Physics of the Solid State最新文献

A basic photonic device is engineered using two resonators attached either at two distinct points (forming a U-shaped structure) or at the same location (creating a crossed structure) along a waveguide. This configuration is designed to generate Fano and electromagnetically induced transparency (EIT) resonances within the transmission spectrum. These resonances arise due to internal interactions within the structure: Fano resonances occur when the resonance is near a transmission zero, while EIT resonances manifest when positioned between two transmission zeros. As an application, Fano resonances, characterized by their asymmetric profile, allow for the design of highly selective optical filters. These filters are capable of distinguishing between wavelengths that are very close together, which is crucial for telecommunication systems and integrated photonic circuits.

In this study, copper sulfate pentahydrate (CuSO₄·5H₂O) single crystals, measuring up to 8 × 8 × 2 cm, were successfully grown using the hot plate technique. The synthesized crystals were characterized using several analytical methods, including X-ray diffraction (XRD), UV-visible spectroscopy, Brunauer–Emmett–Teller (BET) surface area analysis, and cyclic voltammetry (CV). XRD analysis confirmed that the crystals possess a triclinic structure. Optical property assessments revealed broad transparency in the visible spectrum, with a band gap (E_g) of 4.02 eV as determined by UV-visible spectroscopy. BET analysis showed a surface area of 1.015 cm²/g and a pore volume of 0.0025 cm³/g. Additionally, etching experiments were performed over varying durations to preserve the crystal structure and investigate surface behavior. These findings provide valuable insights into both the growth and properties of CuSO₄·5H₂O crystals, suggesting their potential applications in various scientific fields.

Elastic constants с_ij of thiogalates CdGa₂S₄, CdGa₂Se₄, CdGa₂Te₄, and ZnGa₂Sе₄ are calculated using the density functional theory (DFT). The elastic moduli B have been calculated. The regularities have been found in the dependences of the optical phonon frequencies on the atomic masses in ({{{text{A}}}^{{{text{II}}}}}{text{B}}_{2}^{{{text{III}}}}{text{C}}_{4}^{{{text{VI}}}}) compounds. The force constants of interatomic bonds in CdGa₂Te₄ and ZnGa₂Sе₄ compounds are determined.

Ethylenediamine-doped (EDA-doped) polyaniline (PANI) films were deposited via spin coating technique on a glass substrate. The samples were annealed at different times and temperatures. The characterizations of the prepared PANI films were described by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). It is found that the conductivity changes under deep mouth exhaling for 150/1 h sample is 1.65 times faster than the films annealed at 100°C/4 h. The response and recovery time of the 150/1 h EDA-doped PANI film is decreased by order of 0.63 and 1.29 s than those films dried at 100°C for 4 h, respectively. The 150/1 h EDA doped PANI film during deep exhaling its conductivity increased abruptly from 2.2 × 10^–7 to 0.026 S/cm^–1. In a few seconds, following an inhalation, there occurs a complete transition to the dry state conductivity. Furthermore, the increment in conductivity of the EDA-doped PANI films was determined at various RH levels (20, 40, 60, 80, and 90%) with exposure and evacuation of the humid air. The doped PANI sample annealed at 150°C for 1 h exhibit the highest conductivity at 90% RH. The conductivity was increased from 2.16 × 10^–7 S/cm for the insulating state at the dry state to 0.23 S/cm for the semiconducting state at 90% RH. Consequently, the 150/1 h sample showed an increase in conductivity by order of 10⁶ at 90% RH. For all samples, the conductivity progressively rises as the RH value increases till 90% of RH value samples exhibit an abrupt increase in conductivity except the 100°C/4 h sample. The highest conductivity is 0.041 S/cm at 90% RH obtained for the case of 150/30 min sample, whereas the 150/1 min and 100/4 h films show maximum conductivity of 0.027 and 0.007, respectively.

A modified Bridgman technique was used to crystallize the Tl₄In₃GaS₈ compound. The rate of change in the thermoelectric power (TEP) as a function of temperature of the Tl₄In₃GaS₈ compound is measured within the temperature range (218–402 K). Measurements revealed that the conductivity of the crystals was n-type. Investigations were conducted into the connection between TEP, charge carrier concentration, and electrical conductivity. The experimental results were used to calculate a number of physical properties, including as mobilities, diffusion coefficients, diffusion lengths, effective masses, and carrier relaxation periods. The overall behavior of the semiconductor is shown by these features. According to our findings, asgrown Tl₄In₃GaS₈ crystals are typically n-type and have the potential to be employed as thermoelectric power generating possibilities.

This paper successfully synthesized Bismuth oxide (Bi₂O₃) nanoparticles (NPs) using the sol–gel method as Bismuth nitrate pentahydrate as a precursor. The average crystallite size of the NPs was characterized by X-ray diffraction (XRD) analysis and the size of the NPs found to be 17 nm. For the band gap measurement UV-visible spectra of NPs were recorded and it was found to be 2.7 eV. The surface morphology of Bi₂O₃ NPs was examined through field emission scanning electron microscopy (FESEM) showing spherical nature-like morphology. The gas sensor was fabricated using as-prepared Bi₂O₃ NPs by standard screen-printing technique and it was tested for various gases such as NH₃, NO₂, ethanol, LPG, and methanol as a function of operating temperature. The effect of operating temperature and gas concentration were investigated in detail to understand Bi₂O₃ NPs sensor for NH₃ gas and found to be very efficient.

In this paper, we explore the magnetic, optical, and antibacterial properties of ({text{CoF}}{{{text{e}}}_{2}}{{{text{O}}}_{4}}) (CFO), ({text{C}}{{{text{o}}}_{{0.98}}}{text{A}}{{{text{g}}}_{{0.02}}}{text{F}}{{{text{e}}}_{2}}{{{text{O}}}_{4}}) (CAFO), and ({text{C}}{{{text{o}}}_{{0.98}}}{text{T}}{{{text{i}}}_{{0.02}}}{text{F}}{{{text{e}}}_{2}}{{{text{O}}}_{4}}) (CTFO) and spinel ferrite nanocrystals. The XRD analysis of these crystals reveals a single-phase cubic structure of (Fdbar {3}m) space group with a crystallite size of 45, 46, and 41 nm, respectively. The room temperature magnetic measurement shows that CTFO has the highest saturation and remanent magnetization, whereas CFO has the highest coercivity and magnetic squareness ratio. Optical properties of these samples have been taken in the range of 300–900 nm. The band gap is calculated using Tauc’s plot, and it decreases with the doping of ({text{A}}{{{text{g}}}^{ + }}) and ({text{T}}{{{text{i}}}^{{4 + }}}) ions. Antibacterial studies of these samples have been done by disc diffusion method for Gram-positive and Gram-negative bacteria, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), respectively. The compositions have shown better antibacterial response for S. aureus over E. coli. The 200 mg/mL CTFO sample has shown the most effective result against S. aureus bacteria, with 18 mm diameter value of zone of inhibition.

GaS Nanoparticles prepared by laser ablation in a liquid. The nanoparticle structure is studied by XRD, SEM, and EDAX methods. The energy gap width and the character of optical transitions are determined using the optical absorption and photoluminescence spectra.

In this study, we delve into the potential of the halide perovskite material Ca₃SbBr₃ for solar cell applications, using QuantumATK simulation tool. By employing DFT with both GGA-PBE and HSE06 functionals, we thoroughly explored its structural, mechanical, electronic and optical properties. Our study reveals that Ca₃SbBr₃ adopts a cubic crystal structure. The lattice constant for this structure is measured to be 6.336 Å. Notably, the material exhibits a direct band gap of 1.782 eV with GGA and 2.592 eV with HSE06, underscoring its efficiency in solar energy conversion. Moreover, Ca₃SbBr₃ shows strong light absorption, with significant peaks at 629, 396 cm^–1 (3.52 eV) and 245, 951 cm^–1 (3.76 eV), and refractive indices of 2.10 (GGA) and 1.825 (HSE06). These results suggest that Ca₃SbBr₃ holds great promise as a next-generation solar material, thanks to its advantageous electronic and optical properties.

Nanostructured tungsten oxide (WO₃) thin-film sensor materials were deposited on a glass substrate by spray pyrolysis technique (SPT) and investigated their gas sensor properties. As prepared WO₃ thin films were characterized by different techniques such as UV-Visible Spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The optical band gap of film was determined using the absorption spectra obtained with UV-visible spectroscopy which was found to be 2.9 eV. XRD results of the as prepared WO₃ exhibits crystalline structure and favored alignment along the (002) axis. The spray pyrolysis technique used for the preparation of the WO₃ thin film often results in a porous and rough surface with a network of interconnected fiber-like structures., which are ideal for gas sensor applications due to increased surface exposure. The gas sensing performance of the WO₃ thin film was tested towards various gases such as H₂S, NH₃, LPG, H₂, ethanol, CO₂, Cl₂ at different operating temperatures. The WO₃ thin films exhibited their highest gas response to H₂S gas at an operating temperature of 50°C, with fast response and recovery times of 18 and 31 s, respectively. These results suggest that WO₃ thin films could serve as effective H₂S gas sensors.