPA) binder with low viscosity in viscous state is constructed with Li6PS5Cl (LPSC) by thermocompression (≤5MPa), facilitating the formation of ultrathin LPSC film (≤25µm). This composite sulfide film (CSF) exhibits excellent mechanical properties, ionic conductivity (2.1 mS cm-1), and unique stress-dissipation to promote interface stabilization. Thick LiNi0.83Co0.11Mn0.06O2 cathode can be prepared by this solvent-free method and tightly adhered to CSF by interfacial fusion of TPA for integrated battery. This integrated ASSB shows high-energy-density feasibility (>2.5 mAh cm-2 after 1400 cycles of 9200 h and run for more than 10 000 h), and energy density of 390 Wh kg-1 and 1020 Wh L-1. More specially, high-voltage bipolar cell (≥8.5V) and bulk-type pouch cell (326 Wh kg-1) are facilely assembled with good cycling performance. This work inspires commercialization of ASSBs by a solvent-free method and provides beneficial guiding for stable batteries.

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.